Tropical Storm INGRID

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TROPICAL STORM INGRID DISCUSSION NUMBER   7
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL082007
1100 PM EDT THU SEP 13 2007

A NOAA HURRICANE HUNTER PLANE HAS BEEN ON A RESEARCH MISSION THIS
EVENING AND FOUND 35 KT WINDS USING THE ON-BOARD STEPPED-FREQUENCY
MICROWAVE RADIOMETER (SFMR).  THESE WINDS MATCH UP FAIRLY WELL TO A
RECENT QUIKSCAT PASS THAT SUGGESTED WINDS OF ABOUT 35 KT AND
SUBJECTIVE DVORAK SATELLITE ESTIMATES OF 35 KT.  THE INITIAL
INTENSITY IS RAISED TO 35 KT...MAKING THIS SYSTEM THE NINTH NAMED
STORM OF THE YEAR.  

MODERATE WESTERLY VERTICAL WIND SHEAR CONTINUES TO AFFECT INGRID. 
MOST OF THE DYNAMICAL MODELS KEEP THE SHEAR ABOUT THE SAME FOR THE
NEXT 24 HOURS...WHICH SHOULD ALLOW FOR A MODEST INCREASE IN
STRENGTH.  THEREAFTER...WESTERLY SHEAR SHOULD INTENSIFY...LIKELY
CAUSING A WEAKENING OF INGRID.  THE OFFICIAL FORECAST KEEPS THE
SYSTEM A TROPICAL STORM FOR THE NEXT FEW DAYS...AND COULD BE A
LITTLE TOO HIGH IN THE LONGER RANGE AS GLOBAL MODELS ARE SHOWING
NEARLY 30 KT OF WESTERLY SHEAR IN THE STORM'S PATH. 

THE INITIAL MOTION HAS TURNED A LITTLE MORE TO THE RIGHT TONIGHT...
ESTIMATED AT 300/5.  THE TRACK FORECAST IS TRICKY AS IT PROBABLY
HAS A STRONG DEPENDENCE ON THE FUTURE INTENSITY OF INGRID.  WATER
VAPOR IMAGES SHOW A MIDDLE- TO UPPER-LEVEL LOW DIGGING
SOUTHWESTWARD TO THE NORTH OF THE SYSTEM.  THIS LOW HAS CAUSED A
VERY WEAK STEERING ENVIRONMENT WITH ONLY SLIGHT MIDDLE-LEVEL RIDGING
REMAINING TO THE NORTHEAST OF THE TROPICAL CYCLONE.  A STRONGER
TROPICAL CYCLONE WOULD PROBABLY BE MORE RESPONSIVE TO THE
LOW...AND MOVE FARTHER TO THE NORTH OF THE OFFICIAL FORECAST.  IT
IS ASSUMED THAT INGRID WILL REMAIN WEAK AND STAY ON THE SOUTHERN
SIDE OF THE GUIDANCE ENVELOPE FOR NOW.  
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      14/0300Z 14.7N  48.7W    35 KT
 12HR VT     14/1200Z 15.1N  49.4W    40 KT
 24HR VT     15/0000Z 15.6N  50.4W    40 KT
 36HR VT     15/1200Z 16.2N  51.6W    35 KT
 48HR VT     16/0000Z 16.7N  52.9W    35 KT
 72HR VT     17/0000Z 17.8N  56.0W    35 KT
 96HR VT     18/0000Z 19.0N  58.5W    30 KT
120HR VT     19/0000Z 20.5N  60.5W    30 KT
 
$$
FORECASTER BLAKE
 
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