[Tropical] Tropical Cyclone Discussion

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WTNT44 KNHC 211450
TCDAT4

TROPICAL DEPRESSION NINE DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL092012
1100 AM AST TUE AUG 21 2012

A BURST OF CONVECTION CONTINUES JUST SOUTH OR SOUTHWEST OF THE
CENTER OF TROPICAL DEPRESSION NINE...ALTHOUGH THE OVERALL COVERAGE
HAS DECREASED DURING THE PAST FEW HOURS.  SATELLITE INTENSITY
ESTIMATES ARE 35 KT FROM TAFB AND 30 KT FROM SAB.  BASED ON THESE
DATA AND THE RELATIVELY HIGH PRESSURE OF 1010 MB AT NOAA BUOY
41040...THE INITIAL INTENSITY REMAINS 30 KT.  AN AIR FORCE RESERVE
HURRICANE HUNTER AIRCRAFT IS SCHEDULED TO INVESTIGATE THE
DEPRESSION THIS AFTERNOON.

THE INITIAL MOTION REMAINS 270/17.  THE DEPRESSION IS LOCATED SOUTH
OF A DEEP-LAYER SUBTROPICAL RIDGE THAT IS FORECAST TO REMAIN INTACT
FOR THE NEXT 72 HR...WHICH SHOULD KEEP THE CYCLONE MOVING GENERALLY
WESTWARD AS SHOWN BY THE TIGHTLY CLUSTERED TRACK MODEL GUIDANCE.
AFTER THAT...THE GLOBAL MODELS ARE FORECASTING A SHORTWAVE TROUGH
TO DIG SOUTHWARD OVER THE SOUTHEASTERN U.S. AND THE GULF OF
MEXICO...WHICH IS EXPECTED TO WEAKEN THE RIDGE ACROSS FLORIDA AND
THE BAHAMAS. THIS SHOULD ALLOW THE CYCLONE TO TURN WEST-
NORTHWESTWARD AND SLOW DOWN ACROSS THE NORTH-CENTRAL CARIBBEAN SEA.
THE GUIDANCE SHOWS MORE SPREAD DURING THIS PERIOD...WITH THE UKMET
ON THE RIGHT EDGE SHOWING THE CYCLONE MOVING ALONG THE NORTHERN
COAST OF HISPANIOLA...AND THE ECMWF AND GFS ON THE LEFT EDGE
SHOWING THE SYSTEM PASSING SOUTH OF HISPANIOLA.  THE NEW FORECAST
TRACK IS SIMILAR TO THE PREVIOUS TRACK THROUGH 72 HR...THEN IS A
LITTLE TO THE RIGHT OF THE PREVIOUS TRACK AFTER THAT.  THE TRACK IS
IN BEST AGREEMENT WITH A BLEND OF THE GFS AND ECMWF MODELS.

THE DEPRESSION IS CURRENTLY EXPERIENCING LIGHT/MODERATE
NORTHEASTERLY VERTICAL WIND SHEAR.  THIS SHOULD DIMINISH DURING THE
NEXT 24 HR OR SO...LEAVING THE CYCLONE IN A FAVORABLE ENVIRONMENT
FOR DEVELOPMENT.  THE NEW INTENSITY FORECAST IS THE SAME AS THE
PREVIOUS FORECAST THROUGH 72 HR...SHOWING THE SYSTEM BECOMING A
TROPICAL STORM IN 12 HR AND A HURRICANE IN 48 HR.  AFTER 72
HR...THE FORECAST TRACK BRINGS THE SYSTEM CLOSER TO HISPANIOLA AND
CUBA THAN THE PREVIOUS TRACK.  BASED ON THIS...THE INTENSITY
FORECAST DURING THAT TIME HAS BEEN LOWERED BY 5-10 KT.


FORECAST POSITIONS AND MAX WINDS

INIT  21/1500Z 15.1N  52.8W   30 KT  35 MPH
 12H  22/0000Z 15.2N  55.3W   35 KT  40 MPH
 24H  22/1200Z 15.5N  58.4W   40 KT  45 MPH
 36H  23/0000Z 15.9N  61.5W   50 KT  60 MPH
 48H  23/1200Z 16.2N  64.6W   65 KT  75 MPH
 72H  24/1200Z 17.0N  70.0W   80 KT  90 MPH
 96H  25/1200Z 18.5N  74.0W   90 KT 105 MPH...INLAND
120H  26/1200Z 20.5N  77.5W   85 KT 100 MPH...OVER WATER

$$
FORECASTER BEVEN



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