000
WTNT44 KNHC 121441
TCDAT4
 
TROPICAL STORM MARIA DISCUSSION NUMBER  24
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142011
1100 AM AST MON SEP 12 2011
 
MARIA CONSISTS OF AN EXPOSED LOW-LEVEL CLOUD SWIRL DISPLACED ABOUT A
DEGREE TO THE WEST OF THE DEEP CONVECTION. GIVEN THIS LACK OF
ORGANIZATION...DVORAK NUMBERS FROM TAFB AND SAB HAVE BEGUN TO
DECREASE AND A BLEND OF THESE YIELDS 45 KT FOR THE INITIAL
INTENSITY. THE SHIPS MODEL INDICATES ABOUT 25 KT OF
WEST-NORTHWESTERLY SHEAR OVER MARIA...DUE TO THE PRESENCE OF AN
UPPER-LEVEL LOW LOCATED NEAR 25N 65W. THE GLOBAL MODELS DO NOT
WEAKEN THIS LOW UNTIL AFTER 24 HOURS...SO LITTLE INTENSIFICATION
SEEMS LIKELY UNTIL AFTER THAT TIME. EVEN AFTER THE UPPER-LEVEL LOW
WEAKENS...MARIA WILL STILL ENCOUNTER 15 TO 20 KT OF WESTERLY OR
SOUTHWESTERLY SHEAR AHEAD OF THE DEEP-LAYER TROUGH MOVING OFF THE
EAST COAST OF THE UNITED STATES. THEREFORE THE NEW OFFICIAL
FORECASTS ONLY SHOWS SLIGHT STRENGTHENING AT 36 HOURS AND NONE
AFTER THAT TIME. THIS FORECAST IS CLOSE TO THE SHIPS MODEL THROUGH
48 HOURS AND THE LGEM BEYOND THAT TIME UNTIL EXTRATROPICAL
TRANSITION. 

THE LOW-LEVEL CENTER HAS BEEN MOVING ONLY SLOWLY WESTWARD AT AROUND
2 KT FOR THE PAST FEW HOURS...SLOWER AND WELL TO THE LEFT OF THE
PREVIOUS TRACK. DUE TO THE MORE WESTWARD AND SLOWER INITIAL
MOTION...THE NEW NHC TRACK FORECAST HAS BEEN ADJUSTED ABOUT A
DEGREE TO THE LEFT OF AND IS SLOWER THAN THE PREVIOUS PACKAGE
THROUGH 48 HOURS. THROUGH 24 HOURS THE NHC FORECAST IS ALSO LEFT OF
MOST OF THE GUIDANCE SINCE NEARLY ALL OF THE MODELS TAKE MARIA
IMMEDIATELY NORTHWESTWARD. AFTER 48 HOURS THE NHC FORECAST IS
LARGELY AN EXTENSION OF THE PREVIOUS ONE AND IS ADJUSTED TOWARD THE
NEW MULTI-MODEL CONSENSUS AND GUIDANCE FROM THE OCEAN PREDICTION
CENTER AT DAYS 4 AND 5. IT SHOULD BE NOTED THAT THIS FORECAST
ASSUMES MARIA WILL REMAIN A DEEP CYCLONE AND FEEL THE INFLUENCE OF
THE DEEP-LAYER TROUGH MOVING OFF THE EAST COAST OF NORTH AMERICA.
IF MARIA BECOMES A SHALLOW SYSTEM COMPLETELY DEVOID OF DEEP
CONVECTION...IT COULD MOVE MORE WESTWARD THAN INDICATED HERE AND
WEAKEN OR PERHAPS EVEN DISSIPATE AS A TROPICAL CYCLONE WITHIN THE
NEXT DAY OR TWO. 

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  12/1500Z 20.7N  67.3W   45 KT  50 MPH
 12H  13/0000Z 21.1N  68.1W   45 KT  50 MPH
 24H  13/1200Z 22.6N  69.2W   45 KT  50 MPH
 36H  14/0000Z 24.5N  69.7W   50 KT  60 MPH
 48H  14/1200Z 26.5N  69.9W   50 KT  60 MPH
 72H  15/1200Z 34.0N  67.0W   50 KT  60 MPH
 96H  16/1200Z 43.5N  57.5W   50 KT  60 MPH...POST-TROP/EXTRATROP
120H  17/1200Z 54.0N  39.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
 
$$
FORECASTER BRENNAN