Flhurricane.com - Central Florida Hurricane Center - Tracking Storms since 1995Hurricanes Without the Hype! Since 1995
The Atlantic is quiet
|
Show Selection: |
| #471279 (Received by flhurricane at: 3:38 PM 08.Nov.2011) TCDAT4 TROPICAL STORM SEAN DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL AL192011 500 PM AST TUE NOV 08 2011 CONVECTION HAS FORMED NEAR THE CENTER OF SEAN THIS AFTERNOON WITH A BANDING FEATURE PERSISTING IN THE NORTHEASTERN QUADRANT. SINCE THE STORM IS A LITTLE FARTHER FROM THE UPPER-LEVEL LOW...WITH A WARM CORE APPARENT ON AMSU ANALYSES AND A SMALLER RADIUS OF MAXIMUM WINDS AS SEEN IN ASCAT DATA...SEAN NOW HAS ENOUGH CHARACTERISTICS TO BE CONSIDERED TROPICAL. THE MAXIMUM WINDS ARE SET TO 45 KT...IN AGREEMENT WITH THE TAFB DVORAK ESTIMATE AND EARLIER ASCAT WINDS. WHILE THE REGIONAL HURRICANE MODELS DO NOT SHOW MUCH INTENSIFICATION OF SEAN...THE SHEAR REMAINS RELATIVELY LIGHT FOR THE NEXT 36 HR OR SO WHILE THE SYSTEM IS OVER MARGINAL SSTS. SINCE THE STORM IS EMBEDDED WITHIN COLDER-THAN-AVERAGE UPPER-AIR TEMPERATURES...THE SST THRESHOLD FOR TROPICAL CYCLONE STRENGTHENING IS LOWER THAN USUAL...AND SOME FURTHER STRENGTHENING IS ANTICIPATED. THE NEW NHC FORECAST IS HIGHER THAN THE PREVIOUS ONE...AND REMAINS IN LINE WITH THE SHIPS/LGEM MODELS AND THE EXPERIMENTAL SPC3 ENSEMBLE SHIPS GUIDANCE. IN ABOUT TWO DAYS... SEAN SHOULD ENCOUNTER A MORE HOSTILE UPPER-AIR ENVIRONMENT...WHICH SHOULD INDUCE WEAKENING. THE CENTER OF THE CYCLONE HAS BEEN WOBBLING AROUND FOR QUITE SOME TIME...BUT IT APPEARS THAT A MOTION TOWARD THE WEST-NORTHWEST HAS BEGUN. THIS GENERAL TRACK IS EXPECTED TO CONTINUE THROUGH TOMORROW AS A RIDGE MOVES THROUGH THE WESTERN ATLANTIC. THEREAFTER...THE STORM SHOULD TURN TOWARD THE NORTH AND NORTHEAST BY THURSDAY AHEAD OF A DEEP TROUGH OVER THE EASTERN UNITED STATES. IT SEEMS THAT BEING ON THE RIGHT SIDE OF THE GUIDANCE EARLIER WAS A GOOD CALL... AS MOST OF THE MODELS HAVE SHIFTED IN THAT DIRECTION...APPARENTLY BECAUSE OF FLATTER MID-LATITUDE FLOW FORECAST TO AFFECT SEAN. ONLY COSMETIC CHANGES WERE MADE TO THE NHC TRACK FOR THE FIRST COUPLE OF DAYS...WITH A SHIFT TO THE SOUTHEAST MADE AT DAY 3...BETWEEN THE ECMWF AND GFS MODELS. ALL OF THE GLOBAL MODELS SHOW THE STORM BEING ABSORBED BY A FRONTAL BOUNDARY BY DAY 4...AND THIS SCENARIO IS REFLECTED IN THE NHC FORECAST. FORECAST POSITIONS AND MAX WINDS INIT 08/2100Z 27.8N 69.8W 45 KT 50 MPH 12H 09/0600Z 27.9N 70.2W 50 KT 60 MPH 24H 09/1800Z 28.4N 70.4W 50 KT 60 MPH 36H 10/0600Z 29.0N 70.5W 55 KT 65 MPH 48H 10/1800Z 29.9N 69.7W 50 KT 60 MPH 72H 11/1800Z 34.0N 64.0W 45 KT 50 MPH 96H 12/1800Z...ABSORBED $$ FORECASTER BLAKE |
