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#40135 (Received by flhurricane at: 10:31 PM 16.Aug.2005) TCDAT4 HURRICANE IRENE DISCUSSION NUMBER 50 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 PM EDT TUE AUG 16 2005 A WARM SPOT WITHIN THE DEEP CONVECTION HAS STILL BEEN APPARENT FOR MUCH OF THE EVENING...ALTHOUGH OVERALL THE AMOUNT OF DEEP CONVECTION HAS DECREASED MARKEDLY OVER THE LAST 12 HOURS...AND THE PATTERN HAS DEGRADED DURING THE LAST COUPLE OF HOURS. IN ADDITION...WATER VAPOR IMAGERY SHOWS AN EROSION OF THE MOISTURE IN THE SOUTHWEST QUADRANT. DVORAK T-NUMBERS FROM TAFB AND SAB HAVE COME DOWN TO 4.0...AND THE INITIAL INTENSITY IS LOWERED TO 80 KT FOR THIS ADVISORY. IRENE CONTINUES TO BE LARGELY SHELTERED FROM THE STRONG BELT OF UPPER-LEVEL WESTERLIES THAT LIE NORTH OF ABOUT 38N LATITUDE. IT IS STILL EXPECTED THAT IRENE WILL BE IMPACTED BY MUCH STRONGER SHEAR ASSOCIATED WITH THESE WESTERLIES WITHIN 12-24 HOURS...AND THIS SHOULD CAUSE WEAKENING. THE SHIPS 48 HOUR FORECAST OF A 68 KT HURRICANE OVER 15C WATER IS DIFFICULT TO ACCEPT...AND THE OFFICIAL FORECAST IS CONSIDERABLY BELOW THIS GUIDANCE. A BAROCLINIC KICK FROM THE MID-LATITUDE TROUGH CURRENTLY OVER THE PROVINCE OF QUEBEC IS EXPECTED TO KEEP THE EXTRATROPICAL REMNANTS OF IRENE VIGOROUS UNTIL THE SYSTEM IS ABSORBED BY A LARGER EXTRATROPICAL LOW AFTER 48 HOURS. THE INITIAL MOTION IS 090/8. IRENE CONTINUES TO SLIDE SLOWLY EASTWARD SOUTH OF THE MAIN BELT OF THE WESTERLIES. AS THE AFOREMENTIONED MID-LATITUDE TROUGH APPROACHES IRENE'S LONGITUDE...THE FLOW IS EXPECTED TO TURN SOUTHWESTERLY AND IRENE SHOULD BEGIN TO ACCELERATE AHEAD OF THE TROUGH. OVER THE PAST COUPLE OF DAYS...THE GFDL HAS BEEN CONSISTENTLY...AND CORRECTLY... TO THE RIGHT OF THE GLOBAL MODELS AND THE CURRENT FORECAST IS ADJUSTED SOMEWHAT EASTWARD TO BE IN BETTER AGREEMENT WITH THE GFDL...ESPECIALLY IN THE FIRST 24 HOURS. FORECASTER FRANKLIN FORECAST POSITIONS AND MAX WINDS INITIAL 17/0300Z 36.6N 60.4W 80 KT 12HR VT 17/1200Z 37.1N 58.7W 70 KT 24HR VT 18/0000Z 39.0N 55.0W 65 KT 36HR VT 18/1200Z 43.3N 49.3W 55 KT...EXTRATROPICAL 48HR VT 19/0000Z 50.0N 42.0W 50 KT...EXTRATROPICAL 72HR VT 20/0000Z...ABSORBED BY EXTRATROPICAL LOW |