Tropical Depression INGRID

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TROPICAL DEPRESSION INGRID DISCUSSION NUMBER  17
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL082007
1100 AM EDT SUN SEP 16 2007

INGRID IS MAINTAINING ITS INTENSITY DESPITE THE HOSTILE UPPER-LEVEL
FLOW.  IN FACT...THE APPEARANCE OF THE SYSTEM IS LESS DISORGANIZED
THAN IT WAS 24 HOURS AGO...WITH THE CENTER NO LONGER EXPOSED FROM
THE DEEP CONVECTION.  THE CURRENT INTENSITY ESTIMATE REMAINS AT 30
KT IN AGREEMENT WITH A DVORAK ESTIMATE FROM TAFB.  ACCORDING TO THE
LATEST GFS RUN...VERTICAL SHEAR IS FORECAST TO REMAIN ABOVE 20 KT
FOR THE NEXT 48 HOURS.  THIS WOULD SEEM TO PRECLUDE ANY SIGNIFICANT
RE-STRENGTHENING OVER THE NEXT DAY OR TWO. HOWEVER THE CONSENSUS OF
SHIPS...THE GFDL...AND THE HWRF MODEL INDICATES THAT INGRID WILL
EVENTUALLY REGAIN TROPICAL STORM STRENGTH...AS THE UPPER-LEVEL
ENVIRONMENT IS FORECAST TO BECOME LESS HOSTILE LATE IN THE FORECAST
PERIOD.  FOR THE SAKE OF CONTINUITY WITH PREVIOUS FORECASTS THAT
INDICATED DISSIPATION BY DAY 5...THE CURRENT NHC INTENSITY FORECAST
MERELY MAINTAINS INGRID AT ITS CURRENT STRENGTH.  HOWEVER THE NEXT
NHC ADVISORY PACKAGE MAY NEED TO SHOW SOME RESTRENGTHENING. 

BASED ON GEOSTATIONARY AND MICROWAVE SATELLITE FIXES...THE INITIAL
MOTION IS ONLY SLIGHTLY NORTH OF WEST...280/10.  HOWEVER...THE
MID-LEVEL RIDGE TO THE NORTH OF INGRID IS FORECAST TO WEAKEN.  THIS
SHOULD INDUCE A TURN TO THE RIGHT OVER THE NEXT SEVERAL DAYS...AS
INDICATED BY THE MAJORITY OF THE TRACK GUIDANCE MODELS.  IN 4-5
DAYS A TROUGH DROPPING DOWN OVER THE WESTERN ATLANTIC IS EXPECTED
TO TURN INGRID NORTHWARD.  HOWEVER THE STEERING CURRENTS ARE NOT
VERY WELL DEFINED SO A SLOW MOTION OF ONLY 4-5 KT IS INDICATED BY
THE OFFICIAL TRACK FORECAST LATE IN THE PERIOD. THIS IS IN
AGREEMENT WITH THE DYNAMICAL MODEL CONSENSUS.

SINCE INGRID HAS MOVED SOMEWHAT MORE WESTWARD THAN EXPECTED...AND
THERE IS LIMITED SKILL IN FORECASTING INTENSITY CHANGE...INTERESTS
IN THE NORTHERN LEEWARD ISLANDS SHOULD MONITOR THE PROGRESS OF THIS
SYSTEM.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      16/1500Z 17.2N  57.9W    30 KT
 12HR VT     17/0000Z 17.7N  59.1W    30 KT
 24HR VT     17/1200Z 18.4N  60.3W    30 KT
 36HR VT     18/0000Z 19.2N  61.3W    30 KT
 48HR VT     18/1200Z 20.0N  62.2W    30 KT
 72HR VT     19/1200Z 21.5N  63.5W    30 KT
 96HR VT     20/1200Z 23.0N  64.5W    30 KT
120HR VT     21/1200Z 24.5N  64.5W    30 KT
 
$$
FORECASTER PASCH
 
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