000 WTPZ43 KNHC 140841 TCDEP3 TROPICAL STORM CARLOTTA DISCUSSION NUMBER 2 NWS NATIONAL HURRICANE CENTER MIAMI FL EP032012 200 AM PDT THU JUN 14 2012 CONVECTIVE BANDING FEATURES ASSOCIATED WITH TROPICAL DEPRESSION THREE-E HAVE INCREASED OVER THE PAST 6 HOURS...AND SATELLITE INTENSITY ESTIMATES ARE A CONSENSUS T2.5/35 KT FROM TAFB...SAB... AND UW-CIMSS ADT. IN ADDITION...A 14/0409Z ASCAT OVERPASS CAUGHT THE WEST SIDE OF THE CIRCULATION AND REVEALED SEVERAL 34-KT UNFLAGGED SURFACE WIND VECTORS. BASED ON THIS INFORMATION...THE DEPRESSION HAS BEEN UPGRADED TO TROPICAL STORM CARLOTTA. THE ESTIMATED CENTRAL PRESSURE IS BASED ON VALUABLE REPORTS FROM SHIP V7DI7 LOCATED JUST EAST OF THE CENTER OF CARLOTTA. THE INITIAL MOTION ESTIMATE IS 315/09 KT. CARLOTTA IS MOVING ON A STEADY NORTHWESTWARD TRACK AND THIS GENERAL MOTION IS EXPECTED TO CONTINUE FOR THE NEXT 48 HOURS OR SO AS THE CYCLONE MOVES AROUND THE WESTERN PERIPHERY OF A MID- TO UPPER-LEVEL RIDGE SITUATED OVER THE WESTERN CARIBBEAN SEA AND CENTRAL AMERICA. AFTER THAT... HOWEVER...THE GLOBAL AND REGIONAL MODELS ARE NOW FORECASTING A RIDGE TO DEVELOP TO THE NORTH OF THE CYCLONE FROM BAJA CALIFORNIA EASTWARD ACROSS NORTHERN MEXICO AND INTO TEXAS. THIS BLOCKING PATTERN IS EXPECTED TO FORCE CARLOTTA TO SLOW DOWN AND TURN WESTWARD AS IT NEARS THE SOUTH-CENTRAL COAST OF MEXICO BY 72 HOURS...AND POSSIBLY STALL IN THE GENERAL VICINITY OF ACAPULCO BY 96 HOURS BEFORE DRIFTING BACK SOUTHWARD OVER THE OCEAN. THE MODEL GUIDANCE HAS GENERALLY SHIFTED WESTWARD FROM THE PREVIOUS ADVISORY AFTER 48 HOURS...AND THE OFFICIAL FORECAST TRACK REFLECTS THIS NEW TREND AS WELL. AS A RESULT...96- AND 120-HOUR FORECAST POSITIONS HAVE BEEN ADDED TO THIS ADVISORY. THE OFFICIAL FORECAST TRACK IS ESSENTIALLY JUST AN UPDATE OF THE PREVIOUS ADVISORY THROUGH 48 HOURS...AND IS THEN WEST OF THE PREVIOUS TRACK AFTER THAT...AND CLOSELY FOLLOWS A BLEND OF THE ECMWF...GFS...UKMET...NOGAPS...AND HWRF MODELS. ENVIRONMENTAL AND OCEANIC CONDITIONS ARE FAVORABLE FOR CARLOTTA TO STRENGTHEN OVER THE NEXT 48 HOURS BEFORE THE CYCLONE BEGINS TO INTERACT WITH LAND. AS ALLUDED TO IN THE PREVIOUS DISCUSSION... RAPID INTENSIFICATION OF THE SMALL CYCLONE IS A VERY DISTINCT POSSIBILITY IF THE LOW-LEVEL CENTER DEVELOPS FARTHER INTO THE CONVECTIVE CLOUD MASS DURING THE NEXT 6 HOURS OR SO. ALTHOUGH THIS SCENARIO WAS CONSIDERED FOR THIS ADVISORY...THE NEW INTENSITY FORECAST IS ALREADY ABOUT 10 KT ABOVE THE PREVIOUS ADVISORY AND MOST OF THE INTENSITY GUIDANCE AS WELL THROUGH 48 HOURS...WHICH IS PLENTY ROBUST FOR ONLY A SECOND ADVISORY PACKAGE. HOWEVER...EVEN THE HWRF AND ECMWF MODELS MAKE CARLOTTA A HURRICANE BY 48 HOURS... WHICH ADDS SOME CREDENCE TO THE NEW HIGHER INTENSITY FORECAST. AT 72 HOURS AND BEYOND...THE INTENSITY FORECAST IS RATHER UNCERTAIN DUE TO HOW MUCH CARLOTTA WILL INTERACT WITH THE COASTAL SIERRA MADRE DEL SUR MOUNTAIN RANGE. IF CARLOTTA MOVES FARTHER INLAND THAN EXPECTED...THEN THE CYCLONE WILL WEAKEN MORE THAN FORECAST...AND VICE VERSA IF IT SHOULD INSTEAD REMAIN OFFSHORE. BASED ON THE NEW TRACK AND INTENSITY FORECASTS...HURRICANE AND TROPICAL STORM WARNINGS WILL LIKELY BE REQUIRED LATER THIS MORNING FOR PORTIONS OF THE CURRENT HURRICANE WATCH AREA. USERS ARE AGAIN REMINDED NOT TO FOCUS ON THE EXACT FORECAST TRACK AS TYPICAL NHC FORECAST ERRORS AT 48 AND 72 HOURS ARE 80 TO 110 N MI. FORECAST POSITIONS AND MAX WINDS INIT 14/0900Z 10.3N 93.3W 35 KT 40 MPH 12H 14/1800Z 11.4N 94.0W 45 KT 50 MPH 24H 15/0600Z 12.8N 95.1W 55 KT 65 MPH 36H 15/1800Z 14.3N 96.2W 65 KT 75 MPH 48H 16/0600Z 15.5N 97.2W 70 KT 80 MPH 72H 17/0600Z 16.6N 99.0W 55 KT 65 MPH...INLAND 96H 18/0600Z 16.8N 100.0W 50 KT 60 MPH...INLAND 120H 19/0600Z 16.3N 100.0W 45 KT 50 MPH...OVER WATER $$ FORECASTER STEWART