Tropical Depression FOUR-E

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TROPICAL DEPRESSION FOUR-E DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP042012
800 AM PDT WED JUL 04 2012
 
THE DEPRESSION HAS CHANGED LITTLE SINCE THE PREVIOUS ADVISORY AS THE 
CONVECTION REMAINS POORLY ORGANIZED AND SHEARED TO THE SOUTH OF THE
LOW-LEVEL CENTER. NIGHTTIME VISIBLE AND FIRST DAYLIGHT VISIBLE
IMAGERY INDICATE A FEW SMALL SWIRLS HAVE POPPED OUT THE NORTH SIDE
OF THE MAIN CONVECTIVE CLOUD MASS...WHICH HAS MADE LOCATING THE
CENTER SOMEWHAT DIFFICULT THIS MORNING. THE CENTER OF THE
DEPRESSION IS ASSUMED TO BE SOUTH OF THE AFOREMENTIONED LOW-LEVEL
SWIRLS AND JUST INSIDE THE NORTHERN EDGE OF THE CIRRUS CLOUD
SHIELD...WHICH IS CLOSE TO THE PREVIOUS FORECAST TRACK. ALTHOUGH
SATELLITE INTENSITY ESTIMATES ARE A CONSENSUS T2.5/35 KT FROM TAFB
AND SAB...THE INITIAL INTENSITY IS BEING MAINTAINED AT 30 KT BASED
ON THE RAGGED APPEARANCE OF THE OVERALL CLOUD SIGNATURE...PLUS A
T2.0/30 KT UW-CIMSS ADT INTENSITY ESTIMATE.
 
THE INITIAL MOTION ESTIMATE IS 300/13 KT...BASED ON CONTINUITY WITH
THE PREVIOUS FORECAST TRACK AND RECENT MICROWAVE IMAGERY. THE NHC
MODEL GUIDANCE IS IN EXCELLENT AGREEMENT ON THE CYCLONE MOVING
WEST-NORTHWESTWARD FOR THE NEXT DAY OR TWO. AFTER THAT...THE SYSTEM
IS EXPECTED TO TURN WESTWARD AS IT ENCOUNTERS THE DEEPER EASTWARD
STEERING FLOW OF THE STRONG SUBTROPICAL RIDGE SITUATED TO ITS
NORTH. THE OFFICIAL FORECAST TRACK IS LOCATED ALONG THE SOUTHERN
EDGE OF THE TIGHTLY PACKED MODEL GUIDANCE SUITE AND LIES CLOSE TO
THE CONSENSUS MODEL...TVCN.
 
THE CYCLONE IS FORECAST TO REMAIN UNDER THE INFLUENCE OF MODERATE
NORTHERLY TO NORTHEASTERLY VERTICAL WIND SHEAR FOR THE NEXT 24
HOURS...WHICH SHOULD ONLY ALLOW FOR GRADUAL INTENSIFICATION. AFTER
THAT...HOWEVER...THE GLOBAL MODELS ARE FORECASTING THE SHEAR TO
WEAKEN CONSIDERABLY...WHICH SHOULD ALLOW FOR MORE SIGNIFICANT
STRENGTHENING TO OCCUR. IN FACT...THE GFS...ECWMF...AND HWRF MODELS
DEVELOP A RATHER ROBUST TROPICAL CYCLONE THROUGH THE 200 MB LEVEL
BY 72 HOURS...AND THE OFFICIAL FORECAST SHOWS THE DEPRESSION
STRENGTHENING INTO A HURRICANE AT THAT TIME BASED UPON THESE MODEL
DEPICTIONS. AFTER THAT...HOWEVER...THE CYCLONE IS EXPECTED TO BE
MOVING OVER SUB-25C SSTS...WHICH SHOULD INDUCE GRADUAL WEAKENING
DESPITE RELATIVELY LOW WIND SHEAR CONDITIONS. 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  04/1500Z 13.1N 107.1W   30 KT  35 MPH
 12H  05/0000Z 13.8N 108.4W   35 KT  40 MPH
 24H  05/1200Z 14.4N 110.5W   40 KT  45 MPH
 36H  06/0000Z 14.9N 112.4W   45 KT  50 MPH
 48H  06/1200Z 15.0N 114.6W   50 KT  60 MPH
 72H  07/1200Z 15.1N 118.6W   65 KT  75 MPH
 96H  08/1200Z 15.2N 122.6W   60 KT  70 MPH
120H  09/1200Z 15.9N 127.4W   50 KT  60 MPH
 
$$
FORECASTER STEWART
 
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