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Tropical Depression SEVEN (Text)

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TROPICAL DEPRESSION SEVEN DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072012
1100 PM AST THU AUG 09 2012

A SMALL AREA OF CONVECTION HAS PERSISTED NEAR THE CENTER OF THE
DEPRESSION DURING THE PAST SEVERAL HOURS...ALTHOUGH THERE ARE NO
BANDING FEATURES APPARENT.  WITH NO SIGNIFICANT CHANGES IN THE
SATELLITE INTENSITY ESTIMATES...THE INITIAL INTENSITY WILL REMAIN
30 KT.  THE CENTER OF THE CYCLONE SHOULD MOVE CLOSE TO NOAA BUOY
41041 OVERNIGHT...WHICH SHOULD PROVIDE A BETTER LOOK AT THE
INTENSITY.  ALTHOUGH THE WIND SHEAR IS LIGHT FOR NOW...THE
ENVIRONMENT AROUND THE DEPRESSION ALWAYS SEEMS TO HAVE SOME
NEGATIVE FACTORS THROUGHOUT THE FORECAST PERIOD.  THERE IS PLENTY
OF DRY AIR AND MARGINAL THERMODYNAMICS NEAR THE CIRCULATION
INITIALLY...WHICH IS PROBABLY RESPONSIBLE FOR THE LACKLUSTER
CONVECTION.  AS THE SYSTEM MOVES WESTWARD OVER WARMER WATERS...THE
INSTABILITY SHOULD RISE...BUT THE SHEAR SHOULD ALSO INCREASE
WITHIN 24 TO 36 HOURS DUE TO A LARGE MID-OCEANIC TROUGH.  THIS
SHEAR IS LIKELY TO FURTHER INCREASE AS THE CYCLONE APPROACHES THE
TROUGH.  THE OFFICIAL FORECAST CONTINUES THE TREND OF THE PREVIOUS
FORECAST...SHOWING ONLY GRADUAL INTENSIFICATION THROUGH 48 HOURS. 
THE DAY 4 AND 5 PREDICTIONS HAVE BEEN REDUCED GIVEN THE LIKELY
PERSISTENCE OF THE SHEAR AND THE CLIMATOLOGICAL NON-DEVELOPMENT
TREND IN THE CENTRAL CARIBBEAN SEA.

THE INITIAL MOTION CONTINUES AT 270/17.  THIS GENERAL TRACK AND
SPEED IS LIKELY FOR THE NEXT COUPLE OF DAYS AS A MID-LEVEL RIDGE
PERSISTS NORTH OF THE DEPRESSION.  AFTER THAT TIME...THERE ARE
INDICATIONS FROM THE GLOBAL MODELS THAT THE RIDGE COULD WEAKEN
SOMEWHAT...AND THERE HAS BEEN A SUBTLE SHIFT TO A MORE WEST-
NORTHWEST COURSE IN MOST OF THE GUIDANCE BEYOND 36 HOURS.  THE
NEW FORECAST...HOWEVER...STAYS ON THE SOUTHWEST SIDE OF THE
GUIDANCE ENVELOPE AND IS JUST A BIT NORTH OF THE PREVIOUS ONE...
SINCE THE MODELS HAVE BEEN KNOWN TO HAVE A SLOW AND POLEWARD BIAS
WITH LOW-LATITUDE SYSTEMS IN THIS AREA.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  10/0300Z 13.7N  45.5W   30 KT  35 MPH
 12H  10/1200Z 13.6N  48.1W   35 KT  40 MPH
 24H  11/0000Z 13.6N  51.7W   35 KT  40 MPH
 36H  11/1200Z 13.7N  55.3W   40 KT  45 MPH
 48H  12/0000Z 14.1N  58.8W   45 KT  50 MPH
 72H  13/0000Z 14.9N  65.5W   45 KT  50 MPH
 96H  14/0000Z 16.0N  71.5W   45 KT  50 MPH
120H  15/0000Z 17.0N  78.0W   45 KT  50 MPH
 
$$
FORECASTER BLAKE
 
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