Major Lake Effect Snow Outbreak...
"Lake Effect Outbreak of December 5-9th"
A multi-day extended northwest, cyclonic flow will cause a large lake effect snow outbreak over much of the Pennsylvania/Maryland snowbelts. Additionally the long fetch may cause several coatings to a light accumulation downwind of the Appalachians. A weak shortwave (Alberta Clipper) is currently moving well south of the Middle Atlantic. This is causing a large area of light to moderate snowfall over West Virginia, southern Virginia, and parts of North Carolina. This will cause some weak upper level ridging over the northern Middle Atlantic with an area of subsidence. This will bring a quick end to the lake effect snow showers for the first half of Saturday night despite a steady northwest flow. Lows Saturday night won't drop too much with some stratocumulus cloud cover and 5-10mph winds mixing the surface. The clipper will move offshore by late Saturday and redevelop as a relatively strong 1000mb coastal low. The low will undergo rapid cyclongenesis, but several hundred miles well off the coast. The low will deepen to 976mb by late Sunday and begin to retrograde towards Nova Scotia and the Gulf of Maine. The 968mb low will track northwest into Nova Scotia scraping parts of the northern half of Maine with a moderate snowfall. This retrograding, cutoff low will set the stage for a dominant cyclonic flow over the entire Northeast. 700mb RH values indicate increasing humidity values aloft by Sunday morning under a 310 degree trajectory. Organized snow bands will begin to develop downwind of Lake Erie across northwestern Pennsylvania. GFS bufkit indicates convective temperatures being reached by mid morning for most areas on Sunday allowing for daytime instability to fuel cellular snow showers over the rest of western and central Pennsylvania. Across the Laurel Highlands, moderate orographic lift, upslope snow will begin with daytime accumulations around 1-4in. Initially the bands over northwestern Pennsylvania will be relatively light, but increase in intensity with better dendritic growth and excellent Omega values later in the day. MOS guidance indicates highs below freezing for many areas with mid to upper 30s elsewhere for the entire northern Middle Atlantic. But looking at the H85 thermals at nearly -10C, MOS/MAV may be running a bit too warmer. I would tad highs lower just a degree or two especially considering any evaporational cooling from snow showers and widespread stratocumulus cloud cover.
By late Sunday afternoon, a tightning pressure gradient and strong atmospheric mixing will promote increasingly gusty winds. Winds at the surface may gust upwards of 30-35mph during the day with advisory criteria winds along the ridgetops of nearly 50-55mph especially in the Laurel Highlands and across western Maryland. Increasing moisture from the Great Lakes will continue to feed and strengthen the lake effect snow bands over northwestern Pennsylvania. By Sunday evening the flow will migrate to a 320 trajectory promoting a clear Huron-Erie connection allowing for long-extensive bands well inland across the Alleghanies. With gusty winds and falling temperatures by Sunday evening, near blizzard conditions will occur across the snow belts with blowing and drifting snow as visibility drops to near zero. Snowfall rates will increase to nearly 1-2in per hour in the heaviest bands. Monday will feature the passing a weak vortex of energy just north of Pennsylvania. This will increase the instability allowing for the heaviest of snow bands to fall Monday. Guidance also suggests widespread flurries and snow showers over much of Pennsylvania, western Maryland, and northern Maryland near the Mason-Dixon line. As the vortex passes by, high resolution models indicate a dominant lake effect band forming from Meadville to Du Bois to Philipsburg to State College and possibly as far south as Harrisburg. This common 322 streamer is most likely at some point Monday or Monday night and may cause light snow accumulations even into the Lower Susquehanna Valley of central Pennsylvania. The setup reminds me a bit of November 2008 when a vortex of energy passed through Pennsylvania allowing for a long lake effect snow streamer to reach well across Pennsylvania. Link. Exact placement and development of this band still remains highly uncertain. Monday evening will continue the upslope moderate to heavy snow over the Laurel Highlands with bands over northwestern Pennsylvania stretching southeast. Also this northwest flow will favor lake effect streamers from Ontario reaching southward across the Finger Lakes Region down into northeastern Pennsylvania. Some areas in northern Susquehanna and Wayne Counties may see 3-5in by mid week. Upslope snows will also occur in the Poconos. I have found often the Mt. Holly radar is not sensitive enough to pick up on the accumulating snows over the Poconos in lake effect situations when in fact they can receive 1-3in. H85s will drop to nearly -13C by Tuesday and Wednesday with advecting drier air. Lake effect snows will decrease in areal coverage, but continue to add light snow accumulations.
Total snow accumulations will be highly variable as typical with lake effect snow. Areas across the plateau of southern Erie county and Crawford county will likely see the highest accumulations, 12-24in, with isolated 30in areas. Across the Laurel Highlands and western Maryland upslope totals will be on the order of 6in to possibly over one foot especially for favored areas in southern Somerset County near Laurel Summit and Mt. Davis. Northeastern Pennsylvania will see 1-4in with the Poconos having similar amounts. Across the Pittsburgh metro area, midweek cumulative totals will be also 1-4in. For the ridge and valley region into east central Pennsylvania accumulations will not be widespread, but patchy coatings to two inches+ are possible in isolated areas. By Wednesday high pressure will take control slowly bringing an end to the extended snows, high winds, and widespread stratocumulus deck. Most of the week will be typical of a northwest flow with highs only reaching above freezing across Maryland, Delaware, and extreme southern Pennsylvania.
A quick look at the progression of the banding... High resolution NMM and NAM models show two dominant bands for late Sunday one from Erie County to Forest County to Clearfield County. The second band a bit farther south into Butler County stretching into the Laurel Highlands. Both bands show Huron-Erie connections. Then it appears a dominant band forms towards Monday or Monday night along rt 322/22 possibly stretching as far south as east-central Pennsylvania. These bands will the heaviest producing for accumulations over northwestern Pennsylvania. The Laurel Highlands will generally see upsloping snows with embedded heavier bands. Also a few streamers may stretch from Ontario into northeastern Pennsylvania.
"Current Lake Erie Wind Direction and Speed"
(Courtesy of NOAA)
"Current Lake Erie Water Temperature"
(Courtesy of NOAA)
"Lake Effect Snow Impacts"
1. Steady due northwest 310-320 degree flow
2. 20-25F land/water temperature contrast along lake shore
3. Extended four to five days of organized bands
4. Possibility for a few bands to extend into Ridge and Valley Region of Pennsylvania with C-2in of snow
5. Heaviest accumulations in higher elevations of southern Crawford and Erie counties up to 25-28in of snow.
"Regional Radar"
(Courtesy of NOAA)
"Regional Advisories"
(Courtesy of NOAA)
"Selected City Accumulations"
Erie- 10-15in with higher amounts southeast of the city (12-24in)
Meadville- 10-15in of snow
Bradford- 8-14in of snow
Butler- 3-5in of snow
Pittsburgh- 1-4in of snow
Latrobe- 2-5in of snow
Indiana- 3-6in of snow
Johnstown- 9-15in of snow
Somerset- 8-14in of snow
Altoona- 2-4in of snow
Du Bois/Clearfield- 3-6in of snow with locally higher amounts
Philipsburg- 3-5in of snow
State College- 1-4in of snow
Lock Haven- 2-4in of snow
Williamsport- Locally 1-3in of snow
Mt. Pocono- 1-4in of snow
Selinsgrove- Locally 1-3in of snow
Harrisburg- C-2in of snow
Hagerstown- Locally C-2in of snow
Cumberland- 1-3in of snow
Frostburg- 4-8in of snow
McHenry- 6-12in of snow
Oakland- 7-14in of snow
"Snow Map"
*This will be a long duration snow event. These forecasted snow totals are a cumulative snow total forecast over the four to five day period. Also areas downwind of the forecasted 1-3in of snow will see spotty coatings to two inches.
"Here northeast of Harrisburg 2010-2011 winter statistics"
(Snow Stats)
Current Snow Cover- Trace
Monthly Total (November)- Trace
Monthly Total (December)- 0.5in
Seasonal Total- 0.5in
Winter Weather Advisories- 0
Winter Storm Warnings- 0
Ice Storm Warnings- 0
Blizzard Warnings- 0
Freezing Rain Advisories- 0
Winter Storm Watches- 0
(Temperature Stats)
Lowest High Temperature- 30.5F
Lowest Low Temperature- 15.3F
Wind Chill Advisories- 0
Wind Chill Warnings- 0
(Snow Storms Stats)
First accumulating snow- December 10 0.50in
"Local Harrisburg Radar"
(Courtesy of WGAL)
Reader Comments
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ECMWF model gives us about a 48 hour period of northeast winds with heavy synoptic precip. This could be a very significant snow event for my location instead of areas to my east near Marquette and Munising favored by northwest winds.
With the further west low track, we will have to watch for possible low pressure wave development along the front across the eastern US also.
Sadly, it's looking that way right now...I expect mostly rain here in NYC.
Actually it seems a new band is forming over altoona west and moving somewhat northeasterly. Hopefully it gathers some strentgth soon.
Clinton county, PA, just NNE of State College must have a nice accumulation by now. Pretty intense streamer has been training over that county most of the day it seems. Looks like that one is starting to very slowly drift south now.
Ahh, that's better.
It's Tuesday... lol
PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
831 AM EST TUE DEC 07 2010
VALID 12Z SAT DEC 11 2010 - 12Z TUE DEC 14 2010
...MAJOR STORM TO AFFECT THE CENTRAL AND EASTERN UNITED STATES...
PRELIMINARY UPDATE...
USED THE 00Z ECENS MEAN EXCLUSIVELY TO UPDATE THE PRELIMINARY
FRONTS AND PRESSURES FOR DAYS 3 THROUGH 7 ACROSS THE UNITED
STATES. THERE IS A DISCONCERTINGLY EVEN DIVIDE IN THE GUIDANCE AS
TO THE LATITUDE ALONG WHICH THE MAJOR SYNOPTIC CYCLONE CROSSING
THE CENTRAL AND EASTERN STATES TRACKS DURING THE FORECAST PERIOD.
THE SPLIT INCLUDES BOTH DETERMINISTIC SOLUTIONS AND INDIVIDUAL
ENSEMBLE MEMBERS FROM THE VARIOUS MODELING CENTERS. THE 00Z ECMWF
REPRESENTS THE NORTHERN EDGE OF THE GUIDANCE...WITH THE 00Z GFS
TAKING UP THE SOUTH SIDE. THE GEM GLOBAL SIDES WITH THE
ECMWF...WITH THE UKMET CLOSER TO THE GFS. THE GEFS MEAN...ECENS
MEAN...AND CMCE MEAN ALL SPLIT THE DIFFERENCE...WITH THE
INDIVIDUAL ENSEMBLE MEMBERS COMPRISING THE MEANS STRUNG OUT
ALONG...NORTH...AND SOUTH OF THE TRACKS OF THE MEAN SURFACE LOWS.
SUCH A ROBUSTLY EVEN DIVISION IN THE SOLUTIONS ESSENTIALLY
NECESSITATES USING A MEAN TO CREATE THE MANUAL PROGS...AND
CONSIDERING THE ECENS MEANS STABILITY OVER THE PAST SEVERAL
RUNS...FELT THAT GUIDANCE AFFORDED THE SAFEST BET. THE DIFFERENCE
IN LATITUDE OF THE LOW TRACK WILL DETERMINE HOW MUCH MORE OF THE
NATION IS AFFECTED BY WINTRY PRECIPITATION...AND OF COURSE WHERE
THE HEAVIEST PRECIPITATION OCCURS.
NWUS53 KMQT 071604
LSRMQT
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MARQUETTE MI
1103 AM EST TUE DEC 07 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0730 AM SNOW 6 SSE MARQUETTE 46.47N 87.37W
12/07/2010 M14.8 INCH MARQUETTE MI NWS EMPLOYEE
STORM TOTAL SINCE SATURDAY EVENING. 5.7 INCHES IN THE
LAST 24 HOURS. STILL SNOWING.
That's not a secondary, that's the primary low that remains dominant.
I'm the same way. Given the set-up, if you put a gun to my head right now I'd say Wintry Mix. However we got almost a week to go, still.
To Miller B or not to Miller B, that is the question?
A storm destined to dump heavy snow over portions of the Plains, Midwest and Northeast this weekend could solidify a white Christmas for these areas and others.
Weekend Monster Storm
When push comes to shove, a wintry mix followed by rain seems to be the most likely option at this point for the I-95 Northeast and the I-64 corridor in the Midwest.
Even so, the track is still questionable, and people are advised to keep checking in at AccuWeather.com in the coming days.
For now, AccuWeather.com meteorologists are not buying the idea of a storm cutting up to the western Great Lakes, bringing overwhelming warmth to the interior Northeast or a blizzard for the Upper Midwest.
The "warm up and rain I-95 forecast" is based on a double-storm scenario with one center rolling eastward across the central Plains to the Ohio Valley Saturday, where it weakens, followed by a second storm forming along the East Coast and moving northward Sunday.
In short, the scenario allows warmer air to invade much of the immediate Ohio Valley and northern Atlantic Seaboard at the critical time to avoid heavy snow accumulation.
Cities in the warm-up and rain scenario include: Louisville, Nashville, Richmond, Washington, D.C., Baltimore, Philadelphia, New York City, Boston and Portland, Maine.
Even with this warm scenario, a zone of moderate to heavy snow will stretch eastward from the central Plains to the lower Great Lakes and the interior Northeast.
Chicago, Indianapolis, Detroit, Cleveland, Buffalo, Ottawa, Toronto and possibly Pittsburgh and St. Louis would get enough snow to survive up until Christmas from this single storm.
Burlington, Montreal, Albany and Scranton are on the bubble with this storm, meaning a wintry mix or perhaps a change to rain at the height.
Travelers can entertain their worst fears, while skiing interests conjure up their wildest dreams.
If you are in the sweet spot of the storm, just west of the wintry mix area, from 1 to 2 feet could pile up with strong wind.
Away from the infamous rain/snow line, an all-out blizzard could pound part of the central Appalachians, eastern Great Lakes and neighboring southern Ontario and western Quebec.
We wish to remind you at this point that these are merely lines in cyberspace and the forecast could change, if the storm track changes.
FINAL...
UNFORTUNATELY...THE BALANCE OF THE MODELS HAS NOT CHANGED WITH THE
12Z CYCLE. THE GFS HAS COME SLIGHTLY NORTHWARD WITH THE TRACK OF
THE MAIN SURFACE LOW AS IT APPROACHES THE APPALACHIANS...BUT THE
GEFS MEAN HAS COME A HAIR SOUTH. THE UKMET CONTINUES ITS SOUTHERN
TRACK...KEEPING THE SPLIT FLOW SEPARATE OVER EASTERN NORTH
AMERICA. THE GEM GLOBAL IS STILL TO THE NORTH...WITH MORE
NORTHERN STREAM INTERACTION. WILL STICK WITH THE MEAN USED FOR
THE UPDATE PACKAGE...WHICH CONTINUES TO BE THE COURSE OF LEAST
REGRET. MORE CERTAIN IS THE INVASION OF MODIFIED ARCTIC AIR IN
THE WAKE OF THE BIG EASTERN WAVE...WITH NORTH WINDS DRIVING SOME
OF THE COLDEST AIR OF THE SEASON SO FAR DEEP THROUGH THE EASTERN
STATES AND DOWN THE FLORIDA PENINSULA BY THE END OF THE PERIOD.
MJO is still in phase 4 or 5 which is why it is still unfavorable for heavy snowstorms.
Attention PHL/BWI/DCA folks: No matter how much Accu Weather will hype this next storm as snow, it will be RAIN for I95 cities. Snow for MIDWEST locations, including PIT/Western NY
Washington National Partly Sunny 34 10 37 W23G31 29.80S
Dulles Intl. Mostly Sunny 32 9 38 W23G32 29.79S
BWI Airport Partly Sunny 33 13 43 W21G29 29.74S
Hourly observations from: 200 PM EST TUE DEC 07 2010
Ha. This guy would be banned from Accuweather's forums for "bittercasting".
Oh yeah. He hates Accu Weather with a passion.
So do I. They banned me last winter or the one before for cracking down on this moron who thought every storm to even possibly crop up would put 9 feet of snow in his backyard. Artards.
Every once in a while they will be correct and therefore feel justified in freaking people out while exciting others.
Here's the chase footage from the lake effect snow chase Winterstormsblog and I went on Dec. 5, 2010. Footage includes videos and photos!
Awesome job Charles. Great videos.
My family and boss might be a bit pissed but who cares. Let's hit the Tug Hill Plateau. I have a cam I look at there and they're up to 3 feet on the ground when I last looked. I wish I could...
I would if it were snowing here in Springfield! I would also like to see snow on the ground back home, but i don't think that's going to happen either
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