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| #531638 (Received by flhurricane at: 10:41 PM 03.Aug.2012) TCDAT5 TROPICAL STORM ERNESTO DISCUSSION NUMBER 10 NWS NATIONAL HURRICANE CENTER MIAMI FL AL052012 1100 PM AST FRI AUG 03 2012 CONVECTION HAS BECOME MORE CONCENTRATED NEAR THE CENTER OF ERNESTO DURING THE PAST SEVERAL HOURS. HOWEVER...SATELLITE INTENSITY ESTIMATES AND AN ABBREVIATED HURRICANE HUNTER MISSION SUGGEST THAT THIS HAS NOT YET RESULTED IN INTENSIFICATION. THE INITIAL INTENSITY REMAINS 45 KT...AND THE CENTRAL PRESSURE OF 1003 MB IS BASED ON EXTRAPOLATION OF THE HURRICANE HUNTER DATA. ANALYSIS FROM CIMSS AT THE UNIVERSITY OF WISCONSIN SUGGEST THAT VERTICAL WIND SHEAR IS DECREASING OVER ERNESTO...AND THE OUTFLOW HAS IMPROVED IN THE WESTERN SEMICIRCLE. THE INITIAL MOTION IS 275/16...A LITTLE SLOWER THAN BEFORE. A STRONG LOW/MID-LEVEL SUBTROPICAL RIDGE TO THE NORTH OF ERNESTO SHOULD KEEP THE CYCLONE ON A GENERAL WESTWARD TRACK FOR THE NEXT 36-48 HR...AND THE NEW FORECAST TRACK IS SIMILAR TO THE OLD TRACK DURING THIS PERIOD. AFTER THAT TIME...THE TRACK FORECAST BECOMES LOWER CONFIDENCE. THE GLOBAL MODELS FORECAST A DEVELOPING MID/ UPPER-LEVEL TROUGH OVER THE EASTERN UNITED STATES FROM 72-120 HR... WHICH IS EXPECTED TO CAUSE A WEAKNESS IN THE RIDGE OVER THE THE NORTHERN GULF OF MEXICO AND THE ADJACENT LAND AREAS. THE GFDL... UKMET...AND NOGAPS MODELS RESPOND TO THIS BY FORECASTING ERNESTO TO MOVE NORTHWESTWARD NEAR THE YUCATAN CHANNEL INTO THE SOUTHERN GULF OF MEXICO. ON THE OTHER HAND...THE ECMWF AND GFS FORECAST ERNESTO TO BE TOO FAR SOUTH TO RESPOND TO THE WEAKNESS...AND THUS SHOW THE CYCLONE MOVING INLAND OVER THE SOUTHERN YUCATAN PENINSULA OR CENTRAL AMERICA. BASED ON THE PREMISE THAT ERNESTO WILL BE FAR ENOUGH NORTH AND STRONG ENOUGH TO RESPOND TO THE WEAKNESS...THE LATTER PART OF THE NEW FORECAST TRACK IS NUDGED A LITTLE TO THE NORTH OF THE PREVIOUS FORECAST. THE INTENSITY GUIDANCE REMAINS VERY DIVERGENT. THE STATISTICAL- DYNAMICAL MODELS FORECAST SIGNIFICANT INTENSIFICATION...WITH THE LGEM CALLING FOR ERNESTO TO BECOME A MAJOR HURRICANE IN 96 HR. THE DYNAMICAL MODELS OFFER A DISSENTING VIEW...WITH THE GFDL AND HWRF PREDICTING LITTLE CHANGE IN STRENGTH UNTIL ABOUT 96 HR. IN ADDITION...THE ECMWF FORECASTS ERNESTO TO REMAIN VERY WEAK. IT IS UNCLEAR WHAT ARE THE NEGATIVE FACTORS THAT THE DYNAMICAL MODELS ARE SEEING...SINCE THE SHEAR IS FORECAST TO BE LIGHT AFTER 24 HR AND THE SEA SURFACE TEMPERATURES ARE VERY WARM. THE NEW INTENSITY FORECAST SHOWS A LITTLE MORE INTENSIFICATION THAN THE PREVIOUS FORECAST THROUGH 48 HR. AFTER THAT...IT IS THE SAME AS THE PREVIOUS FORECAST DUE TO THE DIVERGENT GUIDANCE. INTERESTS IN JAMAICA SHOULD MONITOR THE PROGRESS OF ERNESTO...AS A TROPICAL STORM WATCH COULD BE REQUIRED FOR PORTIONS OF THE ISLAND ON SATURDAY. FORECAST POSITIONS AND MAX WINDS INIT 04/0300Z 13.9N 65.6W 45 KT 50 MPH 12H 04/1200Z 14.2N 67.9W 50 KT 60 MPH 24H 05/0000Z 14.7N 71.3W 55 KT 65 MPH 36H 05/1200Z 15.4N 74.8W 55 KT 65 MPH 48H 06/0000Z 16.1N 77.9W 60 KT 70 MPH 72H 07/0000Z 17.5N 82.0W 65 KT 75 MPH 96H 08/0000Z 19.5N 85.5W 75 KT 85 MPH 120H 09/0000Z 22.0N 88.9W 65 KT 75 MPH $$ FORECASTER BEVEN |
