Tropical Storm MARIA

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TROPICAL STORM MARIA DISCUSSION NUMBER  25
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142011
500 PM AST MON SEP 12 2011
 
MARIA HAS BEEN NEARLY STATIONARY FOR MUCH OF THE DAY...HOWEVER A
SLOW NORTHWARD OR NORTHWESTWARD MOTION HAS BEEN APPARENT VERY
RECENTLY.  THE LOW-LEVEL CENTER REMAINS NEAR THE WESTERN EDGE OF
A BURST OF NEW CONVECTION THAT HAS DEVELOPED THIS AFTERNOON.  NOAA
BUOY 41043...LOCATED ABOUT 125 N MI EAST OF THE CENTER...RECENTLY
REPORTED A 1-MINUTE SUSTAINED WIND OF 39 KT WITH A GUST TO 45 KT.
THIS OBSERVATION ALONG WITH THE 1800 UTC DVORAK ESTIMATES SUPPORT
MAINTAINING AN INITIAL INTENSITY OF 45 KT. STRONG SHEAR FROM AN
UPPER-LEVEL LOW AND TROUGH TO THE NORTH AND NORTHWEST OF MARIA IS
EXPECTED TO CONTINUE DURING THE NEXT DAY OR SO.  AFTER THAT...
SOUTHWESTERLY UPPER-LEVEL FLOW AHEAD OF A LARGE MID-LATITUDE
TROUGH MOVING OFF THE SOUTHEAST UNITED STATES IS EXPECTED TO
MAINTAIN MODERATE TO STRONG SHEAR OVER THE SYSTEM.  THE NHC
INTENSITY FORECAST CALLS FOR LITTLE SIGNIFICANT CHANGE IN STRENGTH
DURING THE FORECAST PERIOD...WHICH IS CONSISTENT WITH THE LGEM
MODEL.
 
ALTHOUGH MARIA HAS MOVED VERY LITTLE TODAY...THE MODEL GUIDANCE
INSISTS THAT THE CYCLONE WILL BEGIN MOVING SLOWLY NORTHWESTWARD
AROUND THE WESTERN SIDE OF A LOW- TO MID-LEVEL RIDGE OVER THE
CENTRAL ATLANTIC.  MARIA SHOULD TURN NORTHWARD THEN NORTHEASTWARD
AS IT RECURVES AHEAD OF A MID-LATITUDE TROUGH AND FRONT MOVING OFF
THE EAST COAST OF THE UNITED STATES DURING THE NEXT FEW DAYS. THE
TRACK GUIDANCE IS IN RELATIVELY GOOD AGREEMENT BUT SHOWS A SLOWER
MOTION THAN IN PREVIOUS RUNS. THE OFFICIAL TRACK IS SLIGHTLY EAST
OF THE PREVIOUS ADVISORY AND NOT AS FAST.
 
THE TROPICAL STORM FORCE WIND RADIUS OVER THE SOUTHEASTERN QUADRANT
HAS BEEN EXPANDED BASED ON 1324 UTC ASCAT DATA THAT SHOWED A SMALL
AREA OF 30-35 KT WINDS WELL EAST-SOUTHEAST OF THE CENTER.  IT IS
WORTH REMEMBERING THAT NHC RADII ESTIMATES REPRESENT THE MAXIMUM
EXTENT OF A PARTICULAR WIND THRESHOLD ANYWHERE WITHIN A QUADRANT.
IN THIS CASE...THE INITIAL WIND FIELD GRAPHIC IS LIKELY TO DEPICT
TROPICAL STORM FORCE WINDS NEAR OR OVER THE NORTHERN CARIBBEAN
ISLANDS WHEN IT REALITY THEY ARE OCCURRING ONLY OVER WATER IN A
SMALL AREA WELL TO EAST-SOUTHEAST OF THE CENTER.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  12/2100Z 21.0N  67.5W   45 KT  50 MPH
 12H  13/0600Z 21.6N  68.0W   45 KT  50 MPH
 24H  13/1800Z 22.8N  68.6W   50 KT  60 MPH
 36H  14/0600Z 24.8N  69.2W   50 KT  60 MPH
 48H  14/1800Z 27.5N  69.2W   50 KT  60 MPH
 72H  15/1800Z 34.5N  67.0W   50 KT  60 MPH
 96H  16/1800Z 45.0N  55.0W   50 KT  60 MPH...POST-TROP/EXTRATROP
120H  17/1800Z...DISSIPATED
 
$$
FORECASTER BROWN
 
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