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| #382150 (Received by flhurricane at: 10:37 PM 09.Oct.2010) TCDAT2 TROPICAL STORM OTTO DISCUSSION NUMBER 16 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL172010 1100 PM AST SAT OCT 09 2010 CONVENTIONAL AND MICROWAVE SATELLITE IMAGERY INDICATE OTTO IS QUICKLY COMING UNRAVELED. CLOUD TOPS HAVE WARMED SIGNIFICANTLY AND THE OVERALL CONVECTIVE PATTERN HAS BECOME RATHER DISHEVELED LOOKING. THE INITIAL INTENSITY OF 60 KT IS BASED ON A BLEND OF SATELLITE CURRENT INTENSITY ESTIMATES OF T4.0/65 KT FROM TAFB AND T3.5/55 KT FROM SAB...AND OTTO IS NOW A TROPICAL STORM. THE CENTRAL PRESSURE IS BASED ON A PRESSURE REPORT OF 989.1 MB AT 23Z FROM DRIFTING BUOY 62905 THAT OTTO PASSED OVER OR VERY CLOSE TO. THE INITIAL MOTION ESTIMATE IS 060/33. OTTO CONTINUES TO ACCELERATE AHEAD OF A SHARP DEEP-LAYERED TROUGH MOVING ACROSS THE CENTRAL ATLANTIC. HOWEVER...ACCELERATION SHOULD LIKELY CEASE DURING THE NEXT 12 HOURS OR SO AS THE LOW- AND UPPER-LEVEL CIRCULATIONS DECOUPLE DUE TO VERTICAL SHEAR INCREASING TO MORE THAN 40 KT AND SSTS COOLING TO BELOW 23C. BY 36 HOURS....OTTO SHOULD BE STEERED BY THE WEAKER WESTERLY LOW-LEVEL FLOW AND SLOW DOWN AND TURN EASTWARD...FOLLOWED BY A SOUTHEASTWARD TURN AS THE CYCLONE ROUNDS THE TOP OF A MID-LEVEL RIDGE LOCATED WEST OF THE AZORES ISLANDS. THE NHC TRACK GUIDANCE IS IN GOOD AGREEMENT ON THIS SCENARIO AND THERE IS LESS SPREAD IN THE MODELS FOR THIS ADVISORY PACKAGE. THE OFFICIAL FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY...AND REMAINS SOUTH OF THE MODEL CONSENSUS AFTER 48 HOURS. INCREASING VERTICAL SHEAR...COMBINED WITH DECREASING SSTS AND DRY AIR ENTRAINMENT FROM THE WEST...SHOULD HASTEN THE WEAKENING PROCESS AND OTTO SHOULD TRANSITION TO AN EXTRATROPICAL CYCLONE IN 24 HOURS OR LESS. THE NHC INTENSITY FORECAST IS SIMILAR TO THE SHIPS/LGEM INTENSITY GUIDANCE. FORECAST POSITIONS AND MAX WINDS INITIAL 10/0300Z 33.9N 48.7W 60 KT 12HR VT 10/1200Z 36.3N 43.4W 50 KT 24HR VT 11/0000Z 39.7N 36.5W 45 KT...POST-TROP/EXTRATROP 36HR VT 11/1200Z 42.0N 31.4W 40 KT...POST-TROP/EXTRATROP 48HR VT 12/0000Z 43.5N 28.0W 40 KT...POST-TROP/EXTRATROP 72HR VT 13/0000Z 42.0N 25.0W 35 KT...POST-TROP/EXTRATROP 96HR VT 14/0000Z 39.0N 23.0W 30 KT...POST-TROP/EXTRATROP 120HR VT 15/0000Z 37.0N 21.5W 30 KT...POST-TROP/EXTRATROP $$ FORECASTER STEWART |
