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WTNT41 KNHC 010901
TCDAT1
TROPICAL STORM NOEL DISCUSSION NUMBER 19
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL162007
500 AM EDT THU NOV 01 2007
NOEL PRODUCED A MAJOR BURST OF CONVECTION EAST OF THE CENTER EARLIER
THIS MORNING...WITH CLOUD TOP TEMPERATURES NEAR -90C AT TIMES.
HOWEVER...THE BURST HAS ENDED...WITH RADAR DATA FROM MIAMI...
NASSAU...AND CAMAGUEY CURRENTLY SHOWING LITTLE PRECIPITATION NEAR
THE CENTER. MAJOR COMMUNICATIONS PROBLEMS HAVE DISRUPTED THE FLOW
OF DATA FROM THE AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT
MONITORING NOEL. HOWEVER...THE PLANE REPORTED THAT THE CENTRAL
PRESSURE HAD FALLEN TO 992 MB AT 05Z. BASED ON THAT AND SATELLITE
INTENSITY ESTIMATES...THE INITIAL INTENSITY REMAINS 50 KT.
THE INITIAL MOTION IS A SOMEWHAT ERRATIC 000/5. WATER VAPOR IMAGERY
AND MODEL ANALYSES INDICATE THAT A LARGE MID/UPPER-LEVEL TROUGH IS
MOVING INTO THE EASTERN UNITED STATES...WITH THE LOW/MID-LEVEL
RIDGE OVER THE WESTERN ATLANTIC MOVING EASTWARD. THE DYNAMICAL
MODELS NOW AGREE THAT NOEL WILL BE PICKED UP BY THE TROUGH...
MOVING SLOWLY NORTHWARD FOR 12 HR OR SO AND THEN ACCELERATING
NORTHEASTWARD. THE NEW FORECAST TRACK IS AN UPDATE OF THE PREVIOUS
TRACK THROUGH 36 HR...AND THEN IS SOMEWHAT TO THE LEFT OF THE
PREVIOUS TRACK THEREAFTER IN RESPONSE TO A LEFTWARD SHIFT IN THE
MODEL CONSENSUS. IT SHOULD BE NOTED THAT THE MOTION DURING THE
FIRST 12 HR COULD BE ERRATIC DUE TO RE-FORMATION OF THE CENTER
CAUSED BY CONVECTIVE BURSTS.
NOEL HAS AN IMPRESSIVE OUTFLOW PATTERN...ESPECIALLY IN THE
NORTHEASTERN SEMICIRCLE. HOWEVER...RAWINSONDE DATA FROM KEY WEST
AND MIAMI SHOW THAT THE OUTFLOW IS CONFINED TO ABOVE 200 MB...WITH
20-30 KT OF WESTERLY FLOW BETWEEN 200-400 MB UNDERCUTTING THE
OUTFLOW AND CAUSING SHEAR. THE SHEAR IS LIKELY TO INCREASE BY 24
HR...LEAVING ONLY A SMALL WINDOW FOR NOEL TO INTENSIFY AS A
TROPICAL CYCLONE. THE INTENSITY FORECAST CALLS FOR NOEL TO
STRENGTHEN TO 60 KT IN 12 HR IN ANTICIPATION OF ANOTHER CONVECTIVE
BURST SIMILAR TO THE ONE THAT JUST FINISHED. AFTER THAT...
INCREASING SHEAR SHOULD STOP DEVELOPMENT. ALL DYNAMICAL MODELS
FORECAST NOEL TO BECOME A LARGE AND INTENSE EXTRATROPICAL LOW OVER
THE WESTERN ATLANTIC STARING IN 36-48 HR...AND THIS IS REFLECTED IN
BOTH THE INTENSITY AND WIND RADII FORECASTS.
THE AIRCRAFT FOUND A BAND OF TROPICAL STORM-FORCE WINDS ABOUT
100-115 N MI FROM THE CENTER IN THE NORTHWESTERN QUADRANT....WITH
THE AIRCRAFT DATA SUPPORTED BY DOPPLER WINDS FROM THE MIAMI WSR-88D
AND A 37 KT SHIP REPORT AT 06Z. THESE WINDS ARE CLOSE ENOUGH TO
THE FLORIDA COAST THAT ANY DEVIATION TO THE LEFT OF THE FORECAST
TRACK WOULD BRING THEM ON TO THE FLORIDA COAST. THUS...A TROPICAL
STORM WARNING IS BEING ISSUED AT THIS TIME FOR THE IMMEDIATE
COASTAL AREA OF MIAMI-DADE AND BROWARD COUNTIES.
FORECAST POSITIONS AND MAX WINDS
INITIAL 01/0900Z 23.7N 78.5W 50 KT
12HR VT 01/1800Z 25.0N 78.1W 60 KT
24HR VT 02/0600Z 27.2N 76.2W 60 KT
36HR VT 02/1800Z 30.5N 73.4W 55 KT...BECOMING EXTRATROPICAL
48HR VT 03/0600Z 34.8N 70.1W 55 KT...EXTRATROPICAL
72HR VT 04/0600Z 43.5N 63.0W 60 KT...EXTRATROPICAL
96HR VT 05/0600Z 53.0N 52.5W 60 KT...EXTRATROPICAL
120HR VT 06/0600Z 57.5N 42.5W 60 KT...EXTRATROPICAL
FORECASTER BEVEN
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