000
WTNT41 KNHC 060838
TCDAT1
TROPICAL DEPRESSION IDA DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL112009
400 AM EST FRI NOV 06 2009
 
THE DEEP CONVECTION IS NOW LARGELY CONFINED TO THE NORTHERN
SEMICIRCLE OF THE CIRCULATION...WITH THE COLDEST TOPS FOUND IN A
BAND EXTENDING FROM EASTERN HONDURAS INTO THE NORTHWESTERN
CARIBBEAN. THE INITIAL INTENSITY IS HELD AT 30 KT FOR THIS
ADVISORY...BUT IDA WILL LIKELY WEAKEN A LITTLE MORE TODAY WHILE THE
CENTER REMAINS OVER LAND.  IT NOW APPEARS THAT THE CENTER OF IDA
WILL REMAIN EAST OF THE HIGHEST TERRAIN IN NICARAGUA AND HONDURAS
BEFORE IT EMERGES OVER THE NORTHWEST CARIBBEAN SEA IN ABOUT 24
HOURS.  IF IDA SURVIVES UNTIL THEN IT WILL HAVE AN OPPORTUNITY TO
RESTRENGTHEN.  THERE IS SIGNIFICANT SPREAD IN THE INTENSITY
GUIDANCE...WITH THE GFDL AND HWRF MODELS SHOWING IDA REACHING
HURRICANE INTENSITY AS IT ENTERS THE GULF OF MEXICO IN 3 TO 4 DAYS.
CONVERSELY...THE SHIPS MODEL SHOWS ONLY MODEST STRENGTHENING WHILE
THE LGEM SHOWS GRADUAL WEAKENING.  THE OFFICIAL FORECAST IS CLOSER
TO THE LATTER SCENARIO AS THE UPPER-LEVEL ENVIRONMENT DEPICTED BY
THE GLOBAL MODELS DOES NOT APPEAR CONDUCIVE FOR SIGNIFICANT
INTENSIFICATION ONCE IDA MOVES INTO THE GULF OF MEXICO.
 
THE INITIAL MOTION CONTINUES TO NUDGE TO THE RIGHT AND IS ESTIMATED
TO BE 350/05 AS IDA MOVES AROUND THE WESTERN PERIPHERY OF A WEAK
MID-LEVEL RIDGE OVER THE CARIBBEAN SEA.  A GENERAL NORTHWARD TO
NORTH-NORTHWESTWARD MOTION IS EXPECTED OVER THE NEXT 4 DAYS BRINGING
IDA INTO THE YUCATAN CHANNEL AND THEN INTO THE CENTRAL GULF OF
MEXICO.  BY THE END OF THE FORECAST PERIOD...THE GLOBAL MODELS SHOW
IDA INTERACTING WITH A MID- TO UPPER-LEVEL TROUGH THAT DIGS INTO
THE NORTHERN GULF OF MEXICO...AND MANY OF THE MODELS RESPOND BY
TURNING IDA NORTHEASTWARD.  THE OFFICIAL TRACK FORECAST IS
BASICALLY AN UPDATE OF THE PREVIOUS ONE AND REMAINS NEAR THE MIDDLE
OF THE GUIDANCE ENVELOPE.
 
THE BIGGEST IMPACT OF THIS IDA IN THE NEXT DAY OR SO WILL LIKELY BE
LIFE-THREATENING FLASH FLOODS AND MUD SLIDES CAUSED BY EXTREMELY
HEAVY RAIN OVER PORTIONS OF NICARAGUA AND HONDURAS.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      06/0900Z 14.4N  84.1W    30 KT
 12HR VT     06/1800Z 15.2N  84.2W    25 KT...INLAND
 24HR VT     07/0600Z 16.4N  84.4W    30 KT...OVER WATER
 36HR VT     07/1800Z 17.4N  84.8W    35 KT
 48HR VT     08/0600Z 18.7N  85.4W    40 KT
 72HR VT     09/0600Z 21.5N  86.7W    45 KT
 96HR VT     10/0600Z 24.0N  87.5W    45 KT
120HR VT     11/0600Z 27.0N  86.5W    45 KT
 
$$
FORECASTER CANGIALOSI/BRENNAN