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#619277 (Received by flhurricane at: 10:50 PM 24.Jul.2013) TCDAT4 TROPICAL STORM DORIAN DISCUSSION NUMBER 4 NWS NATIONAL HURRICANE CENTER MIAMI FL AL042013 1100 PM AST WED JUL 24 2013 INFRARED SATELLITE IMAGERY INDICATES THAT THE LOW-LEVEL CENTER OF DORIAN HAS BECOME MORE EMBEDDED BENEATH THE COLD CONVECTIVE TOPS. DVORAK ESTIMATES FROM TAFB AND SAB ARE NOW A CONSENSUS T3.0/45 KT WHILE UW-CIMSS OBJECTIVE ESTIMATES HAVE INCREASED TO 50-55 KT. BASED ON RECENT ASCAT DATA...HOWEVER...DORIAN MAY NOT BE PRODUCING SURFACE WINDS ANY HIGHER THAN ABOUT 40 KT. THIS COULD BE DUE TO THE RESOLUTION OF ASCAT SINCE DORIAN IS A SMALL CYCLONE...SO THE INTENSITY IS BEING HELD AT 45 KT ON THIS ADVISORY. THE MOTION REMAINS 285/17 KT WITH DORIAN LYING ON THE WESTERN PERIPHERY OF A NORTHWEST-TO-SOUTHEAST ORIENTED MID-LEVEL RIDGE. A MID-LEVEL ANTICYCLONE IS EXPECTED TO DETACH FROM THE RIDGE AND MOVE WESTWARD TO THE NORTH OF DORIAN FOR THE ENTIRE FORECAST PERIOD... KEEPING THE TROPICAL CYCLONE ON A QUICK WEST-NORTHWESTWARD TO WESTWARD TRAJECTORY. THERE IS VERY LITTLE SPREAD AMONG THE TRACK MODELS ON THIS CYCLE...AND THE NEW NHC TRACK FORECAST IS VERY SIMILAR TO THE PREVIOUS TRACK. AN ANIMATION OF SEA SURFACE TEMPERATURE FIELDS INDICATES THAT THE WATERS AHEAD OF DORIAN HAVE BEEN WARMING OVER THE PAST FEW DAYS...AND IT APPEARS THAT THE CYCLONE WILL LIKELY REMAIN OVER WATERS A LITTLE WARMER THAN PREVIOUSLY ANTICIPATED. IN ADDITION...DORIAN SHOULD BE MOVING FAST ENOUGH THAT UPWELLING OF COOLER WATER SHOULD NOT BE MUCH OF A FACTOR. THEREFORE...THE NEW NHC INTENSITY FORECAST NO LONGER SHOWS SHORT-TERM WEAKENING AND INSTEAD INDICATES SLIGHT STRENGTHENING THROUGH DAY 5. THIS FORECAST IS JUST A LITTLE HIGHER THAN THE FLORIDA STATE SUPERENSEMBLE AND THE INTENSITY CONSENSUS...BUT NOT NEARLY AS HIGH AS THE STATISTICAL-DYNAMICAL SHIPS AND LGEM MODELS. CONFIDENCE IN THE INTENSITY FORECAST IS RATHER LOW AT THIS POINT UNTIL WE KNOW HOW DORIAN FARES OVER THE NEXT DAY OR TWO. FORECAST POSITIONS AND MAX WINDS INIT 25/0300Z 15.1N 33.2W 45 KT 50 MPH 12H 25/1200Z 15.7N 35.7W 50 KT 60 MPH 24H 26/0000Z 16.5N 39.0W 50 KT 60 MPH 36H 26/1200Z 17.2N 42.5W 50 KT 60 MPH 48H 27/0000Z 17.9N 46.3W 50 KT 60 MPH 72H 28/0000Z 19.0N 54.0W 55 KT 65 MPH 96H 29/0000Z 20.0N 60.5W 55 KT 65 MPH 120H 30/0000Z 20.5N 65.5W 55 KT 65 MPH $$ FORECASTER BERG |