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Tropical Storm Lee lingers off Louisiana coast

By: Dr. Jeff Masters, 1:16 AM GMT on September 04, 2011

Tropical Storm Lee continues to bring heavy rain, moderately strong wind gusts, and tornado risk to the Gulf Coast states east of Texas. Lee is 55 miles south of Lafayette, Louisiana, and is drifting almost due north at 4 mph. Lee's central pressure dropped to 988 mb since this morning, but has maximum sustained wind speeds that have decreased to 50mph. The National Hurricane Center has extended the tropical storm warning eastward to Destin, Florida. Since this morning, New Orleans Lakefront Airport has received about another inch of rain for a storm total of 6.87 inches. Rainfall estimates from radar suggest some locations, especially close to the coast, might have already seen up to 8 inches of rain from Tropical Storm Lee. Although the New Orleans area is in a dry slot of the storm, more rain can be expected through the night in the form of isolated storms with heavy downpours. Louisiana's Jefferson Parish officials ordered a mandatory evacuation for three towns earlier today: Lafitte, Crown Point, and Barataria. Heavy rain and tidal surge pushed the water of Bayou Barataria into the surrounding low-lying areas, and officials warned that if residents didn't leave, they might become stranded for a couple of days.


Figure 1. Infrared satellite of Tropical Storm Lee captured around 6pm EDT. Source: NOAA.

Forecast for Tropical Storm Lee
Lee's forecast hasn't changed much since this morning. Dry air is being pulled in from the west, which is giving the storm a very subtropical appearance, and is mitigating intensification. Earlier today, two centers of circulation were visible in satellite and confirmed by Hurricane Hunters. The centers were rotating around each other in full Fujiwara fashion, and although they were scientifically interesting, it meant that there was no clear center of circulation, and probably helped to weaken storm. The National Hurricane Center expects that Lee will come ashore in Louisiana later this evening and linger over the region until Monday, when it will finally be pushed north by a mid-latitude wave.

Lee's tornado threat
A tornado watch is in effect for southern Louisiana and portions of Mississippi, Alabama, and the western Florida Panhandle until 10pm CDT. The forecast is for small and short-lived tornadoes, but the threat for tornado damage is still there. A PhD student at Georgia Tech (and my former group member), James Belanger, runs a skillful model to predict the number of tornadoes that a tropical cyclone could produce. The model uses variables such as the size of the storm, the maximum wind speed, and moisture. For the 2008 hurricane season, the model accurately predicted the number of tornadoes that would be spawned from a quite a few tropical cyclones, including Hurricane Dolly, Tropical Storm Edouard, Tropical Storm Fay, and Hurricane Ike. Given today's forecast track and intensity, Belanger's model is forecasting 30-40 tornadoes could be spawned from Tropical Storm Lee, mainly in the Southeast states east of and including Louisiana.

Interestingly, although the nose of dry air that's being pulled in from drought-stricken Texas (visible in the satellite image above) is acting to keep the storm weak, it's also playing a role in the number of tornadoes that could be spawned from Lee. The dry air is a crucial component for the storm to develop discrete, isolated thunderstorm cells (versus a large shield of heavy rain). The discrete cells, just like during severe weather season, are the storms that are most capable of producing a tornado.

Angela

Hurricane

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

A plea to those who post model run snapshots -- my old eyes can't tell from those tiny images what model it is, what date it was run, what hour it was initialized or what hour in the run is portrayed. The majority of the time, the image is not even linked to a larger version. I am fairly sure I am not alone in this thought.

At a minimum, something as simple as GFS,0Z, 72hrs in text before or after the image would go a long, long way in making such posts relevant. I am hoping posters will be willing to take the extra half second to add the info so that their point is not lost due to a lack of graphics readability. I want to understand why you even thought it was important to post it and can't without knowing what it is you are posting.
1504. ncstorm
DESPITE THE QUICK STRENGTHENING OVER THE PAST 6 TO 12 HOURS...ADT
ESTIMATES HAVE LEVELED OFF AT 85 KT...AND IT IS HARD TO TELL IF THE
CYCLE OF RAPID INTENSIFICATION IS GOING TO CONTINUE DURING THE DAY.
THE SHIPS MODEL IS STILL DIAGNOSING ABOUT 15 KT OF SOUTH TO
SOUTHWESTERLY VERTICAL SHEAR OVER KATIA...BUT THE HURRICANE MAY BE
BENEFITING FROM UPPER-LEVEL DIVERGENCE ASSOCIATED WITH OUTFLOW
JETS TO ITS NORTH AND NORTHEAST. THE OFFICIAL INTENSITY FORECAST
IS AT THE HIGHER RANGE OF THE INTENSITY GUIDANCE...FOLLOWING CLOSE
TO THE GFDL AND HWRF MODELS. HOWEVER...THE ENVIRONMENT APPEARS
SUFFICIENTLY CONDUCIVE FOR INTENSIFICATION...AND KATIA COULD STILL STRENGTHEN MORE THAN INDICATED HERE.

FORECAST POSITIONS AND MAX WINDS

INIT 04/1500Z 21.9N 59.2W 85 KT 100 MPH
12H 05/0000Z 22.9N 60.6W 95 KT 110 MPH
24H 05/1200Z 24.1N 62.4W 100 KT 115 MPH
36H 06/0000Z 25.2N 64.0W 100 KT 115 MPH
48H 06/1200Z 26.2N 65.6W 105 KT 120 MPH
72H 07/1200Z 28.0N 68.5W 105 KT 120 MPH
96H 08/1200Z 30.0N 71.5W 105 KT 120 MPH
120H 09/1200Z 33.0N 72.0W 95 KT 110 MPH
1506. ncstorm
1507. P451
Quoting canehater1:
If someone already posted this I apologize..it is from this mornings NWS New Orleans forecast discussion
and explains what the NAM was thinking...






Very good read, thanks. It makes sense.
000
NOUS42 KNHC 041500
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1100 AM EDT SUN 04 SEPTEMBER 2011
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 05/1100Z TO 06/1100Z SEPTEMBER 2011
TCPOD NUMBER.....11-096

I. ATLANTIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.
3. REMARK: POSSIBLE NOAA G-IV RESEARCH MISSION
FOR HURRICANE KATIA TAKING OFF 06/1100Z.
Quoting CybrTeddy:
Not bad Katia.
Nice job, Katia! You made an eye for yourself quicker then Irene. P.S. Anybody have a microwave image of Katia?
Quoting P451:


It's not a matter of liking something or not.

It's an observation that usually when you have a hurricane whose pressure drops significantly you would expect a color enhanced IR image to show a more solid and broad region of -70C into the -80Cs range.

For reasons unknown, Katia remains broad in the -60s, with some -70Cs.

Her visible presentation reflects a deepening storm. Yet she doesn't appear to have the truly deep convection you would expect to find.

While that may come, and should come, it is curious that it is not there.


Interestingly, a lot of the same can be said for Irene.
Big BOOM -- there went the power.
The models shifted right as expected,they flip-flop again!
1513. beell
A little bit of a veer to the winds in the first 5,000 ft. And some SW flow on top.

Tallahassee VAD



Quoting overwash12:
The models shifted right as expected,they flip-flop again!
please, do tell, which ones shifted right ?
How long can Florida keep getting luck?



Wow!.I see Katia had done some RI while I was sleep.
Quoting Beachfoxx:
Big BOOM -- there went the power.


ok, i have had enough excitement for today.
Quoting hunkerdown:
please, do tell, which ones shifted right ?
All,except UKMET.
1519. aimetti
Nm graphic changed?
Tornado in bay according to NWS. going to be long day... Power back on.
Quoting sugarsand:


ok, i have had enough excitement for today.
1521. ncstorm
Quoting overwash12:
All,except UKMET.


Euro and HWRF shifted west
1522. 7544
Quoting scooster67:
How long can Florida keep getting luck?





hmmm Link
As the season moves on, Florida's chances for a Tropical System should increase.

More storms should start forming in the Caribbean and GOM with movement towards the middle Gulf Coast and Florida.

Texas will become less of a player along with the mid Atlantic and N.E.But there's still a while to for them though.
I predict that Katia should peak out as a 125-135mph major hurricane. Maybe more if she continues to rapidly intensify.
Quoting ncstorm:


Euro and HWRF shifted west
I hope they're wrong! N.C. would suffer on the OBX,they are still cleaning up after Irene!
Quoting Beachfoxx:
Tornado in bay according to NWS. going to be long day... Power back on.
Stay safe.
1527. JGreco
Quoting gbreezegirl:
Stay safe.



Where Choctawhatchee Bay....I live near the bay..is there ant specifics??
Quoting ncstorm:


Euro and HWRF shifted west



how far W
Quoting Tazmanian:



how far W


west
1531. JGreco
Quoting JGreco:



Where Choctawhatchee Bay....I live near the bay..is there ant specifics??


Going towards the North part of the bay..still scary though:0
Pensacola here, was keeping an eye out for strange bug/animal behavior only thing i really noticed the last few days was an increase in spiders webbing the outside of my house...kinda creepy
I'm happy...
normally I say that I am happy when storms to the east of me cross 22 North

today 21.9 is enough to make me happy.
Quoting Tazmanian:



how far W
euro shows katia scraping or making landfall in eastern NC then make a sharp east north east turn
Quoting TropicalAnalystwx13:


west



but how far is W too the USA ???
I think katia may have an eye starting to peep out.
Quoting P451:


It's not a matter of liking something or not.

It's an observation that usually when you have a hurricane whose pressure drops significantly you would expect a color enhanced IR image to show a more solid and broad region of -70C into the -80Cs range.

For reasons unknown, Katia remains broad in the -60s, with some -70Cs.

Her visible presentation reflects a deepening storm. Yet she doesn't appear to have the truly deep convection you would expect to find.

While that may come, and should come, it is curious that it is not there.


Always been and always will be reasons unknown with these storms.
:)

Taz's wisdom in saying "like it or not," I think was meant to convey this simple fact - Tropical cyclones are what they are. They often do the unexpected, and no amount of head-scratching or second-guessing will change that.
:)
Quoting wunderweatherman123:
euro shows katia scraping or making landfall in eastern NC then make a sharp east north east turn



and what about the other mode run
Beautiful...

WTF:
1540. ackee
poll time where will katia go ?

A NC
B out to sea
C NEW YORK
D CLOSE BRUSH UP THE EAST COAST
E fl
F NEW ENGLAND
G canada

which model do u trust the most will KATIA track ?

A GFS
B ECMWF
C CMC
D NOGAPS
e ukmet
F GFDL
G HWRF
1541. ncstorm
Quoting Tazmanian:



and what about the other mode run


HWRF only goes out to 126 hours..

Villa Tasso - mirimar Beach. Going north across bay.
Quoting JGreco:



Where Choctawhatchee Bay....I live near the bay..is there ant specifics??
Quoting ackee:
poll time where will katia go ?

A NC
B out to sea
C NEW YORK
D CLOSE BRUSH UP THE EAST COAST
E fl
F NEW ENGLAND
G canada

which model do u trust the most will KATIA track ?

A GFS
B ECMWF
C CMC
D NOGAPS
e ukmet
F GFDL
G HWRF



i pick C
Quoting ncstorm:


HWRF only goes out to 126 hours..





ok thanks
Quoting Beachfoxx:
Tornado in bay according to NWS. going to be long day... Power back on.


Good Morning BeachFox,
You all becareful.... I chased those types of tornados yesterday from Mobile to Pass Christian MS.... Although I did see 1 water spout in MS Sound. But by the time I got my camera out it was gone....

Taco :o)
Interesting… we had turtles in fron yard & frogs. Live on bay, normally see them on the bayside of house.
Quoting Jebekarue:
Pensacola here, was keeping an eye out for strange bug/animal behavior only thing i really noticed the last few days was an increase in spiders webbing the outside of my house...kinda creepy
1547. BDADUDE
Quoting Beachfoxx:
Villa Tasso - mirimar Beach. Going north across bay.

Wouldnt that be a
waterspout?
1549. Seastep
Quoting CaicosRetiredSailor:
I'm happy...
normally I say that I am happy when storms to the east of me cross 22 North

today 21.9 is enough to make me happy.


LOL. 25 is my number, even though there is the occasional Ike.
Quoting hurricanehunter27:
I think katia may have an eye starting to peep out.

Possibly. Could just be a dry spot.

*Sarcasm flag on*
1551. Seastep
The H to Katia's N has strengthened. Hope it doesn't build W too much as the ULL moves out.

Quoting scooster67:
How long can Florida keep getting luck?



Not if this run verifies, just look at the gap between the CONUS High and the Bermuda High, of course anything past 5 days is too far out for me :)
Quoting Ameister12:

Possibly. Could just be a dry spot.

*Sarcasm flag on*



no trust me thats a eye starting too pop out
Hey Taco -

Watching radar, will head downstairs if it gets bad. Lull of storm right now.

Quoting taco2me61:


Good Morning BeachFox,
You all becareful.... I chased those types of tornados yesterday from Mobile to Pass Christian MS.... Although I did see 1 water spout in MS Sound. But by the time I got my camera out it was gone....

Taco :o)
Quoting ackee:
poll time where will katia go ?

A NC
B out to sea
C NEW YORK
D CLOSE BRUSH UP THE EAST COAST
E fl
F NEW ENGLAND
G canada

which model do u trust the most will KATIA track ?

A GFS
B ECMWF
C CMC
D NOGAPS
e ukmet
F GFDL
G HWRF
D,G;B
Quoting Tazmanian:



no trust me thats a eye starting too pop out


Yeah, I know it's an eye.
1540 ackee "poll time: where will katia go?"

Texas :-) I'm Texcasting everything until after the TropicalCyclone proves that it's going elsewhere through a sustained increase in distance away from Texas... or the Drought breaks, whichever comes first
Click to see the 4Sept_12pmGMT mapping for TS.Lee
- - - - - - - - - - - - - - - - - - - - - - - - - -
6amGMT's TS.Lee has been reevaluated&altered to Hurricane status for H.Katia's_12pmGMT_ATCF
20.9n57.8w has also been re-evaluated&altered
21.1n58.0w, 21.6n58.8w are now the most recent positions
Starting 3Sept_12pmGMT and ending 4Sept_12pmGMT

The 4 eastern line-segments represent HurricaneKatia's path
and the westernmost line-segment is the straightline projection.

Using straightline projection of the travel-speed&heading derived from the
ATCF coordinates spanning the 6hours between 6amGMT then 12pmGMT :
H.Katia's travel-speed was 10.3mph(16.6k/h) on a heading of 303.9degrees*(NW)
H.Katia was headed toward passage over Beaufort,SouthCarolina ~6days from now

Copy&paste 19.4n55.5w, 19.4n55.5w-19.9n56.2w, 19.9n56.2w-20.4n57.0w, 20.4n57.0w-21.1n58.0w, 21.1n58.0w-21.6n58.8w, bft, 21.1n58.0w-32.322n80.454w into the GreatCircleMapper for more info

The previous mapping (for 4Sept_6amGMT)

* 303.75degrees is midway between WNW and NW
I suppose while over bay it would be. Radar indicates another t'nado on so. Walton co.
Quoting BDADUDE:

Wouldnt that be a
waterspout?
1561. ncstorm
5am Wind advisory from the NHC
CAPE HATTERAS 34 X X( X) X( X) X( X) X( X) 2( 2) 11(13)
CAPE HATTERAS 50 X X( X) X( X) X( X) X( X) X( X) 3( 3)
CAPE HATTERAS 64 X X( X) X( X) X( X) X( X) X( X) 1( 1)

MOREHEAD CITY 34 X X( X) X( X) X( X) X( X) 1( 1) 11(12)
MOREHEAD CITY 50 X X( X) X( X) X( X) X( X) X( X) 3( 3)

WILMINGTON NC 34 X X( X) X( X) X( X) X( X) 1( 1) 8( 9)

11Am Wind Advisory
CAPE HATTERAS 34 X X( X) X( X) X( X) X( X) 3( 3) 17(20)
CAPE HATTERAS 50 X X( X) X( X) X( X) X( X) X( X) 5( 5)
CAPE HATTERAS 64 X X( X) X( X) X( X) X( X) X( X) 1( 1)

MOREHEAD CITY 34 X X( X) X( X) X( X) X( X) 2( 2) 14(16)
MOREHEAD CITY 50 X X( X) X( X) X( X) X( X) X( X) 5( 5)
MOREHEAD CITY 64 X X( X) X( X) X( X) X( X) X( X) 2( 2)

WILMINGTON NC 34 X X( X) X( X) X( X) X( X) 1( 1) 12(13)
WILMINGTON NC 50 X X( X) X( X) X( X) X( X) X( X) 4( 4)
WILMINGTON NC 64 X X( X) X( X) X( X) X( X) X( X) 1( 1)
1562. scott39
SW and NW Mobile County where I live had some close calls with tornados last night. We were under a tornado warning from about 11:45pm until 1:15am. The local news interrupted the TV show and gave me a lesson on what "hook" like possible tornados look like. At one time I counted 5 seperate ones down in the GOM just W of Dauphin Island going N into Mobile. Thankfully most lost thier "hook" like signature once over land. One strong cell went over my house, but at that time looked not to be a tornado in the making. It was still strong with winds and rain..................Can we expect more rain bands from Lee as it moves in our direction?
1563. ncstorm
Quoting TropicalAnalystwx13:




wwwwhhhaaatttt??
1564. Seastep
NEW BLOG
Yes.
Quoting scott39:
SW and NW Mobile County where I live had some close calls with tornados last night. We were under a tornado warning from about 11:45pm until 1:15am. The local news interrupted the TV show and gave me a lesson on what "hook" like possible tornados look like. At one time I counted 5 seperate ones down in the GOM just W of Dauphin Island going N into Mobile. Thankfully most lost thier "hook" like signature once over land. One strong cell went over my house, but at that time looked not to be a tornado in the making. It was still strong with winds and rain..................Can we expect more rain bands from Lee as it moves in our direction?
1566. ackee
Quoting aspectre:
1540 ackee "poll time: where will katia go?"

Texas. I'm Texcasting everything until the storm proves that it's going elsewhere through sustained movement away from Texas... or the Drought breaks, whichever comes first
well if GFS is right seem like storm that tracks into the carrb and then GULF hopeful texas will get some rain from it
katia may get bumped up to mid cat 3 or cat 4 depeding on how cold the tops will be in the eye wall.
Quoting TropicalAnalystwx13:


Well I think this is how we all envisioned Katia would look like, a classic Cape Verde Storm :)
Oh NO!...my lull ended too quick. lol
New blog is up.....
Quoting scott39:
SW and NW Mobile County where I live had some close calls with tornados last night. We were under a tornado warning from about 11:45pm until 1:15am. The local news interrupted the TV show and gave me a lesson on what "hook" like possible tornados look like. At one time I counted 5 seperate ones down in the GOM just W of Dauphin Island going N into Mobile. Thankfully most lost thier "hook" like signature once over land. One strong cell went over my house, but at that time looked not to be a tornado in the making. It was still strong with winds and rain..................Can we expect more rain bands from Lee as it moves in our direction?


I'm thinking we will have a lot more of those to come... As "Lee" gets closewr to us here in Mobile the Tor-Con will be going up.... Its Pouring right now and would not surprise me to have a warning coming soon ....

Taco :o)
Quoting Ameister12:


Katia, the perfect example of ... a FISH. I knew it would be so since the begining... but I was told it was too early to be too confident. Katia won't affect any land mass, so NEXT please!
Quoting overwash12:
The models shifted right as expected,they flip-flop again!


Once again, Katia is only marine concern.
Quoting NavarreMark:
The cover for my gas grill disappeared during the night. Lost more pears from the tree. The DOOM is thick this morning. STAY SAFE


Friend of mine lives in Navarre. She got home from work at 2am and said there was a tornado in Navarre during early morning hrs.
Quoting primez:
Long time lurker here. Just stopped by to post that I have this gut feeling that Katia is going to develop into an annular hurricane similar to Isabel. Any thoughts?
Not seeing much out there to support this right now...

Quoting P451:


I'm glad you brought up the NHC. Through all the model runs they were a steady hand. They put up their cone heading for the LA coast and they stuck with it. No fancy curves or loops or anything. Just straight in. Lee followed it.

For Katia, especially after seeing how Lee has behaved, I would be inclined to agree that Katia will slide between NC and Bermuda and up and out.

It would even appear that it will continue curving and not affect the Canadian Maritimes either.

It's still a little early to be certain and disregard the system but it appears that this will occur.

A timely reminder IMO that it's not enough to look at the models, which represent mere possibilities. There must be some skill in analysis of data, real time imagery and the varied model output in order to develop a reasonable forecast. IMO this is why NHC forecasts generally, though not always, outperform individual and even ensemble models.
Quoting Tazmanian:



no trust me thats a eye starting too pop out


Starting is the right word here.. We've gone from Uniform Central Dense Overcast scene to an EMBEDDED CENTER~ Arc of convection within central overcast cloud region.. know your scene types.. now with pictures.. Start around page 27..but I expect the regulars to have already read the whole thing;)

AOI in the CATL has good turning...
GFDL & HWRF has been going okay by the numbers with Katia..you can even see the eye wall replacement cycles they have planned for Katia. & statistically we're at out upper limits for another annular type storm globally this year.. they're rare.
Link

TWAVE AT 40W COULD BE THE NEXT INVEST. HOPEFULLY THE NE ISLANDS WILL GET SOME DECENT RAIN FROM IT.
1581. HCW
Radar is back on after an 8 hour power outage

Hopefully the 40W AOI won't go NORTH!! Please go west and give us rain. Even if it becomes a TS before us, this still fine! Tropical Storm aren't bad for our tiny islands, we are not as vulnerable as hispaniola. Irene was a 50-60kts TS when she passed through, and she didn't do much at all (60MPH gusts and only 2.5 inches of rain)!
So let's see how this evolves next few days
Had to compare model preformace on Lee..especially where the GFNI stood..


Model error for Lee in nm.
Model Name 0hr 24hr 48hr 72hr
GFNI 0 70.5 75.4 -
GFDI 0 62.5 63.3 63.6
GFDL 18.0 42.9 62.7 77.9
GFDN 7.9 52.1 55.8 -
CMC 24.3 56.8 73.9 108.4
EGRR 24.7 52.6 90.8 -
AVNO 28.2 43.3 51.4 48.6
BAMD - 65.8 73.5 84.8
BAMM - 59.5 97.4 155.6
BAMS - 81.0 154.5 248.4
AEMN 26.9 61.2 97.8 118.2
HWRF 21.4 70.3 85.1 138.3
LBAR 0 66.2 97.3 85.5
LGEM 0 58.7 62.8 126.0
NAM 28.0 71.0 41.8 48.5

So I wake up this morning to see Katia almost a cat 3, and the cone shifted west?! who was left in charge?!
Quoting GTcooliebai:
Not if this run verifies, just look at the gap between the CONUS High and the Bermuda High, of course anything past 5 days is too far out for me :)
what do u mean if this run verifies what would happen to florida we have been very lucky