000 WTPZ43 KNHC 142033 TCDEP3 TROPICAL STORM CARLOTTA DISCUSSION NUMBER 4 NWS NATIONAL HURRICANE CENTER MIAMI FL EP032012 200 PM PDT THU JUN 14 2012 CARLOTTA HAS DEVELOPED A RAGGED CENTRAL DENSE OVERCAST THAT CONTINUES TO BE SURROUNDED BY A COMPLEX OF OUTER RAIN BANDS. HOWEVER...A JUST-RECEIVED AMSU OVERPASS DOES NOT YET SHOW AN EYEWALL FORMING UNDER THE OVERCAST. SATELLITE INTENSITY ESTIMATES ARE 45 KT FROM TAFB AND SAB...AND THAT IS THE INITIAL INTENSITY FOR THIS ADVISORY. THE CIRRUS OUTFLOW IS GOOD IN ALL QUADRANTS EXCEPT THE EAST. THE INITIAL MOTION IS 330/9...A LITTLE TO THE RIGHT OF THE PREVIOUS MOTION. CARLOTTA IS CURRENTLY BEING STEERED BY A MID/UPPER-LEVEL RIDGE OVER THE WESTERN CARIBBEAN AND A SMALL UPPER-LEVEL TROUGH SEEN IN WATER VAPOR IMAGERY TO THE WEST OF THE CYCLONE. THE DYNAMICAL MODELS FORECAST THIS PATTERN TO PERSIST FOR PERHAPS 36-48 HR...FOLLOWED BY A MID/UPPER-LEVEL RIDGE BUILDING OVER NORTHERN MEXICO. THIS EVOLUTION SHOULD CAUSE CARLOTTA TO MOVE GENERALLY NORTHWESTWARD FOR ABOUT 36 HR...FOLLOWED BY A MORE WESTWARD MOTION FROM 36-72 HR. THE ENVELOPE OF TRACK MODEL GUIDANCE HAS CHANGED LITTLE DURING THE LAST 6 HR...AND IT REMAINS IN FAIR AGREEMENT THAT CARLOTTA SHOULD TRACK NEAR OR OVER THE COAST OF MEXICO FROM 36-72 HR. THE NEW FORECAST TRACK IS JUST A LITTLE NORTH OF THE PREVIOUS FORECAST BASED ON THE INITIAL LOCATION AND MOTION. AT ABOUT 72 HR...THE MEXICAN RIDGE IS FORECAST TO WEAKEN AS A MID/UPPER-LEVEL TROUGH DEVELOPS OVER THE GULF OF MEXICO. THIS SHOULD LEAVE THE CYCLONE IN AN AREA OF WEAK STEERING CURRENTS... WHICH IS REFLECTED IN A SLOW SOUTHEASTWARD DRIFT IN THE TRACK FORECAST. CARLOTTA REMAINS IN AN ENVIRONMENT OF LIGHT VERTICAL WIND SHEAR AND OVER 30C SEA SURFACE TEMPERATURES THAT SHOULD ALLOW AT LEAST STEADY STRENGTHENING THROUGH 36 HR. THE RAPID INTENSIFICATION INDEX OF THE SHIPS MODEL SHOWS A 60-70 PERCENT CHANCE OF 25-KT STRENGTHENING DURING THE NEXT 24 HR...AND ABOUT A 35 PERCENT CHANCE OF 40-KT STRENGTHENING. THE INTENSITY FORECAST NOW CALLS FOR CARLOTTA TO BECOME A HURRICANE IN LESS THAN 24 HR AND REACH A PEAK INTENSITY OF 80 KT IN 36 HR...AND THIS PEAK COULD BE CONSERVATIVE. AFTER 36 HR...LAND INTERACTION WILL BE THE MAIN CONTROLLING FACTOR ON THE INTENSITY. IF CARLOTTA MOVES INLAND...IT SHOULD DISSIPATE OVER THE MOUNTAINS OF MEXICO. EVEN IF IT STAYS OFFSHORE...IT IS EXPECTED TO BE CLOSE ENOUGH TO INTERACT WITH THE MOUNTAINS AND WEAKEN AS SHOWN BY THE GFDL/HWRF MODELS...AND THAT SCENARIO IS USED IN THE INTENSITY FORECAST. USERS ARE AGAIN REMINDED NOT TO FOCUS ON THE EXACT FORECAST TRACK...AS ANY DEVIATION TO THE NORTH AND EAST OF THE FORECAST TRACK WOULD BRING THE CENTER OF CARLOTTA ONTO THE COAST OF MEXICO. FORECAST POSITIONS AND MAX WINDS INIT 14/2100Z 11.8N 94.2W 45 KT 50 MPH 12H 15/0600Z 12.9N 95.0W 55 KT 65 MPH 24H 15/1800Z 14.2N 96.2W 70 KT 80 MPH 36H 16/0600Z 15.3N 97.3W 80 KT 90 MPH...NEAR COAST 48H 16/1800Z 16.1N 98.4W 80 KT 90 MPH...NEAR COAST 72H 17/1800Z 16.5N 100.0W 60 KT 70 MPH...NEAR COAST 96H 18/1800Z 16.0N 100.0W 45 KT 50 MPH 120H 19/1800Z 15.5N 99.5W 45 KT 50 MPH $$ FORECASTER BEVEN