[Tropical] Tropical Cyclone Discussion

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WTNT42 KNHC 150232
TCDAT2

TROPICAL STORM GERT DISCUSSION NUMBER   5
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072011
1100 PM AST SUN AUG 14 2011

ON SATELLITE IMAGERY...GERT IS CHARACTERIZED BY A FAIRLY CIRCULAR
AREA OF DEEP CONVECTION BUT IS LACKING IN BANDING FEATURES.  A
SMALL UPPER-LEVEL ANTICYCLONE THAT FORMED OVER THE STORM IS
PROVIDING SOME MODEST OUTFLOW...PARTICULARLY OVER THE SOUTHERN
SEMICIRCLE OF THE CIRCULATION.  BASED ON THE AIRCRAFT OBSERVATIONS
FROM A FEW HOURS AGO...THE MAXIMUM WINDS ARE ESTIMATED TO BE 40
KT...WHICH IS A LITTLE ABOVE THE LATEST DVORAK INTENSITY ESTIMATES.
GERT IS LIKELY TO REMAIN OVER WARM WATERS AND IN A WEAK SHEAR
ENVIRONMENT FOR ANOTHER DAY OR SO...WHICH SHOULD ALLOW FOR SOME
INTENSIFICATION.  BY AROUND 48 HOURS...GLOBAL MODELS INDICATE AN
ABRUPT INCREASE IN VERTICAL SHEAR AS GERT APPROACHES A BELT OF
STRONG UPPER-LEVEL WESTERLIES.  THE OFFICIAL INTENSITY FORECAST IS
SLIGHTLY BELOW THE MODEL CONSENSUS.  IN 72 HOURS...PERHAPS
SOONER...GERT IS LIKELY TO BECOME EMBEDDED IN A FRONTAL ZONE AND
TRANSFORMED INTO AN EXTRATROPICAL CYCLONE.  BEYOND THAT TIME...THE
SYSTEM IS EXPECTED TO BECOME ABSORBED BY A LARGE HIGH-LATITUDE LOW
PRESSURE SYSTEM.

LATEST SATELLITE IMAGES INDICATE THAT THE FORWARD SPEED IS
INCREASING AND THE MOTION IS ESTIMATED TO BE AROUND 345/10.  GERT
IS MOVING BETWEEN A RATHER DEEP MID-LEVEL TROUGH THAT IS NEARING
THE U.S. EAST COAST AND A SUBTROPICAL HIGH OVER THE CENTRAL
ATLANTIC.  THE TRACK MODEL GUIDANCE IS IN GOOD AGREEMENT ON A
GRADUAL TURN TOWARD THE NORTH...THEN NORTH-NORTHEAST AND EVENTUALLY
NORTHEAST WITH INCREASING FORWARD SPEED OVER THE NEXT FEW DAYS.
THE CURRENT OFFICIAL FORECAST IS A LITTLE SLOWER THAN THE LATEST
MULTI-MODEL CONSENSUS AND SLIGHTLY FASTER THAN THE PREVIOUS NHC
FORECAST.

INTERESTS IN BERMUDA ARE REMINDED NOT TO FOCUS ON THE EXACT FORECAST
TRACK OF GERT AS ONLY A SLIGHT DEVIATION TO THE LEFT DURING THE
NEXT 12 HOURS COULD BRING STRONG WINDS CLOSE TO...OR OVER...THE
ISLAND.

FORECAST POSITIONS AND MAX WINDS

INIT  15/0300Z 30.2N  63.3W   40 KT  45 MPH
 12H  15/1200Z 31.9N  63.4W   45 KT  50 MPH
 24H  16/0000Z 34.7N  62.2W   50 KT  60 MPH
 36H  16/1200Z 38.5N  59.5W   55 KT  65 MPH
 48H  17/0000Z 42.0N  55.0W   50 KT  60 MPH
 72H  18/0000Z 47.0N  40.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 96H  19/0000Z...DISSIPATED

$$
FORECASTER PASCH


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