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WTNT41 KNHC 061453
TCDAT1
TROPICAL DEPRESSION IDA DISCUSSION NUMBER 9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL112009
1000 AM EST FRI NOV 06 2009
SATELLITE IMAGES INDICATE THAT BANDS OF THUNDERSTORMS CONTINUE TO
FORM IN THE NORTHERN SEMICIRCLE OF IDA...THOUGH SOMEWHAT REMOVED
FROM THE CENTER. NOAA BUOY 42057 SHOWED PEAK 1-MINUTE WINDS OF 29
KT EARLIER THIS MORNING...SO THE INITIAL INTENSITY WILL BE HELD AT
30 KT. IDA WILL HAVE AN OPPORTUNITY FOR SOME RESTRENGTHENING
OVERNIGHT AFTER IT EMERGES FROM EASTERN HONDURAS. THERE CONTINUES
TO BE A LARGE DISAGREEMENT AMONG THE MODELS ON HOW MUCH
INTENSIFICATION TO EXPECT WITH IDA. THE STATISTICAL GUIDANCE
GENERALLY SHOWS A RATHER MODEST AMOUNT OF RESTRENGTHENING...WHILE
THE REGIONAL HURRICANE MODELS SUGGEST THAT IDA WILL BECOME A
HURRICANE AGAIN. SINCE SHEAR IS FORECAST TO BE NEAR 20 KT OVER THE
NORTHWESTERN CARIBBEAN BY MOST OF THE GLOBAL MODELS...AND EVEN
HIGHER IN THE GULF OF MEXICO...THE NHC FORECAST WILL STAY MUCH
CLOSER TO THE STATISTICAL GUIDANCE. AT THE END OF PERIOD...SOME
WEAKENING IS SHOWN DUE TO SHEAR BECOMING STRONG AND COOLER WATERS
IN THE NORTHERN GULF OF MEXICO...WHICH WILL LIKELY START THE
EXTRATROPICAL TRANSITION OF IDA.
IDA HAS TURNED TOWARD THE NORTH...360/6. A WEAK MID-LEVEL RIDGE OVER
THE CENTRAL CARIBBEAN SEA IS FORECAST TO STEER THE STORM NORTHWARD
FOR THE NEXT DAY OR SO. THEREAFTER... IDA SHOULD TURN TOWARD THE
NORTH-NORTHWEST OR NORTHWEST AS SHORTWAVE RIDGING OVER THE
SOUTHEASTERN UNITED STATES BUILDS. IN THE LONG-RANGE...A TROUGH
OVER THE GULF OF MEXICO COULD FORCE IDA TO TURN TO THE NORTH OR
NORTHEAST. HOWEVER...THE INTERACTION OF IDA WITH THAT TROUGH IS
CAUSING A WIDE VARIETY OF MODEL SOLUTIONS... RANGING FROM A FASTER
CENTRAL GULF OF MEXICO LANDFALL TO IDA REMAINING SEPARATE FROM THE
TROUGH AND STAYING OVER THE CENTRAL GULF WATERS. ALTHOUGH SOME OF
THE MODELS HAVE SHIFTED WESTWARD SINCE THE LAST RUN...CLIMATOLOGY
AND THE FORECAST STRONG UPPER- LEVEL SOUTHWESTERLY WINDS SUGGEST
THE EASTERN SOLUTIONS ARE LIKELY CLOSER TO REALITY. THE NHC
FORECAST REMAINS CLOSE TO THE PREVIOUS ONE...AND ON THE EASTERN
SIDE OF THE GUIDANCE ENVELOPE.
THERE IS STILL A THREAT OF LIFE-THREATENING FLASH FLOODS AND MUD
SLIDES CAUSED BY EXTREMELY HEAVY RAIN OVER PORTIONS OF HONDURAS
TODAY.
FORECAST POSITIONS AND MAX WINDS
INITIAL 06/1500Z 15.0N 84.0W 30 KT
12HR VT 07/0000Z 15.7N 84.1W 30 KT...OVER WATER
24HR VT 07/1200Z 16.8N 84.5W 35 KT
36HR VT 08/0000Z 17.9N 85.1W 40 KT
48HR VT 08/1200Z 19.1N 85.8W 45 KT
72HR VT 09/1200Z 22.5N 87.5W 45 KT
96HR VT 10/1200Z 25.0N 87.5W 45 KT
120HR VT 11/1200Z 27.0N 86.0W 40 KT...EXTRATROPICAL
FORECASTER BLAKE/FRANKLIN
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