924 
 WTNT41 KNHC 050836
 TCDAT1
 TROPICAL STORM IDA DISCUSSION NUMBER   4
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL112009
 400 AM EST THU NOV 05 2009
  
 THE SATELLITE PRESENTATION OF IDA HAS CONTINUED TO IMPROVE OVER THE
 PAST FEW HOURS. EARLIER THERE WAS A LARGE EXPANSION OF COLD CLOUD
 TOPS IN A SYMMETRIC CENTRAL DENSE OVERCAST WHILE IN THE LAST HOUR OR
 TWO THE COLDEST TOPS HAVE TAKEN ON A MORE BANDED APPEARANCE. DVORAK
 INTENSITY ESTIMATES AT 0600 UTC WERE 55 KT FROM TAFB AND SAB...
 HOWEVER AIRCRAFT RECONNAISSANCE FOUND THAT IDA WAS ALREADY THAT
 STRONG YESTERDAY WHEN IT HAD A MUCH LESS IMPRESSIVE SATELLITE
 APPEARANCE.  THEREFORE...THE INITIAL INTENSITY IS RAISED TO 60 KT
 FOR THIS ADVISORY.  WHILE THERE IS ONLY A SMALL WINDOW FOR
 ADDITIONAL STRENGTHENING...THE HURRICANE WATCH FOR PORTIONS OF THE
 COAST OF NICARAGUA REFLECTS THE SMALL CHANCE THAT IDA COULD REACH
 HURRICANE STATUS AS IS MAKES LANDFALL.  AFTER LANDFALL...WEAKENING
 IS FORECAST AS THE CENTER IS EXPECTED TO REMAIN OVER LAND FOR THE
 NEXT COUPLE OF DAYS.  THE TRACK FORECAST TAKES IDA BACK OVER THE
 NORTHWESTERN CARIBBEAN SEA AFTER 48 HOURS...AND THE INTENSITY
 FORECAST SHOWS SOME STRENGTHENING AT 72 HOURS AND BEYOND.  HOWEVER
 ...THERE IS A LARGE DEGREE OF UNCERTAINTY AT THIS TIME RANGE...SINCE
 IDA MAY NOT SURVIVE LONG ENOUGH TO REACH WATER AGAIN.
  
 THE INITIAL MOTION ESTIMATE IS 310/06. THROUGH 48 HOURS THE
 MULTI-MODEL CONSENSUS IS IN GOOD AGREEMENT WITH THE PREVIOUS
 FORECAST...AS IDA IS EXPECTED TO TURN NORTHWARD BETWEEN A WEAK
 MID-LEVEL RIDGE OVER THE NORTH-CENTRAL CARIBBEAN SEA AND A
 WEAK TROUGH OVER THE SOUTHERN GULF OF MEXICO.  BEYOND THAT TIME...
 MUCH OF THE GUIDANCE HAS SHIFTED WESTWARD WITH LARGE DIFFERENCES IN 
 FORWARD SPEED AS WHATEVER IS LEFT OF IDA INTERACTS WITH A MID-LEVEL
 TROUGH DIGGING INTO THE NORTHWESTERN GULF OF MEXICO.  GIVEN THE
 LARGE SPREAD IN THE GUIDANCE...A SLOW NORTH-NORTHWESTWARD MOTION IS
 SHOWN AT DAYS 3 THROUGH 5.  THIS IS IN GOOD AGREEMENT WITH THE
 PREVIOUS FORECAST AND ON THE EASTERN SIDE OF THE GUIDANCE
 ENVELOPE...WITH THE EXCEPTION OF THE GFDL WHICH IS A FAR EASTERN
 OUTLIER.
  
 THE BIGGEST IMPACT OF THIS SLOW-MOVING SYSTEM WILL LIKELY BE
 LIFE-THREATENING FLASH FLOODS AND MUD SLIDES CAUSED BY EXTREMELY
 HEAVY RAIN OVER PORTIONS OF NICARAGUA AND HONDURAS OVER THE NEXT
 COUPLE OF DAYS. 
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      05/0900Z 12.8N  83.4W    60 KT
  12HR VT     05/1800Z 13.3N  83.9W    45 KT...INLAND
  24HR VT     06/0600Z 13.9N  84.3W    35 KT...INLAND
  36HR VT     06/1800Z 14.7N  84.6W    30 KT...INLAND
  48HR VT     07/0600Z 15.7N  84.8W    25 KT...INLAND
  72HR VT     08/0600Z 18.0N  85.5W    35 KT...OVER WATER
  96HR VT     09/0600Z 20.0N  86.0W    40 KT
 120HR VT     10/0600Z 22.0N  87.0W    45 KT
  
 $$
 FORECASTER BRENNAN/CANGIALOSI