323 
 WTNT41 KNHC 100300
 TCDAT1
 TROPICAL STORM IDA DISCUSSION NUMBER  25
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL112009
 900 PM CST MON NOV 09 2009
  
 RADAR AND SATELLITE IMAGES SHOW THE CONVECTION THAT WAS NEAR THE
 CENTER DURING THE AFTERNOON HAS WEAKENED AND SHEARED OFF TOWARD THE
 NORTH.  THIS WAS CONFIRMED BY A RECENT AIRCRAFT FIX THAT POSITIONED
 THE CENTER EAST OF SOUTHEASTERN LOUISIANA WELL SOUTH OF THE
 REMAINING DEEP CONVECTION.  THE FORWARD SPEED OF IDA HAS SLOWED TO
 ABOUT 11 KT.  THE DYNAMICAL MODEL GUIDANCE FORECASTS A CONTINUED
 REDUCTION IN THE FORWARD MOTION OF THE STORM AND A TURN TOWARD THE
 EAST AFTER LANDFALL.  THE NHC FORECAST IS CLOSE TO THE PREVIOUS
 ADVISORY THROUGH 12 HOURS AND IS THEN ADJUSTED A LITTLE NORTHWARD
 CLOSER TO THE MODEL CONSENSUS.
 
 THE AIRCRAFT HAS RECENTLY MEASURED A PEAK 850 MB FLIGHT-LEVEL WIND
 OF 71 KT AND A SMFR SURFACE WIND OF 51 KT.  THIS SUPPORTS AN
 INITIAL INTENSITY OF 55 KT.  IDA SHOULD GRADUALLY WEAKEN THROUGH
 LANDFALL DUE TO INCREASING SHEAR AND COOLER SSTS.  ONCE INLAND THE
 CYCLONE WILL WEAKEN AT A FASTER RATE AND BECOME EXTRATROPICAL
 SHORTLY THEREAFTER.  MOST OF THE GLOBAL MODELS SHOW THE CYCLONE
 BEING ABSORBED BY A FRONTAL BOUNDARY IN 36-48 HOURS AND SO DOES THE
 OFFICIAL FORECAST. 
    
 THE LOCATION AND TIMING OF IDA'S LANDFALL WILL HAVE LITTLE
 SIGNIFICANCE SINCE THE TROPICAL STORM FORCE WINDS COVER A LARGE
 AREA AND MOST OF THE HEAVIER RAINFALL IS ALREADY SPREADING ONSHORE.
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      10/0300Z 29.3N  88.6W    55 KT
  12HR VT     10/1200Z 30.8N  87.9W    40 KT...EXTRATROPICAL
  24HR VT     11/0000Z 31.5N  86.5W    30 KT...EXTRATROPICAL
  36HR VT     11/1200Z 31.3N  84.8W    25 KT...EXTRATROPICAL
  48HR VT     12/0000Z...DISSIPATED
  
 $$
 FORECASTER BROWN/BERG