[Tropical] Tropical Cyclone Discussion

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WTNT44 KNHC 072040
TCDAT4

TROPICAL STORM MARIA DISCUSSION NUMBER   5
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142011
500 PM AST WED SEP 07 2011

THE OVERALL CLOUD PATTERN IS APPARENTLY WELL ORGANIZED ON VISIBLE
IMAGES...BUT NOT REALLY. THE LOW-LEVEL CENTER IS LOCATED ON THE
SOUTHWEST EDGE OF THE CONVECTION AND MOST OF THE ORGANIZED
RAINBANDS ARE SHIFTING TO THE NORTHEASTERN PORTION OF THE CYCLONE.
THIS WAS CONFIRMED BY RECENT MICROWAVE IMAGES. THE OUTFLOW IS
BECOMING DISRUPTED DUE A DEVELOPING WIND SHEAR AS FORECAST BY
GLOBAL MODELS AND THE SHIPS GUIDANCE. THE SHEAR IS INCREASING...BUT
IS NOT EXPECTED TO BE COMPLETELY HOSTILE TO THE CYCLONE. THE SHEAR
IN COMBINATION WITH THE RAPID FORWARD SPEED SUPPORT KEEPING MARIA
WITH LITTLE CHANGE IN INTENSITY THROUGH FIVE DAYS AS SUGGESTED BY
THE LGEM. ONLY THE GFDL MODEL INSISTS ON INTENSIFICATION. THE
CYCLONE IS APPROACHING NOAA BUOY 41041...SO WE WILL LIKELY KNOW
MORE ABOUT THE STRUCTURE OF MARIA LATER TONIGHT.

THE AVERAGE MOTION HAS BEEN TOWARD THE WEST OR 275 DEGREES AT 20
KNOTS. FOR THE NEXT 24 TO 36 HOURS...ALL MODELS ARE IN EXCELLENT
AGREEMENT FORECASTING MARIA TOWARD THE WEST OR WEST-NORTHWEST AT A
RAPID PACE. THEREAFTER...IT IS DEJA VU ALL OVER AGAIN WITH THE
TROUGH ALONG THE EAST COAST OF THE UNITED STATES AND THE
SUBTROPICAL RIDGE TO THE NORTH OF THE CYCLONE. THIS HAS BEEN THE
SCENARIO OBSERVED DURING THE TWO OR THREE PREVIOUS RECURVING
CYCLONES THIS SEASON. GIVEN THIS PATTERN...SOME MODELS LIKE THE GFS
AND HWRF TURN THE CYCLONE NORTHWESTWARD AND NORTHWARD AND THE ECMWF
AND UK PROLONGING THE EVENTUAL NORTHWARD TURN A LITTLE LONGER.  THE
OFFICIAL FORECAST IS...AS USUAL...A BLEND OF THESE GUIDANCE.


FORECAST POSITIONS AND MAX WINDS

INIT  07/2100Z 13.2N  44.2W   45 KT  50 MPH
 12H  08/0600Z 13.6N  47.1W   45 KT  50 MPH
 24H  08/1800Z 14.5N  51.5W   45 KT  50 MPH
 36H  09/0600Z 15.0N  55.0W   45 KT  50 MPH
 48H  09/1800Z 16.0N  58.5W   45 KT  50 MPH
 72H  10/1800Z 18.5N  63.5W   45 KT  50 MPH
 96H  11/1800Z 22.0N  68.0W   45 KT  50 MPH
120H  12/1800Z 25.0N  70.0W   45 KT  50 MPH

$$
FORECASTER AVILA


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