Tropical Storm INGRID

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TROPICAL STORM INGRID DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL082007
500 AM EDT FRI SEP 14 2007
 
LATEST CONVENTIONAL SATELLITE IMAGERY AND A 0452 UTC AMSU-B
MICROWAVE PASS SUGGEST THAT THE CENTER OF CIRCULATION LIES BENEATH
THE LARGE BURST OF DEEP CONVECTION.  DVORAK INTENSITY ESTIMATES
FROM TAFB AND SAB ARE 3.0/45 KT AND 2.5/35 KT RESPECTIVELY. SINCE A
NOAA HURRICANE HUNTER PLANE CONDUCTING ANOTHER RESEARCH MISSION IS
CURRENTLY EN ROUTE TO INVESTIGATE THE CYCLONE...I WILL HOLD OFF
INCREASING THE INITIAL INTENSITY UNTIL A MORE ACCURATE MEASUREMENT
CAN BE TAKEN.  SO...INGRID WILL BE MAINTAINED AS A 35 KT TROPICAL
STORM FOR THIS ADVISORY.

THE PRIMARY MECHANISM THAT WILL AFFECT THE FUTURE INTENSITY OF
INGRID WILL BE THE AMOUNT OF SHEAR THE CYCLONE ENCOUNTERS OVER THE
NEXT 5 DAYS.  ABOUT 10-15 KNOTS OF WEST-SOUTHWESTERLY SHEAR IS
CURRENTLY AFFECTING INGRID...WHICH SHOULD PERSIST FOR THE NEXT
24-36 HOURS. THEREAFTER...THE SHEAR IS EXPECTED TO STRENGTHEN
HAMPERING INGRID FROM INTENSIFYING FURTHER.  THE OFFICIAL INTENSITY
FORECAST ALLOWS FOR SOME STRENGTHENING IN THE NEAR TERM FOLLOWED BY
GRADUAL WEAKENING.  THIS FOLLOWS CLOSELY WITH THE PREVIOUS FORECAST
AND IS CONSISTENT WITH A BLEND OF THE SHIPS/LGE AND FSSE INTENSITY
GUIDANCE. 
 
THE INITIAL MOTION IS ESTIMATED AROUND 300/6.  INGRID IS IN A WEAK
STEERING ENVIRONMENT WITH A WEAK RIDGE POSITIONED TO ITS NORTHEAST
AND A MID- TO UPPER-LEVEL LOW LOCATED TO ITS NORTH. MODEL GUIDANCE
IS IN OVERALL AGREEMENT THAT THE UPPER LOW WILL CONTINUE TO MOVE
SOUTHWESTWARD OVER THE NEXT SEVERAL DAYS AND GRADUALLY WEAKEN.  
BOTH THE STRENGTH OF THE UPPER-LEVEL LOW AND THAT OF INGRID WILL
DETERMINE THE DEGREE OF STEERING THE CYCLONE WILL TAKE TOWARD THE
NORTHWEST.  SINCE INGRID IS FORECAST TO REMAIN A RELATIVELY WEAK
CYCLONE IN A SHEARED ENVIRONMENT...THE OFFICIAL TRACK FORECAST
MAINTAINS A WEST-NORTHWEST MOTION THAT IS SLIGHTLY NORTH OF THE
PREVIOUS TRACK BUT SOUTH OF THE DYNAMICAL MODEL CONSENSUS. 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      14/0900Z 15.1N  49.2W    35 KT
 12HR VT     14/1800Z 15.5N  50.0W    40 KT
 24HR VT     15/0600Z 16.1N  51.1W    40 KT
 36HR VT     15/1800Z 16.7N  52.3W    40 KT
 48HR VT     16/0600Z 17.3N  53.7W    35 KT
 72HR VT     17/0600Z 18.5N  56.5W    35 KT
 96HR VT     18/0600Z 20.0N  58.5W    30 KT
120HR VT     19/0600Z 21.5N  60.5W    30 KT
 
$$
FORECASTER MAINELLI
 
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