Tropical Storm IDA Forecast Discussion

000
WTNT41 KNHC 091454
TCDAT1
TROPICAL STORM IDA DISCUSSION NUMBER  23
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL112009
900 AM CST MON NOV 09 2009

THE LAST RECONNAISSANCE DATA THAT SUPPORTED HURRICANE INTENSITY WERE
OBTAINED AROUND 07Z...AND THE SATELLITE PRESENTATION OF IDA HAS
BEEN STEADILY DETERIORATING DURING THE MORNING.  MOST OF THE DEEP
CONVECTION HAS BEEN SHEARED OFF WELL TO THE NORTHEAST OF THE CENTER
AND WILL BE MOVING ONSHORE SHORTLY...LEAVING ONLY A SMALL AREA OF
CONVECTION NEAR THE CENTER.  A QUIKSCAT PASS AROUND 12Z SHOWED
WINDS OF 50-55 KT IN THE CORE...AND ASSUMING THAT THE INSTRUMENT
DID NOT QUITE RESOLVE THE MAXIMUM WIND SPEED...THE ADVISORY
INTENSITY WILL BE SET TO 60 KT.  ANOTHER AIRCRAFT WILL BE IN THE
CYCLONE AROUND 18Z.

WITH IDA MOVING THROUGH AN ENVIRONMENT OF COOLER WATERS AND
INCREASING SHEAR...CONTINUED WEAKENING IS EXPECTED.  THE GLOBAL
MODELS DO NOT SHOW MUCH IN THE WAY OF BAROCLINIC RE-INTENSIFICATION
PRIOR TO LANDFALL...SO THE HURRICANE WARNINGS AND WATCHES ARE BEING
DISCONTINUED...LEAVING ONLY TROPICAL STORM WARNINGS IN PLACE.  THE
OFFICIAL FORECAST IS STILL ABOVE THE ICON CONSENSUS.   

THE LAST AIRCRAFT CENTER FIX SHOWED THE 700 MB- AND SURFACE CENTERS
DECOUPLING...AND SINCE THEN THE SURFACE CENTER HAS BEEN DIFFICULT
TO LOCATE IN SATELLITE IMAGERY. THE INITIAL MOTION IS ESTIMATED AT
340/15. THE FORECAST PHILOSOPHY IS UNCHANGED. IDA IS EXPECTED TO
MOVE GENERALLY NORTHWARD TODAY AHEAD OF A MID- TO UPPER-LEVEL
TROUGH MOVING EASTWARD ACROSS THE NORTHERN GULF OF MEXICO...AND
THEN TURN EASTWARD AS IT BECOMES EMBEDDED WITHIN THIS MID-LATITUDE
SYSTEM.

THE TRACK OF THE SURFACE CENTER OF IDA IS LOSING SIGNIFICANCE IN
TERMS OF THE EFFECTS OF THIS STORM.  STRONG WINDS COVER A LARGE
AREA OF THE GULF OF MEXICO AND THE ASSOCIATED RAINS ARE MOVING WELL
AHEAD OF THE CENTER.  THIS SHOULD CONTINUE TO BE THE CASE AS IDA
WEAKENS AND BEGINS TO LOSE TROPICAL CHARACTERISTICS. 

FORECAST POSITIONS AND MAX WINDS

INITIAL      09/1500Z 26.5N  88.3W    60 KT
 12HR VT     10/0000Z 28.6N  88.7W    55 KT
 24HR VT     10/1200Z 30.4N  88.2W    50 KT...INLAND
 36HR VT     11/0000Z 31.2N  86.6W    40 KT...EXTRATROPICAL
 48HR VT     11/1200Z 30.5N  84.5W    30 KT...EXTRATROPICAL
 72HR VT     12/1200Z...DISSIPATED

$$
FORECASTER FRANKLIN