Lee drenching the Gulf Coast; Katia a Cat 2

By: Dr. Jeff Masters , 3:31 PM GMT on September 04, 2011

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Tropical Storm Lee made landfall on the southern coast of Louisiana near 4 am CDT this morning, and continues to inch slowly northward and dump very heavy rains. The storm is not a threat to intensify, since its center lies over land, but enough of the storm's circulation is over water that Lee will be slow to weaken. At New Orleans Lakefront Airport, 8.85" inches of rain had fallen from Lee as of 9 am CDT this morning. Top winds this morning hit 46 mph, gusting to 57 mph, at 6:28 am CDT, when a heavy squall blew in. Latest satellite loops show Lee has lost quite a bit of its heavy thunderstorms since yesterday, but the storm remains a formidable rain-maker. Lee brought a storm surge of 4 feet to New Canal Station in Lake Pontchartrain and at Shell Beach east of New Orleans yesterday afternoon. NOAA's Storm Prediction Center reported eight probable tornadoes from Lee yesterday. These tornadoes damaged approximately ten buildings, but caused no deaths or injuries.


Figure 1. Observed rainfall for the seven-day period ending at 8 am EDT Sunday Sep 4, 2011. Tropical Storm Lee had dumped 5 -10 inches of rain over a large swath of the coast, with a few areas in excess of ten inches (pink colors). Image credit: NOAA/AHPS.


Figure 2. Predicted rainfall for the 5-day period 8am EDT Sunday - 8 am EDT Friday, Sep 9, 2011. Lee is expected to bring a large swath of 4+ inches of rain all the way to the mid-Atlantic. Image credit: NOAA/HPC.

Forecast for Lee
Lee's large size and slow movement will make heavy rains the main concern today. Later in the week, the remnants of Lee's may be a problem for the mid-Atlantic and Northeast, where recovery efforts from the devastating flooding due to Hurricane Irene may be hampered by an additional 2 - 3 inches of rain. Tornadoes from Lee are a potential hazard today, as NOAA's Storm Prediction Center is highlighting the Northern Gulf Coast in their "slight risk" area for severe weather. A tornado watch is posted for the region, but no tornadoes have been reported as of 9 am CDT.

Hurricane Katia
Hurricane Katia finally overcame the wind shear and dry air interfering with it, and intensified into a Category 2 hurricane with 100 mph winds this morning. Latest satellite loops show a well-defined eye for the first time, but the hurricane still has a lopsided appearance, due to he impacts of dry air and moderate wind shear of 10 - 20 knots on its southwest side.

Katia will not pose a danger to any land areas over the next five days, but may be a threat to the U.S. late this week. The computer models disagree considerably on the position and strength of a trough of low pressure that will develop over the Eastern U.S. late this week, and thus how Katia will be steered. The evolution of this trough will be strongly affected by Tropical Storm Lee, and the models are not very skillful at predicting transitions from tropical storm to extratropical storm, which will happen to Lee by Wednesday this week. We have two of our reliable models--the ECMWF and UKMET--predicting that the trough will form farther west, steering Katia very close to North Carolina late this week. The rest of the models predict a more easterly position of the trough, which would force Katia to turn northwards towards Canada well before reaching North Carolina. Either scenario is possible, and it will probably be at least another day before the models converge on a solution for the long-term fate of Katia. It's likely that locations on the U.S. coast south of North Carolina will not receive a direct hit from Katia, but the entire coast from North Carolina northwards to New England and Canada's Maritime Provinces is definitely at risk. Long period swells from Katia will begin affecting the Bahamas tonight, then reach the Southeast U.S. by Monday morning. By Tuesday morning, the entire U.S. East Coast will see high surf from Katia, and these waves will increase in size and power as the storm grows closer. Given the slow movement of Katia as it approaches the coast, plus its expected Category 1 to 3 strength as it approaches, the storm will probably cause extensive beach erosion and dangerous rip tides for many days.


Figure 3. Morning satellite image of Hurricane Katia.

Elsewhere in the tropics
This week and next week typically mark the two most active weeks of the Atlantic hurricane season, and there are two potential threat areas we need to watch. The GFS model predicts that a tropical depression could form in the southern Gulf of Mexico's Bay of Campeche by Friday or Saturday this week. Several other models give support to this idea, and predict such a storm would track northwards or north-northeastwards towards the northern Gulf Coast between Louisiana and the Florida Panhandle. The other region to watch is between the Lesser Antilles and the coast of Africa. The NOGAPS model is predicting that a tropical wave currently near the coast of Africa could develop into a tropical depression late this week, and arrive in the northern Lesser Antilles by Saturday or Sunday.

Jeff Masters

Tropical Strom Lee (taco2me61)
This is what happens when you do not tie up your boat.... This was taken in Pass Christian MS
Tropical Strom Lee

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Quoting TropicalAnalystwx13:
Good Morning WUpeople!

Katia is strengthening right now, should be 110 mph at 11AM IMO...ATCF just updated and says the same.



Our new invest, 95L, looks promising...Unlike Katia, it is in a favorable environment, and should take a farther south track. This is a definite Lesser Antilles threat, including Puerto Rico. This may change however, and it could go north or south.



We need to watch the Gulf of Mexico over the coming week, models are still showing tropical cyclone development and a Gulf Coast threat.


Pretty interesting season. Can't compare it to anything else.
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Quoting TropicalAnalystwx13:
Good Morning WUpeople!

Katia is strengthening right now, should be 110 mph at 11AM IMO...ATCF just updated and says the same.



Our new invest, 95L, looks promising...Unlike Katia, it is in a favorable environment, and should take a farther south track. This is a definite Lesser Antilles threat, including Puerto Rico. This may change however, and it could go north or south.



We need to watch the Gulf of Mexico over the coming week, models are still showing tropical cyclone development and a Gulf Coast threat.


katia really looks like adoughnut haha
Member Since: June 17, 2011 Posts: 11 Comments: 6439
2337. Relix
I say it forms faster than expected and eventually affects or gets close tot he NE Caribbean. Of course it needs to gain strength now.
Member Since: August 3, 2006 Posts: 0 Comments: 2639
Quoting jpsb:
I think at this point we are making our own weather, Texas, Oklahoma and parts of surrounding states are so hot and dry that they heat and dry out any air mass that moves over head. hoping we can erode the high slowly with cool damp air, just wondering where the cool damp air is going to come from?


A Canadian airmass sometime around November...
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Quoting wunderweatherman123:
teddy 0z ECMWF shows 95L not developing until getting into the carribean. 997mb west of jamaica..


I'm aware. All models are showing that it won't develop for a while.
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Good Morning WUpeople!

Katia is strengthening right now, should be 110 mph at 11AM IMO...ATCF just updated and says the same.



Our new invest, 95L, looks promising...Unlike Katia, it is in a favorable environment, and should take a farther south track. This is a definite Lesser Antilles threat, including Puerto Rico. This may change however, and it could go north or south.



We need to watch the Gulf of Mexico over the coming week, models are still showing tropical cyclone development and a Gulf Coast threat.

Member Since: July 6, 2010 Posts: 108 Comments: 30245
Quoting CybrTeddy:
Watch this area, VERY closely. The GFS & ECMWF both develop this into a tropical cyclone. Also, 95L has good model support but not until for a while. Meaning, don't expect the chances to go up for it anytime soon.
teddy 0z ECMWF shows 95L not developing until getting into the carribean. 997mb west of jamaica..
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The Bailey fire burned north of Interstate 10 on Sunday. (Photo by Clara Fowler, for the Chronicle) Photo: For The Chronicle, Clara Fowler



Katy Texas fire (Under control now, Sparked by power lines)
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guys ecmwf develops 95L in the carribean looks like he is the "southern wave" the models showed..
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2330. jpsb
Quoting DFWjc:


And look at that dry air coming back in from the north, Texas just can't win right now....
I think at this point we are making our own weather, Texas, Oklahoma and parts of surrounding states are so hot and dry that they heat and dry out any air mass that moves over head. hoping we can erode the high slowly with cool damp air, just wondering where the cool damp air is going to come from?
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2329. DFWjc
Quoting Sfloridacat5:


Texas needs to get a system soon. Once the stronger fronts start coming down, Texas becomes protected from Tropical Systems.


or in the case of Don, as soon as it hit land, it evaporated....
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From the Miami NWS Discussion:

EXTENDED PERIOD...THURSDAY THROUGH SUNDAY...A BIT OF UNCERTAINTY
EXISTS. A STALLED FRONTAL BOUNDARY BETWEEN THE SURFACE REMNANTS OF
LEE AND APPROACHING HURRICANE KATIA BEGINS TO MOVE SOUTHWARD DUE TO
WIND CIRCULATION ABOUT THE 2 SYSTEMS AND WILL POSSIBLY MOVE INTO
N/CENTRAL FLA. THIS SHOVES THE DEEPER MOISTURE SOUTHWARD OVER S FLA
AS WELL. BUT THE POTENTIAL LOW DEVELOPING IN THE SW GULF OF MEX
MAY PULL DRIER AIR NORTHWARD AGAIN OVER S FLA FOR NEXT WEEKEND. A
LOT NEEDS TO HAPPEN TO PULL OFF A WETTER THURSDAY AND FRIDAY AND A
DRIER WEEKEND SCENARIO. SO...WILL GO WITH CLIMO AT THIS TIME BUT
EXPECT AFTERNOON/EARLY EVENING SHOWERS AND THUNDERSTORMS.
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pressure is at 995 with ten inches of rain
Member Since: June 17, 2011 Posts: 11 Comments: 6439
Watch this area, VERY closely. The GFS & ECMWF both develop this into a tropical cyclone. Also, 95L has good model support but not until for a while. Meaning, don't expect the chances to go up for it anytime soon.
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2325. scott39
Quoting P451:


She is in bone dry conditions with wind shear.

Never seen a Cat 4 or Cat 5 in bone dry conditions with wind shear.

Storms of that strength require both moisture and a low shear environment.
Whats your thoughts in regards to strength and track of 95L. Will the Bermuda high be strong enough for a Southern route or do you expect a recurve away from the Conus?
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2324. ackee
Quoting Pirate999:


Agreed.. what is interesting to me is that ECMWF doesn't have anything developing in Campeche but along with GFS it has a storm developing mid-Caribbean toward the end of the model runs. CV storms can be fearsome but I'm more worried about Caribbean and GOM developed storms. Very warm water and more likelihood of a land strike.
agree the first system the ECMWF devlops is 95L think this will track throght the carrb affect the gulf notice the model devlop the system in the carrb to me very early but think this is the most likely track given HIGH will be stronger and system is well south too
Member Since: July 15, 2008 Posts: 0 Comments: 1341
2323. HCW
Quoting scott39:
The developement is not very impressive on model runs yet. I dont remember TCs forming like this in the GOM so early in the season. This usually happens in late Sep and October/Nov.

Or in May and June
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Quoting DFWjc:


And look at that dry air coming back in from the north, Texas just can't win right now....


Texas needs to get a system soon. Once the stronger fronts start coming down, Texas becomes protected from Tropical Systems.
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our season is kinda like 08 very INACTIVE CAPE VERDE SEASON 2008 only had bertha and ike as the cape verdes. we only have katia and ?? probably 1 more
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2320. scott39
Quoting Jedkins01:




000
FXUS62 KTBW 051216
AFDTBW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
816 AM EDT MON SEP 5 2011




GUIDANCE KEEP THE MID LVL TROUGH MEANDERING OVER THE CENTRAL
PORTIONS OF THE NATION THROUGH THE WEEKEND...WITH GFS AND DGEX
LEANING TOWARDS DEVELOPING A SFC LOW OVER THE SOUTHERN GULF AND
TRACKING IT INTO THE AREA BY SUNDAY. IT IS STILL TOO EARLY TO
EMBRACE THIS SOLUTION...ALTHOUGH NOW HAVING TWO MODELS SUGGESTING A
LOW FORMATION CALLS FOR PAYING EXTRA ATTENTION TO UPCOMING MODEL
RUNS. THEREFORE...CONFIDENCE REMAINS LOW FOR NEXT WEEKEND`S
FORECAST. FOR NOW...WILL USE GFS AS BASE FOR WINDS BUT CAPPING
SPEEDS TO AROUND 10 KNOTS AND BRINGING BACK ONSHORE FLOW FROM
THURSDAY THROUGH SATURDAY EACH AFTERNOON.


The NWS here is talking about it too.
The developement is not very impressive on model runs yet. I dont remember TCs forming like this in the GOM so early in the season. This usually happens in late Sep and October/Nov.
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USGS 07381349 Caillou Lake (Sister Lake) SW of Dulac, LA





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Quoting ackee:
similar to how the GFS has been developing a lot of system just a hint that tropics is about to get even more active again


Agreed.. what is interesting to me is that ECMWF doesn't have anything developing in Campeche but along with GFS it has a storm developing mid-Caribbean toward the end of the model runs. CV storms can be fearsome but I'm more worried about Caribbean and GOM developed storms. Very warm water and more likelihood of a land strike.
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2314. HCW
Quoting scott39:
I just heard on the local news here in Mobile that winds could gust up to 60mph at times.


Yes it's a severe Thunderstorm warning and the critera for those are winds 60mph and above. The threat has ended for you as of 10 minutes ago
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2313. DFWjc
Quoting Neapolitan:

I know it's a cliche at this point, but Texas just can't get a break; every piece of good news is offset by equal--or worse--bad news.

Good news: TS Lee forms in the Gulf.

Bad news: Lee misses the state entirely.

Good news: a cold front yesterday broke the months-long heat wave (for example, yesterday was the first since May 27 that Wichita Falls failed to reach 90 degrees).

Bad news: the front, combined with the winds on Lee's left side, brought strong and drying winds that fanned deadly and destructive fires.

Good news: temps across the state are downright chilly; many Panhandle towns are in the mid 40s this morning.

Bad news: 100-degree temps are expected to return by next week to many areas.

Good news: fall and then winter are coming, so the hot and dry weather will eventually be gone for many months.

Bad news: Texas' State climatologist says 2012 may be just as dry--if not drier.


And look at that dry air coming back in from the north, Texas just can't win right now....
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The drought in Texas (and elsewhere) is terrifying. I think I'm amazed that in this day and age, with all of our advances in the sciences, we can't do something to "make it rain" where it's needed.
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2311. jpsb
Quoting Pirate999:


Don't hold your breath on that one.. Northers will give us some rain late in the year and during winter but not much else.
yeah I would need a good soaking rain within the next 10 days to be able to plant the garden. My garden is a good sized one and we are under water restrictions so I don't want to use MUD water to keep it alive. Seedlings really need a moist environment to get going. I'm going to be watching carefully for any chance of rain still hoping to get in a fall garden. I have until sept 15 to plant.
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Latest models have the remains of Lee curving back into the mid-west or Ohio valley, rather than a traditional recurve. Will that affect what happens to Katia in the Atlantic?
Link
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The ignore feature is obsolete when the member I am trying to ignore is constantly being quoted. >:(
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Quoting Sfloridacat5:
Cantore just hinted to a GOM system forming.

He said something like "Fronts and the GOM don't get along so well this time of year." "A hint of things to come."




000
FXUS62 KTBW 051216
AFDTBW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
816 AM EDT MON SEP 5 2011




GUIDANCE KEEP THE MID LVL TROUGH MEANDERING OVER THE CENTRAL
PORTIONS OF THE NATION THROUGH THE WEEKEND...WITH GFS AND DGEX
LEANING TOWARDS DEVELOPING A SFC LOW OVER THE SOUTHERN GULF AND
TRACKING IT INTO THE AREA BY SUNDAY. IT IS STILL TOO EARLY TO
EMBRACE THIS SOLUTION...ALTHOUGH NOW HAVING TWO MODELS SUGGESTING A
LOW FORMATION CALLS FOR PAYING EXTRA ATTENTION TO UPCOMING MODEL
RUNS. THEREFORE...CONFIDENCE REMAINS LOW FOR NEXT WEEKEND`S
FORECAST. FOR NOW...WILL USE GFS AS BASE FOR WINDS BUT CAPPING
SPEEDS TO AROUND 10 KNOTS AND BRINGING BACK ONSHORE FLOW FROM
THURSDAY THROUGH SATURDAY EACH AFTERNOON.


The NWS here is talking about it too.
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Sorry, newscasters
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2306. ackee
Quoting Gearsts:
ECMWF showing 4 systems and a possible last Cape Verde system coming off africaLink
similar to how the GFS has been devloping a lot of system just a hint that tropics is about to get even more active again
Member Since: July 15, 2008 Posts: 0 Comments: 1341
Katia we hardly knew you, Good-bye! All the mets and newcasters had difficulty pronouncing your name.LOL!
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2304. Gearsts
ECMWF showing 4 systems and a possible last Cape Verde system coming off africaLink
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Quoting P451:


Agreed.



Katia have always been in an extremely dry environment and with shear. Just impressive how she's been able to survive within it. She's always struggled with it...and if she had been in a moist environment there is little doubt she could have become a Cat 4 if not Cat 5 storm.

There is just something about her structure that comes along once in a while. An "ordinary" storm would have succumbed to the dry air likely remaining a rather modest TS.

Somehow, someway, she has done a solid job at remaining strong in the face of an environment that does most cyclones in.


There has been plenty of category 4 or 5 hurricanes surrounded by dry air in the Atlantic. It is not a problem for well developed hurricanes if they have a strong anti-cyclone overhead, which protects the inner core, and thus the entire cyclone.
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Quoting Pirate999:
To pass the time.. how about this model on the 20th of September.. 2 storm and one developing in the lower Caribbean.. did I read that right?



Ok.. a link instead..LOL..

Link
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2301. CaneBob
High pressure systems seemingly will keep Invest 95 on a more Southerly path should it develop. I fear we are going to have an active September and October.
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Quoting scott39:
Goodmorning, Gust up to 40mph and heavy rain here in NW Mobile county this morning. Im glad Lee is a baby, when it comes to wind.


Lee has turned into a strong southerly fetch of wind (out ahead of the cold front) covering the Eastern part of the GOM. High surf advisories with strong south winds along the entire west coast of Florida.
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sorry but the drought in the southern states wont really get any better once again we are going to get a STRONG la nina AGAIN. which means two things. MORE DROUGHT, and 2 if a new la nina forms and maintains itself or just becomes enso neutral again, ANOTHER ACTIVE HURRICANE SEASON...;
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2298. scott39
I just heard on the local news here in Mobile that winds could gust up to 60mph at times.
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To pass the time.. how about this model on the 20th of September.. 2 storm and one developing in the lower Caribbean.. did I read that right?

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Wind kicking butt in Ft. Morgan,AL this AM. TS conditions. About to get hit by rain band.
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Cantore just hinted to a GOM system forming.

He said something like "Fronts and the GOM don't get along so well this time of year." "A hint of things to come."
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Quoting jpsb:
Trying to decide is I should plant a fall garden this year. Any chance of se Texas getting any rain this fall? tia


Don't hold your breath on that one.. Northers will give us some rain late in the year and during winter but not much else.
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2293. scott39
Goodmorning, Gust up to 40mph and heavy rain here in NW Mobile county this morning. Im glad Lee is a baby, when it comes to wind.
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2292. jpsb
Quoting Neapolitan:


Bad news: Texas' State climatologist says 2012 may be just as dry--if not drier.
Trying to decide if I should plant a fall garden this year. Any chance of se Texas getting any rain this fall? tia
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Quoting Fishaholic25fl:
So that burst of convection in central gulf is suppost to develop. anyone have any models for that?



some models yesterday predicated a storm in the BOC forming on Friday and moving to the North
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Quoting Fishaholic25fl:
So that burst of convection in central gulf is suppost to develop. anyone have any models for that?


That back side tail of Lee is not what the models have developing in the Bay of Campeche...
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About JeffMasters

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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