Tropical Depression INGRID

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TROPICAL DEPRESSION INGRID DISCUSSION NUMBER  18
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL082007
500 PM EDT SUN SEP 16 2007

AFTER BECOMING A LITTLE BETTER ORGANIZED THIS MORNING...THE
SATELLITE PRESENTATION OF INGRID HAS AGAIN DETERIORATED.  THE CLOUD
PATTERN HAS BECOME QUITE RAGGED...DEEP CONVECTION IS LIMITED...AND
THE LOW CLOUD LINES DEPICTING THE CIRCULATION HAVE BECOME
INDISTINCT.  MOREOVER...A NUMBER OF ARC CLOUDS...IMPLYING LOW-LEVEL
DIVERGENCE...ARE SEEN EMANATING FROM THE WESTERN PORTION OF THE
SYSTEM.  THE INTENSITY IS KEPT AT 30 KT IN ACCORDANCE WITH THE TAFB
DVORAK ESTIMATE.  WESTERLY SHEAR IS FORECAST TO REMAIN RATHER
STRONG FOR THE NEXT DAY OR SO...WHICH MAKES SIGNIFICANT
INTENSIFICATION UNLIKELY IN THE SHORT TERM.  INDEED IF THE CURRENT
DISORGANIZING TREND CONTINUES...INGRID WILL WEAKEN.  HOWEVER SOME
OF THE GLOBAL MODELS FORECAST A SLIGHTLY MORE FAVORABLE UPPER-LEVEL
FLOW TO EVOLVE LATER IN THE FORECAST PERIOD.  THEREFORE...IF INGRID
SURVIVES FOR THE NEXT COUPLE OF DAYS...IT COULD BEGIN TO
RESTRENGTHEN IN 3-4 DAYS.  THE OFFICIAL INTENSITY FORECAST ALLOWS
FOR THIS POSSIBILITY...AND IS SLIGHTLY BELOW THE LATEST LGEM AND
HWRF GUIDANCE AT THAT TIME FRAME.  ALTERNATIVELY THE GFDL NOW
DISSIPATES THE CYCLONE WITHIN 36 HOURS.

THE LOW-LEVEL CENTER IS DIFFICULT TO FIND AND THERE IS A LOT OF
SPREAD IN LOCATION ESTIMATES THIS AFTERNOON.  CONSEQUENTLY THE
INITIAL MOTION ESTIMATE IS A RATHER UNCERTAIN 285/9.  THE STEERING
CURRENTS FOR INGRID ARE NOT WELL-DEFINED.  THE LOW- TO MID-LEVEL
RIDGE TO THE NORTH OF THE CYCLONE IS LIKELY TO WEAKEN DURING THE
NEXT DAY OR TWO...WHICH WOULD BRING ABOUT A GRADUAL TURN TO THE
RIGHT.  A MID-LEVEL TROUGH DROPPING INTO THE WEST-CENTRAL ATLANTIC
IN 3-4 DAYS MIGHT BE JUST A LITTLE TOO FAR EAST TO HAVE A DIRECT
INFLUENCE ON INGRID'S MOTION.  THE OFFICIAL TRACK FORECAST SLOWS
THE FORWARD SPEED TO LESS THAN 5 KT LATER IN THE PERIOD...AND IS
NOT FAR FROM THE CONU DYNAMICAL MODEL CONSENSUS.

INTERESTS IN THE NORTHERN LEEWARD ISLANDS SHOULD MONITOR THE
PROGRESS OF INGRID SINCE IT IS POSSIBLE FOR THE SYSTEM TO MOVE MORE
TO THE LEFT OF OUR FORECAST TRACK.  A NOAA HURRICANE HUNTER PLANE
IS SCHEDULED TO FLY A RESEARCH MISSION INTO THE CYCLONE AROUND 0000
UTC AND HOPEFULLY WILL BE ABLE TO PROVIDE A POSITION AND INTENSITY
ESTIMATE.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      16/2100Z 17.4N  58.6W    30 KT
 12HR VT     17/0600Z 17.8N  59.8W    30 KT
 24HR VT     17/1800Z 18.5N  61.0W    30 KT
 36HR VT     18/0600Z 19.3N  61.9W    30 KT
 48HR VT     18/1800Z 20.2N  62.7W    30 KT
 72HR VT     19/1800Z 21.2N  63.7W    30 KT
 96HR VT     20/1800Z 22.5N  65.0W    35 KT
120HR VT     21/1800Z 24.0N  66.0W    45 KT
 
$$
FORECASTER PASCH
 
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