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| #150716 (Received by flhurricane at: 10:31 PM 13.Sep.2007) TCDAT3 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 |
