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Tropical Depression FOUR-E


ZCZC MIATCDEP4 ALL
TTAA00 KNHC DDHHMM
 
TROPICAL DEPRESSION FOUR-E DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP042011
800 AM PDT MON JUL 18 2011
 
SATELLITE IMAGERY INDICATES THUNDERSTORM ACTIVITY HAS BECOME
SUFFICIENTLY ORGANIZED NEAR THE CENTER OF THE WELL-DEFINED LOW
PRESSURE AREA LOCATED TO THE SOUTH OF GUATEMALA FOR THIS SYSTEM TO
BE DESIGNATED AS THE FOURTH TROPICAL DEPRESSION OF THE SEASON.
ALTHOUGH SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB ARE ONLY
T1.5/25 KT...NHC ADT ESTIMATES INDICATE THE SYSTEM IS NEAR TROPICAL
STORM STRENGTH. IN ADDITION...SHIP WDE5381 LOCATED ABOUT 70 NMI
NORTH OF THE CENTER REPORTED AN EAST WIND OF 31 KT AT 06Z.
THEREFORE...THE INITIAL INTENSITY IS SET AT A CONSERVATIVE 30 KT.

THE INITIAL MOTION ESTIMATE IS 280/11. AN EXTENSIVE SUBTROPICAL
RIDGE LOCATED ACROSS MOST OF THE UNITED STATES AND EXTENDING
SOUTHWARD ACROSS THE GULF OF MEXICO AND INTO MAINLAND MEXICO IS
EXPECTED TO KEEP THE SYSTEM MOVING IN A GENERAL WEST-NORTHWESTWARD
DIRECTION THROUGHOUT THE FORECAST PERIOD. THE GFDL AND HWRF MODELS
ARE FORECASTING THE WESTERN PORTION OF THE RIDGE TO ERODE AFTER 72
HOURS...WHICH WOULD ALLOW THE CYCLONE TO TURN NORTHWESTWARD TOWARD
BAJA CALIFORNIA. HOWEVER...THESE APPEAR TO BE OUTLIER SOLUTIONS
GIVEN THE CURRENT STRENGTH OF THIS BROAD HEAT-WAVE DOME OF HIGH
PRESSURE. AS A RESULT...THE OFFICIAL FORECAST TRACK IS WELL SOUTH
OF THE GFDL/HWRF TRACKS AFTER AT 96 AND 120 HOURS...AND IS SIMILAR
TO BUT SLIGHTLY SOUTH OF THE GLOBAL MODEL CONSENSUS THROUGHOUT THE
FORECAST PERIOD.

SATELLITE IMAGERY INDICATES A WELL-DEFINED CURVED BAND OF CONVECTION
THAT IS INDICATIVE OF A DEVELOPING TROPICAL STORM. MICROWAVE AND
VISIBLE SATELLITE IMAGERY...PLUS THE AFOREMENTIONED SHIP
REPORT...ALSO SUGGEST THAT THE DEPRESSION HAS A FAIRLY TIGHT INNER
CORE WIND FIELD. ALL OF THIS WOULD INDICATE THAT RAPID
INTENSIFICATION IS A DISTINCT POSSIBILITY. HOWEVER...AN INHIBITING
FACTOR FOR THE NEXT 24 HOURS IS MODERATE NORTHERLY SHEAR...SO ONLY
STEADY STRENGTHENING IS FORECAST. BY 36 HOURS...THE SHEAR IS
EXPECTED TO DECREASE TO NEAR 5 KT...WHICH SHOULD ALLOW FOR
SIGNIFICANT INTENSIFICATION OF THE CYCLONE. THE OFFICIAL INTENSITY
FORECAST IS WELL ABOVE ALL OF THE STATISTICAL INTENSITY GUIDANCE
AND CLOSELY FOLLOWS THE GFDL AND HWRF MODELS THROUGH 96 HOURS.
AFTER THAT...RAPID WEAKENING IS FORECAST AS THE CYCLONE IS EXPECTED
TO MOVE OVER THE COLD WATER TROPICAL CYCLONE GRAVEYARD SITUATED
WEST OF 110W LONGITUDE.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  18/1500Z 10.6N  91.5W   30 KT  35 MPH
 12H  19/0000Z 10.7N  93.1W   40 KT  45 MPH
 24H  19/1200Z 11.3N  95.5W   55 KT  65 MPH
 36H  20/0000Z 12.3N  98.7W   70 KT  80 MPH
 48H  20/1200Z 13.6N 101.5W   85 KT 100 MPH
 72H  21/1200Z 16.6N 106.5W  105 KT 120 MPH
 96H  22/1200Z 18.8N 110.3W  100 KT 115 MPH
120H  23/1200Z 20.0N 113.0W   70 KT  80 MPH
 
$$
FORECASTER STEWART
 
NNNN


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Page last modified: Tuesday, 17-Jul-2012 13:44:13 UTC