752
WTPZ44 KNHC 120206
TCDEP4
TROPICAL DEPRESSION FOUR-E DISCUSSION NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP042006
800 PM PDT TUE JUL 11 2006
CONVENTIONAL AND MICROWAVE SATELLITE DATA INDICATE THE LARGE
TROPICAL DISTURBANCE LOCATED OFF THE SOUTHWESTERN COAST OF MEXICO
HAS ACQUIRED ENOUGH CONVECTIVE BANDING FEATURES TO BE DESIGNATED
TROPICAL DEPRESSION FOUR-E. THE INITIAL INTENSITY OF 30 KT IS BASED
ON A BLEND OF DVORAK SATELLITE INTENSITY ESTIMATES OF T2.5/35 KT
AND T1.5/25 KT FROM TAFB AND SAB...RESPECTIVELY. IN ADDITION...AT
12/00Z SHIPS A8AL6 AND SIWB REPORTED SOUTHEAST WINDS OF 25 KT AND
24 KT...RESPECTIVELY...IN THE NORTHEASTERN QUADRANT JUST SOUTH OF
ACAPULCO MEXICO. SHIP SIWB ALSO REPORTED 11 FT SEA HEIGHTS.
THE INITIAL MOTION ESTIMATE OF 295/11 KT IS SOMEWHAT UNCERTAIN DUE
TO THE BROAD INNER-CORE WIND FIELD. THERE MAY BE SOME JUMPING
AROUND OF THE CIRCULATION CENTER AS IT REFORMS NEAR ANY NEW CENTRAL
CONVECTION THAT DEVELOPS. HOWEVER...THE NHC MODEL GUIDANCE IS
TIGHTLY PACKED ABOUT A GENERAL WEST-NORTHWESTWARD MOTION THROUGHOUT
THE FORECAST PERIOD. THE CYCLONE IS EXPECTED TO PARALLEL THE
SOUTHWESTERN COAST OF MEXICO FOR THE NEXT 24 TO 36 HOURS...BEFORE
FINALLY TURNING MORE WESTWARD AND MOVING AWAY FROM THE MEXICAN
COAST. AFTER 72 HOURS...THE MODELS DIVERGE SIGNIFICANTLY WITH THE
GFS...GFDL...AND UKMET MODELS TAKING THE CYCLONE SLOWLY
NORTHWESTWARD... WHILE THE NOGAPS...CANADIAN...ECMWF...AND THE BAM
MODELS FAVOR A FASTER WESTWARD MOTION. HOWEVER...SINCE ALL OF THE
MODELS AGREE THAT A LARGE HIGH-AMPLITUDE MID- TO UPPER-LEVEL TROUGH
IS EXPECTED TO DIG SOUTHWARD AND ERODE THE RIDGE AXIS BETWEEN
130-150W LONGITUDE... THE OFFICIAL FORECAST LEANS MORE TOWARD THE
GFS-GFDL-UKMET SOLUTION.
THE UPPER-LEVEL OUTFLOW PATTERN IS GOOD AND IS EXPECTED TO IMPROVE
THROUGHOUT THE FORECAST PERIOD. AN UPPER-LEVEL LOW CURRENTLY
LOCATED TO THE NORTH OF THE DEPRESSION NEAR MANZANILLO MEXICO IS
FORECAST TO MOVE WESTWARD IN TANDEM WITH THE CYCLONE. THIS FEATURE
SHOULD ACT TO ENHANCE THE OUTFLOW ON THE NORTH SIDE OF THE
DEPRESSION AND ALLOW FOR STEADY STRENGTHENING. THE ONLY HINDRANCES
TO THE INTENSIFICATION PROCESS APPEAR TO BE THE LARGE SIZE OF THE
DISTURBANCE AND MUCH COOLER WATER THAT THE CYCLONE WILL BE PASSING
OVER AFTER 72 HOURS. IF MORE DEEP CONVECTION DEVELOPS IN THE INNER-
CORE REGION DURING THE NEXT 24-36 HOURS...THEN THIS SYSTEM COULD
BECOME STRONGER BEFORE IT REACHES COOLER WATER IN 72 HOURS.
ALTHOUGH THE CENTER OF THE DEPRESSION IS FORECAST TO REMAIN WELL
OFFSHORE...A PUBLIC ADVISORY PRODUCT HAS BEEN AND WILL CONTINUE TO
BE ISSUED AS LONG AS THE THREAT FOR HEAVY RAINFALL AND POSSIBLE
FLOODING EXISTS ALONG THE SOUTHWESTERN COAST OF MEXICO.
FORECAST POSITIONS AND MAX WINDS
INITIAL 12/0300Z 14.4N 102.8W 30 KT
12HR VT 12/1200Z 15.2N 104.7W 35 KT
24HR VT 13/0000Z 16.0N 107.2W 45 KT
36HR VT 13/1200Z 16.8N 109.6W 55 KT
48HR VT 14/0000Z 17.4N 111.8W 65 KT
72HR VT 15/0000Z 18.1N 115.4W 75 KT
96HR VT 16/0000Z 19.5N 118.0W 60 KT
120HR VT 17/0000Z 22.0N 120.0W 40 KT
$$
FORECASTER STEWART
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