The Northeast Weather Blog...

Dry weather week for the Middle Atlantic...

By: Blizzard92, 12:11 AM GMT on May 18, 2009

"Afternoon Thoughts" (Updated 5/17)
So after a hectic Sunday morning, I decided to head off to the flower nursery locally in town to get my warm weather vegetables. As I parked I noticed the extremely crowdedness of the local establishment. Heading off to the vegetables, angry children and parent's with lists headed off in a rat race off to the vegetables and tomatoes ramming their cart in front of mine. In fact one woman just about grabbed a cherry tomato plant out of my hand as it was the last one. Unfortunately, the nursery was out of the other plants I needed. I headed off to the local outdoor store and of course they were loaded with vegetables and once again with another busy crowd. Searching for the correct variety, I noted the extreme price for a very small cucumber, etc plant. It was $3.69. I asked a nearby clerk if that was the correct price as before I had seen them at $0.99. She replied and said unfortunately that was the correct price; she began to add that the price skyrocketed not because of the high demand and poor economy but because the plants were packeged in a bio-degradable pot along with recycled paper for the wrapper. I thought to myself about this "Go Green" memo; it appears like much of this is just another retail phenomenon similar to like a Christmas year round. It almost seems like another excuse to get consumers to buy so the the greedy dollar eyed businessman can get a larger profit and more wholesail. While I am all for saving the environment; and yes I do my part, this is all just a media and consumer based motive to get a larger profit. In my opinion let the scientists handle climate change and let the engineers develop more efficient energry development. Whether or not climate change is occuring, which is has not been proven caused by human influence, it seems like once again business is ripping us off just as local gas prices rise only due to the approaching Summer months. While business is business, the unstreetwise consumer needs to make more knowledgeable choices. But after all this little rant; suffice to say I ended up buying the plants, hahaha.

"Regional Radar"

(Courtesy of NOAA)

"Regional Satellite"

(Courtesy of Penn State Meteo.)

"Regional Advisories"

(Courtesy of NOAA)

"Forecast Discussion" (Updated 5/17)
Monday- High pressure will be over the region under a light northwest flow. Radiational cooling from the previous night will allow heavy frost to form in the morning across much of the state excluding major metropolitan areas. Also some dense deep river valley fog may form across central Pennsylvania in the ridge and valley region thanks to the stark air/water temperature contrast (.25mile visibility). The fog will be isolated at best though. After some morning sunshine the temperatures will warm and the fog will burn off for another below normal temperature day. Highs will generally be in the mid 50s across the far north to mid 60s across the warmer southern locales. By Monday evening skies will be completely clear and winds will calm for another extreme radiational cooling night where there could be a 30degree temperature difference between the high and low. Frost formation is likely for the same areas the night before. In fact lows could be a nudge cooler; the old rule of thumb is the second night after a cold front is the coldest. Lows will be in the 30s for most areas with some areas in the mountain valleys in the 20s.

Tuesday- Once again the typical frost and valley fog in the morning will be prevalent for many areas as high pressure remains in control. Cloud cover will be clear expect for a few high topped cirrus clouds, but generally sunshine will prevail. Highs will be nudging back to near normal values around 70 across the southeast to 65degrees across the north. Tuesday night will feature a few more cirrus clouds than the previous nights preventing the extreme radiational cooling like the last two nights before. Lows still though will be below normal to the mid 30s across the north to mid 40s across the south.

Wednesday- A weak backdoor cold front will try to nudge into northern Pennsylvania, but it will encounter a very dry atmosphere and the front will have little to no lift. Still a few rain showers are possible under partly cloudy skies north of I-80. South of I-80 will be under the control of high pressure keeping generally clear skies with a few light cirrus clouds. Rainfall amounts across the north will be very light less than a tenth of an inch. Highs will be near normal with mid 70s for southern Pennsylvania and upper 60s for the north. Once again dewpoints will be relatively low and a fire threat may be prevalent in a few drier valleys. Under partly cloudy skies, Wednesday night will be the warmest night of the week so far with lows in the northern mountains around the upper 40s and lows in the south in the mid 50s to possibly near 57 for near Philadelphia.

Thursday- As high pressure departs the flow turns a bit more southerly allowing warmer and more moist air to funnel into the Middle Atlantic. Dewpoints will rise into the upper 50s to near 60s in the Lower Susquehanna Valley and temperatures will rise to near 80 in the south to near 75 in the north. A light cirrus deck will be around the region with a few afternoon spotty cumulus clouds especially over the Laurel Highlands. Thursday night will be a bit mild with lows slightly above normal in the upper 50s for the south to low 50s across the north.

Friday- The flow gets even a bit more moisture especially aloft allowing for the best chance of precipitation for the week. Sunshine will prevail in the morning with a bit of ground fog in the river valleys which will quickly burn off. Dewpoints in the upper 50s to low 60s combined with the strong May sunshine will cause some after pulse showers and thunderstorms especially over the Laurel Highlands which are aided by orographic lift. Rainfall will be isolated by high in thunderstorms in which some could cause a bit of flash flooding. After the diurnal heating of the day showers and thunderstorms will dissipate for the night for a muggy late May evening. Lows will be in the mid 50s statewide with mostly clear skies.

"Current Surface Map and Weekly History of Jet Stream Position"

(Courtesy of Weather Underground)

"Weekly Forecast" (Updated 5/17)
Pretty calm weather week is in store for the next seven days as high pressure generally remains in control. An abnormal trough will be stationed over the east coast for the first half of the week thanks to that strong cold front passage Saturday and Saturday night. H85s drop below 0C statewide for part of Sunday night through Monday. A 1028mb high pressure will move in overnight Sunday and calm the tight pressure gradient giving way to lighter winds for the rest of the week. H85s will be on the rise by Wednesday rising to (+8)-(+9)C. Dewpoints will also slowly begin to rise as RH values rise back to near 50% or so. Towards the later part of Wednesday a backdoor cold front tries to work into the northern parts of Pennsylvania and may cause a few light rain showers. Generally QPF will be below .1inch. A stalled front and disturbance over the southeast will churn over Florida causing a return to a southwest and moist flow over the Middle Atlantic and will rise dewpoints back in the 50s and 60s by Friday. High pressure will be slowly pushing out to sea, 1024mb. Towards later Friday and Saturday abundant moisture across the Southeast should stream into the region possibly causing some pulse thunderstorms in the late afternoon fueled by diurnal heating. PWATs rise to near 1.5inches, so heavy rain may fall in localized areas with the very intermittent and isolated storms particularily over the mountains in the Laurel Highlands. High pressure noses down from the Canadian Maritimes, 1028mb, and will keep a cold front to our west relatively kept in place until early next week as it poses a threat to our area with showers and thunderstorms towards Monday and Tuesday with possibly a few stronger thunderstorms of should I say the next best threat of severe weather for the Middle Atlantic states.

"Wildfire Outlook" (Updated 5/17)
The wildfire threat is once again a bit elevated in comparison to normal despite the recent heavy rainfall. Gusty northwest winds on Sunday will cause a rapid drying of the topsoil which will further aid fire development later in the week. Dewpoints will be dropping well below the 40% RH spread towards Monday and Tuesday. Winds though will be calming down and temperatures will be cool. But with a somewhat dry top layer of forest floor, it does appear possible that if a accidental fire occurs, it would spread. Natural fires do not seem to be a threat this week. The next best chance of rainfall statewide is not until the weekend and even then the threat looks small. There may be a few backdoor cold fronts this week that may cause a few showers and thunderstorms for northern Pennsylvania with one instance will be Wednesday for the north central mountains. Again QPF will be light and only up to a tenth of an inch. Another instance will be Friday with a bit better chance of rainfall with scattered strong thunderstorms. Rainfall totals may be up to a .5inches in areas that see thunderstorms. Otherwise rainfall this week will be scarce. The only source of moisture for southern areas will be a few morning dews and such.

Here again are the fire criteria for development in Pennsylvania... Link.

Criteria for rapid initiation and spread of wildfires in PA:

1. Winds must be sustained at 15 mph (13 knots) for two hours or more, and

2. Minimum Relative Humidities (which usually occur in the afternoon) must be 30 percent or less, and

3. 10-hour Fuel Moistures must be 15 percent or less (and expected to remain there for two or more days).

"Fire Outlooks from Storm Prediction Center Days 1, 2, and 3"

(Courtesy of NOAA)

"Gardening Outlook" (Updated 5/17)
Ah, it has been a very busy gardening week and weekend. So I got a bit antsy and built another 6x2 raised bed box. I then filled it with 12 bags of soil, 10 bags of garden soil and 2 bags of a hummus/manure mixture. I also added some of the rich soil from here in this fertile valley off the foothill of Blue Mountain in my backyad. It appears to be once again very rich soil much like the other two boxes. I ended up buying and planting my warm weather crops which included three tomato varieties Early Girl, Roma, and Cherry. I also added two pickling Cucumber plants and two zucchini plants. Further more I added to my herb pot a oregano plant and a basil plant next to my tomatoes. I also added a single watermelon plant sort of for an experiment to see how well it does. I also picked up a bunch of my yellow wax bean seeds, but I haven't planted them yet. My cool weather crops are doing fantastic; I just noticed I have a single head of broccoli along with three heads of cauliflower so far. Once they get a bit larger I will prepare them for blanching. Also this year I picked up some mesh netting to protect my blueberry bushes which were picked clean by the birds last year to my sad discontentment. My radishes have been picked throughout this week and are absolutely wonderful and this year a brilliant red color. My lettuce plants are doing wonderful and are harvested nearly every other day (remember I planted 28 plants, hehe). The spinach plants are slow to grow but are making better strives than last year. I also have been continuously been picking a few scallions while thinning out the onion bed so the remaining yellow and red onions can grow to their full extent with the garlic in preparation for picking in the late Summer or early Fall. My herbs are doing fine although something must have nibbled a bit out of my parsley. The leeks seem to still be growing; I do not know much about them so if anyone could offer some advice I would appreciate it. The Swiss Chard tastes wonderful and I will admit I have not had any before this year, hehehe. I am not to sure about the celery plants, they seem to be growing and healthy, but where are the stalks? Snow peas are doing out of this world amazing, remember I planted them back in March. They just seem to have continuous shoots, no flowers yet though.

Elsewhere my other gardens are doing wonderful. I added a large shade garden under a mature flowering plum tree last year so I have been on the search for shade perennials which is quite difficult but I have done alright with some trial and error; I also added a few impatients to add some color. I am hoping to do all my potting which is quite a task, next weekend. As for this week in gardening, temperatures will be below normal to start the week rising to near and slightly above normal by the weeks end. Rainfall will be hard to come by in the next seven days especially for southern Pennsylvania. Rain totals south of I-80 will be less than .25inches for the next seven days and north of I-80 up to .4inches of rain. Frost is a major threat early in the week; perfect radiational cooling conditions and abnormally low dewpoints will carve way for well below normal lows with hard freezes in the north and west and frosts elsewhere. Protect your plants both Sunday and Monday nights especially. I have covered my sensitive vegetables already tonight.

"Soil Moisture Anomalies and 5-day Precipitation Amounts from Hydro Prediction Center"

(Courtesy of NOAA)

"Severe Weather Outlook" (Updated 5/17)
So the recent severe weather wasn't too widespread for Pennsylvania thanks to the underlining marine layer, which kept everything under control similar to a CAP or CIN. But one supercell did occur in extreme northern Pennsylvania over Tioga County where some wind damage did occur. As the mesocyclone moved northward into New York State a tornado occured with some structural damage reported. Also further south in Pennsylvania a late blooming echo of storms formed with the severe core about 3miles north of my house where radar confirmed some very strong rotation to the point of I would have issued a tornado warning thanks to the radar reflectivity which confirmed a small couplet. Wind damage was reported in Dauphin, PA and up in Schuykill County near Pine Grove. I also would not be surprised if a weak EF0 tornado touched down in the mountains near Peters Mountain, the land there is quite rural and slimly populated so it may go undetected. Intense lightning did occur with many of the cells along with extreme rainfall as rain rates at my location nudged 8inches per hour recorded. Flash flooding did occur in a few areas; which was all courtesy of the abnormal PWATs aloft near 2inches. Looking ahead severe weather chances don't look great for the next seven days with the lack of any focal point. Towards next week a strong cold front looks likely to sweep across the nation with potentially some severe weather. The time frame for Pennsylvania would be the Monday-Tuesday frame. Overall though this season does seem a bit more active than last year in which only one report of severe weather occured in all of May. This year; remember the tornado back in March in Lancaster County. As always I will provide a special severe weather blog if something does pop up, for now enjoy the quietness nearly nationwide.

"Severe Weather Outlooks from Storm Prediction Center Days 1, 2, and 3"

(Courtesy of NOAA)

"Monthly Outlook" (May)
Well my April forecast verification looks just ok. My temperature forecast was spot on with near normal to above normal temperatures. Cooler conditions persisted early in the month, but by mid to late month an anomalous near heat wave definition for some areas hit rising the average monthly temperature for all climate reporting stations in the Keystone State. Temperatures averaged near 0-(+1.5) degrees for the month. Now my precipitation called for drier conditions, which did not pan out. Most areas ended up with about .5inches above normal in the rainfall department. Temperature forecasts always are much more uniformed than the at times unpredictable precipitation forecast. May looks to be a transition month for precipitation as the first half looks wet followed by a return of the average summer jet stream that looks to be this summer with trough in west, ridge in central US, southeast ridge, and weak trough in extreme Northern New England. My temperature call is for near normal to slightly above normal temperatures along with near normal precipitation for the month. The best chance of rainfall will be the first half of the month; also the warmest temperatures look to be towards the end of the month. Already the latest guidance is showing the summer jet stream pattern with MCS traveling through the Great Lakes and across just north of Pennsylvania. Latest EURO weeklies also support this. Here are the detailed predictions...

Temperature- Temperatures will be put on a cap for the first half of the month as cloud cover from rainfall will hold temperatures near normal. Soil moisture levels will be +1 deviation above normal. When soil moisture is below normal this allows boundary layer temperatures to be much warmer. Wet soil conditions tend to keep a hold on extreme hot temperatures. Later in the month the Bermuda high looks to nose in with a southerly flow drawing up very warm conditions with highs likely in the 90s several days this month.

Precipitation- Precipitation will be common for the first half of the month under a progressive flow. Precipitation may in fact average above normal the first half of the month. As the pattern transitions drier conditions will occur with only occasional thunderstorms outbreaks providing needed rainfall. The end of the stratiform rainfall will likely occur mid month. By the months end an above normal first half and below normal second half will lead to near normal precipitation. Although as we all know a two week period of dry weather does not at all show that we may have just had a wet four previous weeks.

"Temperature and Precipitation Outlooks from Climate Prediction Center for next 30 days"

(Courtesy of NOAA)

"Tropical Update" (Updated 5/17)
Looking at the latest North America water loop there is an evident area of disturbed weather in the Caribbean. An area of heavy thunderstorms and showers is across Jamaica and parts of eastern Cuba. Latest global models portray this area to move northwest towards Florida and come in contact with a cold front. This will allow for a stationary boundary to form with a disturbance interaction. Heavy rainfall with engulf most of the entire state of Florida as PWATs rise above 2inches which is several devations above normal. Showers and thunderstorms will produce rainfall in excess of 5inches in some locations which may pose some flash flooding issues. This rainfall will be very beneficial as most of Florida has been drought stricken for quite a while. This storm will not likely further development as upper level trade winds are not favorable for development and contain high shear values. This disturbance will try to work its way up part of the east coast with humid tropical air and summer like pop-up showers and thunderstorms for the Southern Middle Atlantic. It remains to be seen how far north the moisture will make it for any possible interactions with Pennsylvania towards the weekend. Further out the GFS continues to develop fantasy tropical systems none of which come to fruitation anyways. It is not uncommon though to get tropical systems in May especially subtropical storms. So in any case those with coastal interests for the next seven days look to breath another side of relief until hurricane season starts which is June 1.

"Latest Tropical Systems including Sea Surface Temperatures"

(Courtesy of Wunderground)

"Here north of Harrisburg 2009 statistics"
(Severe Weather Stats...)
Severe Thunderstorm Watches- 2
Severe Thunderstorm Warnings- 1
Tornado Watches- 0
Tornado Warnings- 0
Total Thunderstorms- 7

(Precipitation Stats...)
Flood Watches- 1
Flood Warnings- 0
Monthly Precipitation- 6.54inches
Yearly Precipitation- 13.40inches

(Temperature Stats...)
Heat Advisories- 0
Excessive Heat Warnings- 0
90degree Days- 2
Highest Temperature- 92degrees

Weekly Forecast

Updated: 1:05 AM GMT on December 28, 2011

Permalink

Middle Atlantic Severe Weather...

By: Blizzard92, 1:24 AM GMT on May 16, 2009

"Thoughts on Severe Weather Outbreak of May 15"
Well there is the potential for the first widespread severe weather outbreak of the season in Pennsylvania. Energy is coming together for the best ingredients right over the central Pennsylvania region over the Middle and Lower Susquehanna Valleys. I have never been a fan of early season severe weather outbreaks as they are quite difficult to forecast. In most all May severe weather forecasts there are never quite all the ingredients together and usually the lacking factor in minimal surface instability. This time of year the jet stream is transforming from winter time stratiform events to pure cold front convective events of the summer. During this time period ahead of cold fronts there are many dirty warm fronts that cause debris clouds and inhibit instability. But with extremely strong sunshine this time of year, in cases sensitive like the current one sometimes the clouds will become overcome. If any factor is lacking and busts this event, it will be the lack of sunshine. Looking back on the semi-quiet severe weather season of 2008 there was only one severe weather report in the whole month of May. It occured in Jonestown in Lebanon County with a high wind report with a small bow echo that moved through Lebanon and Dauphin Counties. But typically we get many of these questionable severe weather outbreaks this time of year. MCS activity will be ongoing overnight also and may cause debris clouds over the Middle Atlantic in the morning too. So for this event the potential is there for a supercellular event with a few embedded squall lines capable of damaging winds and a few isolated tornadoes. If clouds end up preventing any instability, the event will cease to exist other than regular thunderstorms. Also there is such high shear values in the lower level of the trophosphere that a few thunderstorms may even be torn apart.

"Current Weather Setup"
Friday night will feature some pretty close temperature/dewpoint contrasts with nearly 95% RH values by 6am Saturday morning. With a slight southeasterly wind and high dewpoints a fog bank has formed over the Atlantic as evident by evening visible satellite. This will track inland across eastern Pennsylvania likely as some low 400ft ceiling stratus clouds. It remains in question how far inland this makes it. Meanwhile a warm front over Virginia will try to lift north bringing a so called dirty warm sector by morning. Once in the warm sector there will be mostly cloudy skies along with periods of light rain showers. Meanwhile to the west an overnight MCS complex currently over Illinois will being move into a more stable environment by morning causing the remnaints to cause clouds out ahead of the remaining showers. But we have hit mid May and the sun is nearly a month from its peak ray value. The sun should be strong enough to devour some of the cloud cover for a partly to mostly cloudy sky cover in the afternoon. As the front approaches an anomalous low level jet will strengthen over Pennsylvania causing impressive kinematics with 0-6km shear values over 45knots. As pockets of instability develop with 500-1000 j/kg CAPE it appears that isolated thunderstorms will begin to form first along natural boundaries such as a sea breeze type boundary over eastern Pennsylvania where a temperature varient of 15degrees will occur and there will be a difference between sun and fog. Those storms though will be weak. Moisture advection with PWATs near 1.75inches will occur over the Susquehanna Valley combining with some sun shine will cause the best ingredients for severe weather as the front nears. By later in the afternoon low level wind veering should allow for supercellular activity to form. These cells ahead of the front will be the ones capable of tornadoes. They are most likely in the Harrisburg-York-Lancaster-Reading Corridor. EHI values will rise to near 2 and helicity is near the highest on the charts. Undirectional shear aloft should help create the natural spin on the atmosphere. Thermodynamics will be lacking though with only LI values near 0 and max CAPE near 1200 j/kg. The SWEAT index is proving impressive though near 250. As the front approaches western Pennsylvania a squall line will develop with a primary threat of wind damage. Freezing levels are high aloft near 1200ft, so the threat of hail will not be widespread. As the front approaches the marine airmass over extreme southeastern Pennsylvania the storms should weaken. QPF totals will likely be near .5inches for many areas with up to 1inch for areas that received the heaviest storms.

"Current Advisories"


"Current Satellite"

(Courtesy of Penn State Meteorology.)

"Current Surface Map and Weekly History of Jet Stream Position"


"Radar for Western Pennsylvania"

"Radar for Central Pennsylvania"

"Radar for Eastern Pennsylvania"


"Forecasts from Storm Prediction Center"
SPC AC 161256

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0756 AM CDT SAT MAY 16 2009

VALID 161300Z - 171200Z


...UPR OH VLY/NY INTO NRN MID ATLANTIC...
LOW LVL MOISTURE WILL CONTINUE TO STREAM NNE INTO PA/NY AHEAD OF
AFOREMENTIONED COLD FRONT AND W OF DIFFUSE WARM FRONT NOW EXTENDING
CNTRL NJ TO CNTRL NY...SUPPORTING MODEST DESTABILIZATION.
INSTABILITY WILL...HOWEVER...REMAIN MARGINAL DUE TO WEAK MID-LVL
LAPSE RATES AND PRESENCE OF VARIABLE CLOUD COVER. AFTN SBCAPE
SHOULD RANGE FROM 500 TO 1000 J/KG IN NY TO NEAR 2000 J/KG IN MD/NRN
VA.

MODERATE WSWLY MID LVL FLOW WILL EXIST OVER THE NERN STATES TODAY
AHEAD OF APPROACHING TROUGH...WITH 500 MB SPEEDS AOA 40 KTS FROM
CNTRL PA NWD INTO NY. PROFILES SHOULD BE FAIRLY
UNIDIRECTIONAL...ALTHOUGH SOME DEGREE OF LOW LVL VEERING WILL EXIST
INVOF WARM FRONT AND PRE-FRONTAL TROUGH OVER ERN PORTIONS OF PA/NY.
TSTMS SHOULD FORM WITH SFC HEATING ALONG AND AHEAD OF COLD FRONT BY
EARLY AFTN. RESIDUAL PRE-FRONTAL STORMS NOW OVER WV MAY STRENGTHEN
BY LATER THIS MORNING...AND OTHER STORMS MAY FORM BY MID AFTN ALONG
LEE TROUGH ACROSS MD/SE PA.

THE PRIMARY THREAT SHOULD BE BOWING SEGMENTS/SMALL LEWPS WITH STRONG
TO DMGG WIND GUSTS. A COUPLE TORNADOES CANNOT BE RULED OUT GIVEN
STRENGTH OF DEEP SHEAR WITH NWD EXTENT...AND GREATER
MOISTURE/LOW-LVL VEERING FARTHER S AND E. OVERALL SEVERE POTENTIAL
SHOULD REMAIN SOMEWHAT LIMITED GIVEN MARGINAL THERMODYNAMIC
ENVIRONMENT...AND SHOULD DIMINISH TOWARD EVENING.

"Tornado Risks"

"Hail Risks"

"Wind Risks"


"Model Analysis"
It has been while since I scrutinized over the models and each variable. But it is beginning to be that time of year. Winter is the most common season for my indepth model analysis, in fact I inspect each run. But in Summer other than severe weather outbreaks I typically just look at the basic 850 heights, 500mb, and 6 hr QPF charts all for the main global models of the GFS and EURO. Anyways as usual there are model discrepancies with the NAM predicting CAPE values much lower than the GFS more in the 500 j/kg range while the GFS is more up to a max of 1400 j/kg. The SREF and MOS guidance though tends to side with the GFS and there are near 1200 j/kg. This indicates that they try to show more sun than the NAM. In any case below are few of my selected maps that detail important indices for thunderstorm development, heavy rainfall potential, and kinematics aloft. Also keep in mind convective temperatures are in the mid 70s to near 80 tomorrow, so they should be reached for cumulus development. I will update these maps throughout the day. Stay tuned!

"15z SREF Model Forecast Lifted Index Values"

(Saturday evening)

"0z NAM Model Forecast SWEAT, Helicity, and CAPE indices"

(Saturday evening)

"0z GFS Model Forecast Precipitable Waters"

(Saturday evening)

"0z GFS Model Forecast EHI Values"

(Saturday evening)

"My Forecast for Severe Weather"
I like the axis for best severe weather to be in central Pennsylvania and up through the Middle and Lower Susquehanna Valleys. These locations will have the highest threat for an isolated tornado. Wind damage though will be common from western Pennsylvania on eastward as the best dynamics are over the state of Pennsylvania. The highest threat for flash flooding will be over eastern Pennsylvania that has recently been rain socked with 2inches just yesterday and flash flood guidance is near 1.5inches in 6hours for flooding to occur. Cold air aloft is lacking for this event with H85s well near 15C, but some intense lightning may still occur especially in the more cellular cells. Impressive high temperatures also may occur depending on much sun there is and I could see highs near Lancaster if the sun comes out potentially up to 87degrees. Dewpoints will be very high also in the 60s for just about the entire state.

"My Severe Weather Risk Map"

(Saturday)
*Note... It has been a while since my severe weather maps have been posted. For review my probability areas are slightly different than the Storm Prediction Center due to the fact of the somewhat rarity of severe weather in Pennsylvania in comparison to other parts of the country. Therefore my moderate risk for Pennsylvania would be similar to a high end SPC slight risk. My 25-50% chance of thunderstorms include 0% chance of severe weather. My 75% chance of thunderstorms include 5% severe weather. My slight risk of severe weather includes 15% severe weather. My moderate risk includes 30% severe weather and my high risk includes 45% chance of severe weather. And after the storm I will plot the storm reports and forecast warnings over my forecast regions for a verification map.

"Conclusions on Severe Weather Outbreak"
So it is another wait and see event in this ever difficult area for forecasting, Pennsylvania. While nothing is never set in stone for the weather, forecasting here in the Appalachians is much more difficult than other parts of the nation. Geographic features play such a large role and then to our east is the Atlantic Ocean. So cloud cover as usual is in the biggest question of concern and I could see how this event easily fizzles out especially if the warm front does not come far enough north and the cloud cover is thicker than expected. Still though thunderstorms should be around the region despite other factors. The low level jet is quite impressive and if we had impressive thermodynamics such as 2000 j/kg CAPE like in late June, this could have been a pretty impressive tornado outbreak. Depending on how the weekend flows, my next weekly forecast blog may be out Sunday evening. Have a wonderful weekend!!! Feel free to add forecast discussions here and storm reports!

Verification Map...


"Storm Reports"


"Here north of Harrisburg 2009 statistics"
(Severe Weather Stats...)
Severe Thunderstorm Watches- 2
Severe Thunderstorm Warnings- 1
Tornado Watches- 0
Tornado Warnings- 0
Total Thunderstorms- 4

(Precipitation Stats...)
Flood Watches- 1
Flood Warnings- 0
Monthly Precipitation- 4.30inches
Yearly Precipitation- 11.16inches

(Temperature Stats...)
Heat Advisories- 0
Excessive Heat Warnings- 0
90degree Days- 1
Highest Temperature- 92degrees

Severe Weather Outbreak Blog

Updated: 1:49 PM GMT on May 17, 2009

Permalink

May is for gardening...

By: Blizzard92, 8:32 PM GMT on May 10, 2009

"Afternoon Thoughts" (Updated 5/10)
Good Sunday afternoon!!! I know that many of us on are gardeners. Do you ever find yourself meandering through the garden watching and staring? It is not like suddenly the plants are going to grow before our eyes and pop out a tomato. I find myself observing my garden for hours each day with every now and then a picking of a rogue weed. And then maybe a douse of rainwater from the rainbarrel. But the rest of the time it is just watching and visualizing. I am one to always being envisioning what can I plant next year or how can I expand the garden and just a quick travel to the flower nursery makes me o so enthused. And every morning I check all my gardens, and while change is small such as a new bud or broken leaf, I find that I store the observations in the back of my mind. I am not sure what we expect when heading out each morning. Do we believe our little plants suddenly blossomed into pear trees? Gardening is a hobby just like coin collecting and such. I guess we value and appreciate the bounty of crops that we have raised almost like children. Pruning them, mulching them, giving water to them, monitoring their intake of sunlight, providing special nutrients; it almost seems like there is no end to outdoor work. Gardeners have a perception about them that allow them to analyze the slightest changes in their "environment." So back to the original question... Do you find yourself wandering through your garden waiting to see something grow only to find little to no change in your time spent observing?

"Regional Radar"

(Courtesy of NOAA)

"Regional Satellite"

(Courtesy of Penn State Meteo.)

"Regional Advisories"

(Courtesy of NOAA)

"Forecast Discussion" (Updated 5/10)
The tight pressure gradient will slowly begin to subside Sunday evening as the low pressure in Canada continues to trek northeastward. A weak ripple in the jet will feature a shortwave that may produce some light rain generally less than .1inches for late Monday into Monday evening. The best chances of QPF remain south of the commonwealth, but some rain is possible as far north as 10miles south of I-80. High pressure, 1024mb, moves in for Tuesday behind the wave along with some cooler air as a trough sits of the Northeast. H85s will drop to near 0C as far south as State College Tuesday, but May sunshine with diurnally drive temperatures to only (-1)-(-3)degrees below normal. Tuesday night will feature some intense radiational cooling with light winds, low RH values, and clear skies giving way to a possible freeze for the north and frost for the south. By Wednesday a cirrus deck of clouds will move in west to east with a return of a southwest flow ahead of the next storm system. H85s will return to +5C. A roaring low pressure heads up through the Great Lakes at 984mb with the best dynamics, but an open short wave and associated cold front will move across the Ohio Valley and Northeast. PWATs will be on the rise to several deviations above normal and winds aloft will be on the increase in the 500mb and 850mb levels. Some convection may form with a frontal rain band. There could be some severe weather as the warm sector will encompase the entire Northeast. But under a southerly flow some marine stable air may prevent strong surface instability from developing. QPF looks to be on the average of .5inches for much of the state with a Thursday frontal passage. High pressure moves into control for Friday, but not for too long as a weak stalled front keeps some unsettled weather for a few areas with partly to mostly cloudy skies and maybe light rain for late in the weekend. A strong cold front looks likely to move in early next week with possible severe weather chances across parts of the United States. Long term pattern shows warmer than normal temperatures with possible thunderstorm outbreaks with a somewhat active northern jet.

"Current Surface Map and Weekly History of Jet Stream Position"

(Courtesy of Weather Underground)

"Weekly Forecast" (Updated 5/10)
Monday- With high pressure in control for northern parts of the state, low dewpoints will allow colder valleys to reach below freezing for a possible light to moderate frost generally north of interstate 80. An alto-cumulus deck will move in across the southern portion of the state as a weak shortwave moves across Virginia. Most of the day will be generally pleasant as May sunshine will allow temperatures in the mid to upper 60s. But later in the day clouds may lower and thicken south of the Butler-Du Bois-State College-Wilkes Barre line for some possible light rain. Amounts will generally be up to a tenth of an inch and generally just be a nuisance. Rainfall amounts will also be scattered and some areas may see dry conditions. The best chance of rain is early evening. Gradual clearing will occur Monday night along with a return of a large bubble of high pressure. Any areas that see rainfall early in the evening may see some ground fog by morning as lows drop to dewpoint levels. Again some frost is possible across the north. Generally lows will be in the upper 30s to mid 40s.

Tuesday- After some morning light frost and 1-2mile visibility ground fog, sunshine will prevail under high pressure. Temperatures will stay near normal levels in the upper 60s to low 70s. Dewpoint levels though will be low and may cause an enhanced fire threat in the afternoon for the northern parts of the state. Winds will generally be light and from the north around 5-10mph. By evening skies will be clear with any diurnal cumulus soon dissapating. This night will be the coldest of the week with a possible freeze across the north and frost for the southern areas. Lows will range from the upper 20s in the northern valleys to mid 30s for the southern areas and upper 30s in the metropolitan areas.

Wednesday- Once again there will be a widespread frost for many areas followed by sunshine. A front will be approaching from the west and winds will turn southwesterly gusting to 15mph at times drawing up more humid and warm air. Dewpoints will rise into the 50s and low 60s for much of the day along with a bit of haze limiting visibility to 7miles at times. A few isolated thunderstorms are possible in the afternoon over the mountains thanks to orographic lift. Storms will be isolated at best. Highs will be back into the 70s for most areas and up to 75degrees near Philadelphia. Wednesday night will feature an increase in cirrus clouds particularily from west to east ahead of the next front. Lows will be mild an in the upper 40s to low 50s for most areas. Rainfall looks limited.

Thursday- The next cold front will be moving in from west to east. Partly to mostly cloudy skies will prevail over much of the state ahead of the associated rainfall. The southerly flow though may cause some low stratus for extreme southeastern areas. Highs will rise into the low to mid 70s with dewpoints rising into the low to mid 60s. Cumulus will begin to break out by early afternoon followed by a strato-cumulus sky. Thunderstorms and rain showers will move in with a frontal rain band. A few severe thunderstorms cannot be ruled out with a squall line with damaging winds as the primary threat. Towards evening high pressure moves in and may cause some fog to form overnight. Lows will not drop to much and will be in the 50s. Skies will gradually clear from west to east.

Friday- Friday will feature some possible morning dense fog with a return of sunshine by afternoon. The air behind the front will be drier but not much cooler. May sunshine should be able to boost highs into the 70s once again and possibly the upper 70s for parts of southeastern Pennsylvania in the cities. Friday night will feature mostly clear skies with relatively mild lows in the low to mid 50s.

"Wildfire Outlook" (Updated 5/10)
It could be a elevated fire week in store for parts of Pennsylvania under low humidity levels and dry conditions. A northwest flow will dominate the weather for the first half of the week. This will filter in some dry air with relative humditiy values down in the 20s and 30s for the parts of the day Sunday, Monday, and Tuesday. While after nearly 3inches of widespread rain from last week, the soil will dry out quickly thanks to the gusty winds featured this Sunday. Temperatures this week will stay on the normal to below normal side in the 60s and winds will begin to start to subside with gusts only up to 20mph or so by Monday so the overall official fire criteria will not be met. But still if little care is given while people are outdoors, it is possible for quick fire development and expansion. There have been reports in the upstate Pennsylvania area outside of Lock Haven in the Northcentral Mountains of many brush fires thanks to careless leave burners and campers. There is a chance for a slight bit of rainfall towards later in the week for Wednesday into Thursday, but this rainfall will be convective in nature and a bit more spotty. Also on Monday a weak shortwave may be able to produce a few light rain showers over the southcentral Pennsylvania region. Rainfall for the seven day period will likely be around .5inches for most of the state although there could be more or less thanks to the rainfall being more convective in nature and less unified than the past week's rainfall. Overall though the threat is only elevated a bit above normal and should not pose to many widespread fires. Natural fires will be hard to come by.

Here again are the fire criteria for development in Pennsylvania... Link.

Criteria for rapid initiation and spread of wildfires in PA:

1. Winds must be sustained at 15 mph (13 knots) for two hours or more, and

2. Minimum Relative Humidities (which usually occur in the afternoon) must be 30 percent or less, and

3. 10-hour Fuel Moistures must be 15 percent or less (and expected to remain there for two or more days).

"Fire Outlooks from Storm Prediction Center Days 1, 2, and 3"

(Courtesy of NOAA)

"Gardening Outlook" (Updated 5/10)
May is probably be my busiest month for planting. Now that we have just about reached mid month it is time to get all my annuals for pots and fill in areas in the ground with perennial plants. I try to shoot for a color scheme for most of my gardens. I like yellows, pinks, purples, suddle blues, but not brights reds or oranges. I also try to plant native plants in my garden that grow in Pennsylvania such as forest ferns. My vegetable garden is doing wonderful. All 28 lettuce plants ended up growing like wild and I have so much lettuce I do not know what to do with it all. In fact I have been giving quite a bit away making me the "popular neighbor," but I still have way to much lettuce. I planted four varieties... Romaine, Buttercrunch, Ithica, and Gourmet Bibb. I found that the Romaine was the fatest and easiest grower. My broccoli and cauliflower plants are about double their size since last Sunday and are growing very nice. I have yet to see any flowers yet, but the broccoli already seems to be getting a bit top heavy so I may have to stake them next weekend. I picked o about 40 scallion yellow and red onions. My method was to pick a yellow and red onion between another onion. This would allow for something similar to thinning and allow the onions left in the ground to mature while the ones I picked were used for scallions. My radishes are getting larger and soon will be ready for picking. My blueberry bushes are quite large with full foliage and many flowers. I have two different blueberry bushes that cross pollinate to allow for a more bountiful harvest. I added some mulch around the bushes to keep moisture nearby. I also added a bit of 10-10-10 fertilizer to the soil about 3inches from the main stem of the bushes. Last year the birds ate just about all my blueberries, so this year I am going to get bird proof netting to put around them before the berries ripen. My leeks are getting quite large along with the garlic, but they won't need to be picked until the tops turn brown. My snow peas are doing wonderful and getting quite large around my self-built trellis made of stakes and ties that resemble a jungle gym. My herbs are doing fine and I cut some chives for a chicken dinner the other night. I still believe it is too early for planting warm weather crops such as peppers and tomatoes. I plan planting them in late May or the 1st of June. I am also thinking of adding another raised bed box like my others possibly for the warm weather crops. It does appear this week there will be a little rain .05inches or less for southern Pennsylvania only on Monday and potentially up to .5inches for the entire state Wednesday night through Thursday night. Frosts are possible mainly for northern areas the first half of this week each night, but patchy frost cannot be ruled out for sheltered southern mountain valleys too. Remember to cover sensitive plants each night for the first half of the week.

"Soil Moisture Anomalies and 5-day Precipitation Amounts from Hydro Prediction Center"

(Courtesy of NOAA)

"Severe Weather Outlook" (Updated 5/10)
I am monitoring a chance of severe weather this week for the Ohio Valley and Northeast. A vigorous cold front will be ahead across the Midwest with a deep 984mb low across southern Canada. Warm southwesterly gusty winds near 25mph will draw up much warmer air with H85s rising above 10C. Cooler air aloft moves in with a trough for Friday. High helicity and shear values aloft with allow for nearly 60knots winds in the 0-8km spectrum. The lacking variable for everything is instability. Southerly winds will bring some marine layer airmass to parts of the region along with potentially thick cloud cover for some areas with a stratus deck. A few hundred j/kg of CAPE though should be able to develop across southern and western areas ahead of the cold front. Current models do show though some high +4 LI values which may inhibit some deep convection. The best dynamics remain well north of the region in Ontario and Quebec associated with the low center. But the low level jet should draw up some moist air and near 1.5inch PWATs. For now the threat looks to be somewhat controlled as instability looks elevated driven and not surface driven. But if the May sun is allowed to peak out a few stronger storms may develop with a frontal passage. Convection will likely be with a squall line if the situation becomes more imminent. Thursday looks to be the primary threat day. Looking beyond the 12z EURO is imminent for hot and humid weather to start by mid Month just as my monthly forecast pattern change indicated around mid Month. Chances for severe weather will begin to increase by mid month with the return of a favorable Bermuda High setup.

"Severe Weather Outlooks from Storm Prediction Center Days 1, 2, and 3"

(Courtesy of NOAA)

"Monthly Outlook" (May)
Well my April forecast verification looks just ok. My temperature forecast was spot on with near normal to above normal temperatures. Cooler conditions persisted early in the month, but by mid to late month an anomalous near heat wave definition for some areas hit rising the average monthly temperature for all climate reporting stations in the Keystone State. Temperatures averaged near 0-(+1.5) degrees for the month. Now my precipitation called for drier conditions, which did not pan out. Most areas ended up with about .5inches above normal in the rainfall department. Temperature forecasts always are much more uniformed than the at times unpredictable precipitation forecast. May looks to be a transition month for precipitation as the first half looks wet followed by a return of the average summer jet stream that looks to be this summer with trough in west, ridge in central US, southeast ridge, and weak trough in extreme Northern New England. My temperature call is for near normal to slightly above normal temperatures along with near normal precipitation for the month. The best chance of rainfall will be the first half of the month; also the warmest temperatures look to be towards the end of the month. Already the latest guidance is showing the summer jet stream pattern with MCS traveling through the Great Lakes and across just north of Pennsylvania. Latest EURO weeklies also support this. Here are the detailed predictions...

Temperature- Temperatures will be put on a cap for the first half of the month as cloud cover from rainfall will hold temperatures near normal. Soil moisture levels will be +1 deviation above normal. When soil moisture is below normal this allows boundary layer temperatures to be much warmer. Wet soil conditions tend to keep a hold on extreme hot temperatures. Later in the month the Bermuda high looks to nose in with a southerly flow drawing up very warm conditions with highs likely in the 90s several days this month.

Precipitation- Precipitation will be common for the first half of the month under a progressive flow. Precipitation may in fact average above normal the first half of the month. As the pattern transitions drier conditions will occur with only occasional thunderstorms outbreaks providing needed rainfall. The end of the stratiform rainfall will likely occur mid month. By the months end an above normal first half and below normal second half will lead to near normal precipitation. Although as we all know a two week period of dry weather does not at all show that we may have just had a wet four previous weeks.

"Temperature and Precipitation Outlooks from Climate Prediction Center for next 30 days"

(Courtesy of NOAA)

"Tropical Update" (Updated 5/10)
Well it is time to end the winter storm outlook section and replace it with my tropical section as we are entering the state of the tropical storm season which officially begins June 1. But as we have seen with the past, tropical storms and hurricanes can occur in May. I do not consider myself a tropical expert by any means as I have a limited knowledge, but this section is here for just my quick analysis that may be used while reading for convenience. Looking at the Atlantic SSTs it does appear the early in the year well below normal SST crisis has ended. The Gulf of Mexico is still a bit cooler than last year by the central Atlantic is warmer than last year at this time. There have been a few weak areas of showers and thunderstorms coming off the Africa coast, but nothing of any organization. As this pattern change occurs Mid May and the 2009 summer jet stream flow sets up, the GFS does show a few areas of concern in the tropics, but for now nothing is in the short or medium term and nothing should raise any eyebrows. Last year the first tropical storm occurred in June, so May is typically not a very active month. For now it seems intelligent to ignore the GFS fantasy storms and enjoy the quiet period in the tropics as we all know what happens when we get towards August and September. My forecast again is for a normal season as far as tropical storm and hurricane numbers go. I do think there will be a west based weak El Nino forming towards later in the season. Also a dominated Bermuda high should form and this may help to steer tropical systems out to sea. My areas of concern are in the southwest Gulf near the Texas and Mexico borders. Also I think a Florida hit may be possible earlier in the season. As for the east coast, if they were to face a tropical threat I would estimate the best time to be in early September as the jet becomes a bit more better oriented and the El Nino begins to develop, but overall the east coast threat looks lower than normal this year.

"Latest Tropical Systems including Sea Surface Temperatures"

(Courtesy of Wunderground)

"Here north of Harrisburg 2009 statistics"
(Severe Weather Stats...)
Severe Thunderstorm Watches- 1
Severe Thunderstorm Warnings- 0
Tornado Watches- 0
Tornado Warnings- 0
Total Thunderstorms- 3

(Precipitation Stats...)
Flood Watches- 1
Flood Warnings- 0
Monthly Precipitation- 2.49inches
Yearly Precipitation- 9.35inches

(Temperature Stats...)
Heat Advisories- 0
Excessive Heat Warnings- 0
90degree Days- 1
Highest Temperature- 92degrees

Weekly Forecast

Updated: 1:06 AM GMT on December 28, 2011

Permalink

Unsettled weather pattern...

By: Blizzard92, 10:50 PM GMT on May 02, 2009

"Afternoon Thoughts" (Updated 5/2)
Well it is just about that time of year, Summer. Full of outdoor activities, sports, laughing, swimming, vacations, and lawn mowing; yes lawn mowing. It amazes me every year how some people have no pride in the exterior appearance of one's home. In this modern age we care so much about the exterior of our appearances to the point of costly and dangerous surgery. Why do we not care about the place we spend the most time and best resemble who we are, our homes? I am sure all of you have that neighbor who doesn't mow their lawn for two-three weeks at a time and then when it is time to mow you park you front lawn chair in front of your house and watch the show. Weeds up to a foot high, dust flying in the air as the mower has problems chewing down the high grass. The occasional stalling of the mower and o so much more. And then we all seem to have that one neighbor who actually does mow their lawn on a regular basis, but does not have a shrub/tree/flower from here to Kalamazoo. Now you don't have to be an expert landscaper to have a nice exterior of the home, all it takes is a bit of elbow grease and a hop off the sofa into the hot summer sunshine. I guess this is all just one of many rants this time of year I have, and I know others share. Anyways, it looks like this week is going to feature an unsettled pattern, but the sun should be out at times. It reminds me of a typical week in April even though the calendar says May. May, wow it is hard to believe we are so far away from last winter. Why it seems like just yesterday everybody was watching every model run and holding their breath like there is no tomorrow. This time of year the weather is pretty benign, but once we head into June the next active weather begins, severe weather season. Enjoy the beauty and warmth of May and have a great day!!!

"Regional Radar"

(Courtesy of NOAA)

"Regional Satellite"

(Courtesy of Penn State Meteo.)

"Regional Advisories"

(Courtesy of NOAA)

"Forecast Discussion" (Updated 5/2)
Difficult forecast period as a stalled frontal boundary forms south of the Mason-Dixon line. Waves of low pressures will ripple along the front creating at times showers and thunderstorms through the next seven days. Model guidance appears a bit too pessimistic so I am straying away from that. The cold is farther south than progged located across the Tennessee Valley east into North Carolina. This will keep stratus clouds to the south of Pennsylvania through Saturday night as high pressure noses in from the north. Conditions will likely remain dry through Saturday night as cooler and drier air H85s dropping below 8C. But the front will lift a bit more northward during the later part of the day Sunday along with a complex of showers and thunderstorms. With LIs around +3 and meager elevated instability, thunderstorms will be possible but not common. PWATs will rise +1-3 standard deviations above normal along with H85s rising to near 10C. This will be enough to create a period of heavy rain south of I-80 towards Sunday evening and overnight through early Monday. Heaviest QPF will generally stay south of the State College Selinsgrove line with the highest numbers up to .75inches near the Maryland-Pennsylvania border. Occasional showers will be around Monday afternoon, but the majority of the heavier steady precipitation will be out of the region. This period will feature poor travel conditions with IFR and LIFR conditions at local airfields as ceilings drop to near 500ft and visibility drops to around 1-3miles at times. Conditions will improve as we head towards Monday night as high pressure drops south from the Canadian Maritimes with a 1024mb pressure. The frontal boundary should generally keep south of the region along with associated precipitation for a generally dry Tuesday with normal H85s around 8C. Some .01-.1inch QPF will be possible in the extreme south generally near Philadelphia. Sun may peak as with increasing inversion heights across areas north of I-80. The Monday night time frame may allow some dense fog to form right along the dry line somewhere just south of the I-80 corridor where they may see clearing skies after the Monday rainfall. This will generally be in western Pennsylvania for the most part. A clearing period looks like Wednesday with dry conditions and partly cloudy skies with H75 RH values relatively dry. Overnight Wednesday PWATS will be on the rise near 1.75inches with rising H85s near 12C across the southeast. This will allow moderate to heavy stratiform rain with perhaps some enhanced convective activity over the southeast thanks to being close to near the 1000mb surface low. Again this will bring a return to IFR conditions and low ceilings as low as 300ft. Cooler air blows in towards Thursday as the low moves northeast and becomes cutoff just north of Maine. This will keep a wet northwest flow with scattered rain showers with pea sized hail with freezing heights as low as 6000-7000ft. QPF looks meager for the rain showers only up to .1inches on average. Another stalled frontal boundary works over the region towards the weekend with unsettled conditions, but nothing overly impressive in the rainfall department.

"Current Surface Map and Weekly History of Jet Stream Position"

(Courtesy of Weather Underground)

"Weekly Forecast" (Updated 5/2)
Sunday- Departing high pressure over New England will allow the stalled frontal boundary to lift back northward again. Rising humidity levels along with a wave of precipitation will allow precipitation to initiate west to east over Pennsylvania towards afternoon and evening. Clouds will preclude any precipitation in the morning with a strato-cumulus deck. Clouds will lower towards afternoon with the approach of the rain. Rainfall amounts through evening will generally be light up to .25inches in extreme southwestern Pennsylvania. Highs will generally be in the low 60s with up to the upper 60s across northern Pennsylvania as they will be exposed to more sunshine. Sunday night will feature damp conditions south of I-80 with rainfall amounts averaging up to .5inches. The close amounts near .5inches will be for the Mason-Dixon Line locations. Lows will be cool as wet bulb cooling will have already dropped temperatures early in the evening. Lows will be in the upper 40s for the south and mid 40s for the north.

Monday- Monday looks relatively damp as a departing stratiform rain shield moves east and another one moves in for early afternoon. Total rainfall amounts for the day to not look to be anything impressive, generally near .25inches or so with higher amounts in the extreme south. Again rainfall will generally be south of northern Pennsylvania. As the rain moves west to east a few breaks in the clouds will occur in northwestern Pennsylvania by early afternoon with a slow progression eastward towards evening. High pressure will move into the region forcing the front back south again creating a generally dry evening. A few light rain showers may plague parts of extreme southeastern Pennsylvania in the evening. Highs will be near normal generally once again in the upper 50s to lower 60s with the higher numbers in the north thanks to the sunshine. Monday night will feature clearing especially in the north and west. Dense fog may form as high pressure creates light winds. This fog though will only be limited in areas that saw rainfall earlier in the day. Lows will be in the upper 40s statewide.

Tuesday- Tuesday creates a close call as the frontal boundary tries to stay far enough south of the region for an ok day. High pressure seems to want to push the rainfall to our south so it does appear that conditions will be partly to mostly cloudy statewide between systems. Rainfall if any will be confined to near the Maryland-Pennsylvania border with amounts only up to one tenth of an inch. Sunshine will be out for northern Pennsylvania. Highs will once again be in the lower 60s which will be kept in check thanks to somewhat overcast skies at times. Though for a forecast error, it would not take much to cause the boundary to lift northward for a damp day. Very close call. Towards Tuesday evening another weak storm system moves into the Ohio Valley under a southwest warming flow. Tuesday night looks dry for most of Pennsylvania though only with increasing clouds from west to east. Lows will be mild in the low to mid 50s statewide.

Wednesday- It appears the first half of Wednesday will be somewhat nice especially the eastern half of the state that is still under the control of the high pressure. Clouds will be moving into western Pennsylvania later in the day ahead of the Ohio Valley system. The flow will be from the southwest ahead of a trough and this will cause rising temperatures with highs relatively mild in the 70s statewide. A few upper 70s may be possible particularly in the eastern quarter of the state. Wednesday night will feature the return of poor traveling conditions as the next systems moves into the region. Rainfall will develop west to east throughout the night with perhaps some thunderstorms possibly strong in western Pennsylvania. Rainfall amounts should be manageable around .5inches at most. Lows will be in the mid 50s overnight with the rainfall.

Thursday- The front will likely cross the region during the day Thursday. I would watch out for some stronger thunderstorms as a vortex with high winds aloft moves over the region along with some enhanced instability. It looks to be just something just to monitor at this point. Rainfall will likely be associated with some form of frontal band and depending on convection will likely average amounts up to .25inches. Cooler air will move in behind the front during the day. Highs will generally be in the lower 70s statewide. The northwest flow returns overnight with slightly drier air but still a strato-cumulus deck over the region. Lows will be in the upper 40s.

Friday- Friday will feature pulse rain showers and thunderstorms as the low stalls to our northeast putting us in a westerly flow added by lake moisture and orographic lift. Pea sized hail will be possible with any of the heavier showers. Little temperature change will occur thanks to a Pacific air mass keeping highs in the lower 70s. Friday night will feature some early diurnal driven showers before only cloudy skies persist overnight. Precipitation amounts will generally be light and isolated.

"Wildfire Outlook" (Updated 5/2)
The flow appears generally unsettled throughout the seven day period as RH values will be high thanks to the southerly flow. But a large boundary will exist over the I-80 corridor early in the week between rain showers and partly cloudy skies with drier air. This may pose an enhanced fire weather threat over extreme northern Pennsylvania as conditions there will be dry. But towards midweek RH values will surge and winds will be lightning up. Rainfall will overspread much of the region midweek. Then towards the end of the week the flow remains unsettled with occasional rain showers. Groundwater and soil moisture levels for the short term look wet. Winds will be generally light most of the week and temperatures will be near normal. Overall the fire threat is limited.

Here again are the fire criteria for development in Pennsylvania... Link.

Criteria for rapid initiation and spread of wildfires in PA:

1. Winds must be sustained at 15 mph (13 knots) for two hours or more, and

2. Minimum Relative Humidities (which usually occur in the afternoon) must be 30 percent or less, and

3. 10-hour Fuel Moistures must be 15 percent or less (and expected to remain there for two or more days).

"Fire Outlooks from Storm Prediction Center Days 1, 2, and 3"

(Courtesy of NOAA)

"Gardening Outlook" (Updated 5/2)
My vegetable garden is doing just wonderful with this rain followed by sunshine followed by more rain. Also temperatures are right where they are supposed to be. This week looks to feature occasional periods of rain with a week total of near 1.5inches for the next seven days. Watering does not appear necessary at all this week. Soil moisture anomalies will stay above normal also. Temperatures will be warm enough to inhibit any frost from forming statewide so this week you will not have to worry about covering some of your more touchy plants. I have really noticed a dramatic growth in my broccoli and cauliflower plants. The broccoli plants appear to be getting a bit top heavy so I might have to stake them a bit later this week. I added my one and only application of 10-10-10 fertilizer. I apply it extremely lightly to my beds particularly around my blueberry bushes will have full foliage now and many buds and white flowers. I only apply fertilizer before the summer season starts and I apply one more dosage a few weeks after I put in my warm weather crops. I likely will not be planting my warm weather vegetables until late May or early June. I am thinking a bit about building another raised bed box as I have had such success with the other raised boxes. These raised beds allow me to choose my own soil composition. Also weeds are less likely to grow and it makes it difficult for animals to get in them. And finally the warm sun heats the boxes faster the soil at ground level so this extends the growing season for some crops. I have had some plants in the boxes since mid March! The two crops I was worried about growing this season, celery and garlic, are growing great or they appear so at least. The only plant I have added within the last seven days is a cilantro herb plant. It appears my first harvest of lettuce can occur any day now and my first scallion onions will be within a week or two. My radishes are about two weeks from harvest also. Everything else is more than two weeks from harvest. I tried planting spinach seeds again this year and once again they grow at a snail's pace. Has anyone had any luck with them before? My neighbor bought actual spinach plants and they are growing like beauties, but everytime I go to a nursery I cannot find the actual plants. Well now sightings of my leaping gazelle like groundhog within two weeks, knock on wood. I did place a chicken wire fence now around my garden that is ground level just to be on the safe side too.

"Soil Moisture Anomalies and 5-day Precipitation Amounts from Hydro Prediction Center"

(Courtesy of NOAA)

"Severe Weather Outlook" (Updated 5/2)
I do not see this week as a big severe weather week for the Northeast, but I do have my eyes turned towards late Wednesday for western Pennsylvania and Thursday for the rest of the state. Ahead of the cold front in the right front quadrant lies Pennsylvania in the warm sector. A strong disturbance will role across the region with a vortex of 60knot winds aloft over much of the Northeast. With the steep lapse rates and possible elevated instability, any strong May sunshine may allow a few strong to severe thunderstorms to form. The threat does not look overly high thanks to timing Wednesday night and the widespread stratus overcast skies, but the potential is there. The highest threat would be in western Pennsylvania with a squall line associated with the frontal rain band. The threat levels diminished slightly as one moves east. Boundary layer dewpoints and RH values look somewhat high along with temperatures in the 70s. So stay tuned throughout the week for more updates. As for anything else occasional thunderstorms are possible throughout the week with any of the waves of low pressure rotating along the frontal boundary. The best chance of severe weather this week looks to be over the southern US. But heading in towards next week the active jet shifts northward possibly bringing some severe weather to the Central Plains and South Great Lakes.

"Severe Weather Outlooks from Storm Prediction Center Days 1, 2, and 3"

(Courtesy of NOAA)

"Monthly Outlook" (May)
Well my April forecast verification looks just ok. My temperature forecast was spot on with near normal to above normal temperatures. Cooler conditions persisted early in the month, but by mid to late month an anomalous near heat wave definition for some areas hit rising the average monthly temperature for all climate reporting stations in the Keystone State. Temperatures averaged near 0-(+1.5) degrees for the month. Now my precipitation called for drier conditions, which did not pan out. Most areas ended up with about .5inches above normal in the rainfall department. Temperature forecasts always are much more uniformed than the at times unpredictable precipitation forecast. May looks to be a transition month for precipitation as the first half looks wet followed by a return of the average summer jet stream that looks to be this summer with trough in west, ridge in central US, southeast ridge, and weak trough in extreme Northern New England. My temperature call is for near normal to slightly above normal temperatures along with near normal precipitation for the month. The best chance of rainfall will be the first half of the month; also the warmest temperatures look to be towards the end of the month. Already the latest guidance is showing the summer jet stream pattern with MCS traveling through the Great Lakes and across just north of Pennsylvania. Latest EURO weeklies also support this. Here are the detailed predictions...

Temperature- Temperatures will be put on a cap for the first half of the month as cloud cover from rainfall will hold temperatures near normal. Soil moisture levels will be +1 deviation above normal. When soil moisture is below normal this allows boundary layer temperatures to be much warmer. Wet soil conditions tend to keep a hold on extreme hot temperatures. Later in the month the Bermuda high looks to nose in with a southerly flow drawing up very warm conditions with highs likely in the 90s several days this month.

Precipitation- Precipitation will be common for the first half of the month under a progressive flow. Precipitation may in fact average above normal the first half of the month. As the pattern transitions drier conditions will occur with only occasional thunderstorms outbreaks providing needed rainfall. The end of the stratiform rainfall will likely occur mid month. By the months end an above normal first half and below normal second half will lead to near normal precipitation. Although as we all know a two week period of dry weather does not at all show that we may have just had a wet four previous weeks.

"Temperature and Precipitation Outlooks from Climate Prediction Center for next 30 days"

(Courtesy of NOAA)

"Tropical Update" (Updated 5/2)
Well it is time to end the winter storm outlook section and replace it with my tropical section as we are entering the state of the tropical storm season which officially begins June 1. But as we have seen with the past, tropical storms and hurricanes can occur in May. I do not consider myself a tropical expert by any means as I have a limited knowledge, but this section is here for just my quick analysis that may be used while reading for convenience. Looking at the Atlantic SSTs it does appear the early in the year well below normal SST crisis has ended. The Gulf of Mexico is still a bit cooler than last year by the central Atlantic is warmer than last year at this time. There have been a few weak areas of showers and thunderstorms coming off the Africa coast, but nothing of any organization. As this pattern change occurs Mid May and the 2009 summer jet stream flow sets up, the GFS does show a few areas of concern in the tropics, but for now nothing is in the short or medium term and nothing should raise any eyebrows. Last year the first tropical storm occurred in June, so May is typically not a very active month. For now it seems intelligent to ignore the GFS fantasy storms and enjoy the quiet period in the tropics as we all know what happens when we get towards August and September. My forecast again is for a normal season as far as tropical storm and hurricane numbers go. I do think there will be a west based weak El Nino forming towards later in the season. Also a dominated Bermuda high should form and this may help to steer tropical systems out to sea. My areas of concern are in the southwest Gulf near the Texas and Mexico borders. Also I think a Florida hit may be possible earlier in the season. As for the east coast, if they were to face a tropical threat I would estimate the best time to be in early September as the jet becomes a bit more better oriented and the El Nino begins to develop, but overall the east coast threat looks lower than normal this year.

"Latest Tropical Systems including Sea Surface Temperatures"

(Courtesy of Wunderground)

"Here north of Harrisburg 2009 statistics"
(Severe Weather Stats...)
Severe Thunderstorm Watches- 1
Severe Thunderstorm Warnings- 0
Tornado Watches- 0
Tornado Warnings- 0
Total Thunderstorms- 3

(Precipitation Stats...)
Flood Watches- 1
Flood Warnings- 0
Monthly Precipitation- 2.49inches
Yearly Precipitation- 9.35inches

(Temperature Stats...)
Heat Advisories- 0
Excessive Heat Warnings- 0
90degree Days- 1
Highest Temperature- 92degrees

Weekly Forecast

Updated: 1:06 AM GMT on December 28, 2011

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About Blizzard92

Cornell University- Atmospheric Sciences Student; Central PA SKYWARN Storm Spotter; American Meteorological Society Member; PA CoCoRaHS Branch Member

Local Weather

Scattered Clouds
45 °F
Scattered Clouds

Personal Weather Stations

Linglestown, PA
Elevation: 520 ft
Temperature: 24.2 °F
Dew Point: 15.2 °F
Humidity: 68%
Wind: Calm
Wind Gust: 9.0 mph
Updated: 10:37 AM EST on January 18, 2014

About Personal Weather Stations