5pm Jeanne discussion

[Brent]

HURRICANE JEANNE DISCUSSION NUMBER 45
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT FRI SEP 24 2004

SATELLITE IMAGERY...ALONG WITH NOAA AND AIR FORCE RESERVE HURRICANE
HUNTER DATA...INDICATE THE INNER-CORE CONVECTION HAS REDEVELOPED.
WHILE RECON DATA ALSO INDICATES CONCENTRIC EYEWALLS HAVE DEVELOPED
...FLIGHT-LEVEL AND STEPPED FREQUENCY MICROWAVE...OR SFMR...WIND
DATA SUGGEST THAT JEANNE MAY BE STARTING TO SHOW SOME SIGNS OF
STRENGTHENING. THE HIGHEST FLIGHT-LEVEL WIND REPORTED WAS 97 KT AT
5000 FEET AND THE HIGHEST SFMR SURFACE WIND WAS 87 KT. THE INITIAL
INTENSITY REMAINS AT 85 KT...BUT IT COULD BE HIGHER SINCE THE
SURFACE PRESSURE IS NOW 965 MB...WHICH TYPICALLY SUPPORTS ABOUT 96
KT SURFACE WINDS.

THE INITIAL MOTION IS NOW 275/10....BUT THE TREND IN THE LAST TWO
RECON FIX POSITIONS SUGGESTS A MOTION OF POSSIBLY 270/11. THE
LATEST NHC MODEL GUIDANCE HAS CHANGED LITTLE...BUT THERE REMAIN
SOME SUBTLE DIFFERENCES THAT COULD SIGNIFICANTLY AFFECT THE FUTURE
TRACK OF JEANNE. MOST OF THE MODEL GUIDANCE HAS MADE A SLIGHT NORTH
AND EASTWARD SHIFT AGAIN...EXCEPT FOR THE NOGAPS AND GFDN MODELS.
MOST OF THE MODEL GUIDANCE TAKE JEANNE TO ALONG OR JUST EAST OF THE
FLORIDA EAST COAST BEFORE TURNING THE HURRICANE NORTH-NORTHWESTWARD
AND PARALLELING THE COASTLINE. ONLY THE NOGAPS...GFDN...AND ETA
MODELS TAKE JEANNE ACROSS SOUTH FLORIDA AND LAKE OKEECHOBEE. THE
NOGAPS AND GFDN MODELS HAVE BEEN VERY CONSISTENT WITH THIS TYPE OF
TRACK THE PAST 36 HOURS. THIS SCENARIO IS SOMEWHAT DISCONCERTING
BECAUSE THOSE ARE THE ONLY MODELS THAT TAKE THE LARGE HIGH/RIDGE
NEAR THE DELMARVA SOUTHWARD TO THE OUTER BANKS OF NORTH CAROLINA
BEFORE MOVING IT TO A POSITION NEAR BERMUDA IN 36 HOURS. THE OTHER
MODELS QUICKLY WEAKEN THE HIGH AND MOVE IT SOUTHEASTWARD. THE EXACT
LOCATION OF THE CENTER OF THE HIGH/RIDGE OVER THE NEXT 12-36 HOURS
WILL DETERMINE HOW FAR WEST JEANNE WILL MOVE BEFORE IT BEGINS TO
MAKE THE TURN NORTHWARD. SPECIAL 18Z UPPER-AIR DATA INDICATE THE
CENTER THE HIGH HAS NOT WEAKENED AND HAS ACTUALLY PUSHED SOUTHWARD
AND IS NOW LOCATED JUST EAST OF WALLOPS ISLANDS IN THE SOUTHERN
DELMARVA. THIS WOULD SUGGEST...AT LEAST IN THE SHORT TERM...THAT
THE NOGAPS-GFDN-ETA SOLUTION IS HANDLING THE STEERING PATTERN THE
BEST. AS A RESULT...NO SIGNIFICANT CHANGE WAS MADE TO THE PREVIOUS
FORECAST TRACK.

NOAA RECON AIRCRAFT FOUND NEARLY A 5F SST DIFFERENCE BETWEEN THE
EASTERN AND WESTERN EYEWALL...CLEARLY INDCIATING THAT JEANNE HAS
CREATED A LOT OF COLD UPWELLING UNDERNEATH THE HURRICANE.
UNFORTUNATELY...JEANNE IS NOW MOVING FASTER AWAY FROM THOSE
UNFAVORABLE OCEAN CONDITIONS AND TOWARD MUCH WARMER WATER...83-84F
...LOCATED FROM THE NORTHWESTERN BAHAMAS TO THE FLORIDA STRAITS. THE
CURRENT FAVORABLE UPPER-LEVEL ENVIRONMENT IS EXPECTED TO CHANGE
LITTLE FOR THE NEXT 24-30 HOURS. THEREFORE...STEADY INTENSIFICATION
...POSSIBLY TO CATEGORY 3/100 KT...IS FORECAST. THE INTENSITY
FORECAST CLOSELY FOLLOWS THE SHIPS MODEL...WHICH BRINGS JEANNE UP
TO 98 KT AND 99 KT AT 24 AND 36 HOURS....RESPECTIVELY.

FORECASTER STEWART

FORECAST POSITIONS AND MAX WINDS

INITIAL 24/2100Z 26.4N 73.5W 85 KT
12HR VT 25/0600Z 26.5N 75.3W 90 KT
24HR VT 25/1800Z 26.6N 77.9W 95 KT
36HR VT 26/0600Z 27.4N 80.2W 100 KT
48HR VT 26/1800Z 29.0N 81.4W 75 KT...INLAND
72HR VT 27/1800Z 32.5N 81.2W 55 KT...INLAND
96HR VT 28/1800Z 36.0N 75.5W 40 KT...OVER WATER
120HR VT 29/1800Z 41.5N 67.0W 35 KT

[Canelaw99]

"THIS SCENARIO IS SOMEWHAT DISCONCERTING
BECAUSE THOSE ARE THE ONLY MODELS THAT TAKE THE LARGE HIGH/RIDGE
NEAR THE DELMARVA SOUTHWARD TO THE OUTER BANKS OF NORTH CAROLINA
BEFORE MOVING IT TO A POSITION NEAR BERMUDA IN 36 HOURS. THE OTHER
MODELS QUICKLY WEAKEN THE HIGH AND MOVE IT SOUTHEASTWARD. THE EXACT
LOCATION OF THE CENTER OF THE HIGH/RIDGE OVER THE NEXT 12-36 HOURS
WILL DETERMINE HOW FAR WEST JEANNE WILL MOVE BEFORE IT BEGINS TO
MAKE THE TURN NORTHWARD. SPECIAL 18Z UPPER-AIR DATA INDICATE THE
CENTER THE HIGH HAS NOT WEAKENED AND HAS ACTUALLY PUSHED SOUTHWARD
AND IS NOW LOCATED JUST EAST OF WALLOPS ISLANDS IN THE SOUTHERN
DELMARVA. THIS WOULD SUGGEST...AT LEAST IN THE SHORT TERM...THAT
THE NOGAPS-GFDN-ETA SOLUTION IS HANDLING THE STEERING PATTERN THE
BEST."


for us in S. FL, that's for sure

[PurdueWx80]

What a great discussion...tells us all we have to deal with and what we need to see for a certain model to verify. I was a bit unsupportive of Stewart during Ivan, but he is again the top forecaster in my mind. Even if he isn't the best forecaster (not saying he isn't, just if), he is a WONDERFUL communicator and tells the public, weather enthusiasts and other meteorologists what exactly to expect. The pure west motion from the last two recon fixes as well as the faster forward motions suggests a strong and building ridge to the north of the storm. Looks like another crazy wx weekend.

[rocknole]

It sure sounds like they are opening the door for a forecast shift to the south and west in the next 12 hours or so. It will be interesting to see, but I think Derek and the others have had this one pegged.

[JTD]

Very interesting and scary discussion. Thanks for posting, Brent.

And I am again becoming concerned about just how strong Jeanne will be at landfall.

[Brent]

Great, detailed discussion by Stewart.

More bad news for Florida...

FLIGHT-LEVEL AND STEPPED FREQUENCY MICROWAVE...OR SFMR...WIND
DATA SUGGEST THAT JEANNE MAY BE STARTING TO SHOW SOME SIGNS OF
STRENGTHENING. THE HIGHEST FLIGHT-LEVEL WIND REPORTED WAS 97 KT AT
5000 FEET AND THE HIGHEST SFMR SURFACE WIND WAS 87 KT. THE INITIAL
INTENSITY REMAINS AT 85 KT...BUT IT COULD BE HIGHER SINCE THE
SURFACE PRESSURE IS NOW 965 MB...WHICH TYPICALLY SUPPORTS ABOUT 96
KT SURFACE WINDS.

[Agua]

Well, I haven't seen a loop since this morning, but the ridge definitely didn't look to be retreating eastward and, in fact, looked to be *building* west and south. Haven't seen a WV loop since arriving at work today, though.

[nolecaster]

5 degree difference on each sides of the eyewall, that is definitely significant. Pretty sure we'll have a cat 3 pretty soon.

[wjs3]

I know others like different forecasters at the NHC, but I believe that Stacy Stewart writes the best discussions. He does such a great job of explaining the synoptic situation!

[Doc Seminole]

Well, with that discussion and MikeW, Derek and SouthernWx all saying more west I think I'll choose to disregard the mandatory evacuation here for 7:00 a.m. If this holds, I don't think we'll see much more the TS winds if that in the Daytona Beach/Ormond Beach area. We may not even lose power!