000
WTNT44 KNHC 111500
TCDAT4
 
TROPICAL STORM MARIA DISCUSSION NUMBER  20
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142011
1100 AM AST SUN SEP 11 2011
 
THE SATELLITE APPEARANCE OF MARIA IS RATHER DECEIVING THIS MORNING.
ALTHOUGH THE TROPICAL STORM IS PRODUCING A LARGE AREA OF VERY DEEP
CONVECTION...THE LOW-LEVEL CENTER IS LOCATED WELL TO THE SOUTHWEST
OF THE CONVECTION DUE TO STRONG SOUTHWESTERLY SHEAR FROM A
MID/UPPER-LEVEL TROUGH TO THE NORTHWEST OF MARIA. VISIBLE SATELLITE
IMAGERY...SURFACE OBSERVATIONS...AND AIRCRAFT DATA INDICATE THAT
THE CENTER IS LOCATED JUST NORTH OF THE VIRGIN ISLANDS. THE
AIRCRAFT HAS YET TO SAMPLE THE NORTHEASTERN PORTION OF THE
CIRCULATION...SO THE INITIAL INTENSITY IS HELD AT 50 KT...WHICH
IS CLOSE TO THE LATEST DVORAK ESTIMATES.
 
THE AFOREMENTIONED MID/UPPER-LEVEL TROUGH IS FORECAST TO GRADUALLY
WEAKEN...BUT MOST OF THE MODEL GUIDANCE KEEPS THE CYCLONE IN AN
AREA OF MODERATE SOUTHWESTERLY UPPER-LEVEL WINDS DURING THE NEXT
FEW DAYS.  FOR NOW...THE OFFICIAL FORECAST IS UNCHANGED FROM THE
PREVIOUS ADVISORY AND FOLLOWS THE MORE CONSERVATIVE LGEM MODEL.
 
MARIA HAS BEEN MOVING NEARLY DUE WESTWARD THIS MORNING...HOWEVER THE
LONGER TERM MOTION IS WEST-NORTHWESTWARD AT ABOUT 8 KT.  MARIA IS
FORECAST TO CONTINUE ON A MOTION BETWEEN WEST-NORTHWEST AND
NORTHWEST TO THE SOUTH OF THE SUBTROPICAL RIDGE FOR THE NEXT 24 TO
36 HOURS.  HOWEVER...GIVEN THE CURRENT DISORGANIZED STRUCTURE OF
THE CYCLONE...A MORE WESTWARD TRACK IS POSSIBLE. THE OFFICIAL
FORECAST HAS BEEN SHIFTED TO THE SOUTH DURING THE NEXT FIRST COUPLE
OF DAYS AND AN ADDITIONAL SOUTHWARD ADJUSTMENT COULD BE REQUIRED. 
AFTER 48 HOURS...MARIA IS EXPECTED TO TURN NORTHWARD AHEAD OF A
MID-LATITUDE TROUGH APPROACHING THE EAST COAST OF THE UNITED
STATES.  THE LATTER PORTION OF THE FORECAST TRACK IS SIMILAR TO THE
PREVIOUS ADVISORY AND NEAR THE MIDDLE OF THE GUIDANCE ENVELOPE.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  11/1500Z 19.0N  64.6W   50 KT  60 MPH
 12H  12/0000Z 20.1N  65.6W   50 KT  60 MPH
 24H  12/1200Z 21.1N  66.9W   50 KT  60 MPH
 36H  13/0000Z 21.9N  68.0W   55 KT  65 MPH
 48H  13/1200Z 22.9N  69.1W   60 KT  70 MPH
 72H  14/1200Z 27.5N  69.7W   65 KT  75 MPH
 96H  15/1200Z 34.5N  67.0W   65 KT  75 MPH
120H  16/1200Z 45.0N  57.0W   60 KT  70 MPH
 
$$
FORECASTER BROWN