Tropical Depression FOUR-E

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TROPICAL DEPRESSION FOUR-E DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2 AM PDT MON JUL 04 2005
 
TROPICAL DEPRESSION FOUR-E CONTINUES TO BECOME BETTER ORGANIZED THIS
MORNING.  SATELLITE IMAGERY SHOWS A LARGE MASS OF COLD CONVECTION
WITH TOPS TO -85C...WITH RADAR IMAGERY FROM ACAPULCO SHOWING THE
CENTER ON THE SOUTHERN EDGE OF THE CONVECTION.  SATELLITE INTENSITY
ESTIMATES ARE 30 KT FROM ALL AGENCIES...SO THAT REMAINS THE INITIAL
INTENSITY.

THE INITIAL MOTION IS A SOMEWHAT UNCERTAIN 330/6.  LARGE-SCALE
MODELS SHOW THE DEPRESSION IS SOUTH OF LOW/MID-LEVEL RIDGE...WHILE
WATER VAPOR IMAGERY INDICATES THAT A MID/UPPER-LEVEL TROUGH OVER
THE GULF OF MEXICO EXTENDS SOUTH INTO SOUTH CENTRAL MEXICO.  THIS
TROUGH IS HELPING TO PRODUCE THE CURRENT NORTH-NORTHWESTWARD
MOTION.  THE MODELS SUGGEST THE TROUGH SHOULD WEAKEN OVER THE NEXT
72 HR...WHICH SHOULD CAUSE THE DEPRESSION TO TURN NORTHWESTWARD OR
WEST-NORTHWESTWARD.  NHC TRACK GUIDANCE AGREES WITH THIS
SCENARIO...AS WILL THE OFFICIAL FORECAST.  THE TRACK FORECAST IS
SHIFTED SOMEWHAT TO THE RIGHT OF THE PREVIOUS PACKAGE BASED ON THE
CURRENT POSITION AND MOTION.  IT SHOULD BE NOTED THAT MOTION TO THE
RIGHT OF THE FORECAST TRACK COULD BRING THE CENTER ONTO THE MEXICAN
COAST AT ALMOST ANY TIME DURING THE NEXT 48 HR.
 
THE DEPRESSION IS CURRENTLY IN A MODERATE EASTERLY SHEAR
ENVIRONMENT...WITH LARGE-SCALE MODELS FORECASTING THIS TO CONTINUE
FOR THE NEXT DAY OR TWO.  THUS...THE CYCLONE SHOULD STRENGTHEN INTO
A TROPICAL STORM.  THE BIGGEST SHORT-TERM QUESTION IS HOW FAR WILL
THE CENTER BE FROM SHORE...AS ANY MOTION TO THE RIGHT OF THE
FORECAST TRACK COULD BRING THE CYCLONE CLOSE ENOUGH TO THE
MOUNTAINS OF SOUTHERN MEXICO TO SLOW OR STOP DEVELOPMENT.  THE
INTENSITY FORECAST IS BASED ON THE PREMISE THAT THE CENTER WILL
STAY FAR ENOUGH OFFSHORE FOR INTENSIFICATION TO OCCUR AND CALLS FOR
55 KT WINDS IN 36 KT.  THIS IS SLIGHTLY LESS THAT THE 55-60 KT
FORECAST BY SHIPS AND THE 60-65 KT FORECAST BY THE GFDL.  AFTER 72
HR...THE CYCLONE SHOULD WEAKEN OVER COOLER WATER.

FORECASTER BEVEN
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      04/0900Z 15.4N 100.0W    30 KT
 12HR VT     04/1800Z 16.0N 100.5W    40 KT
 24HR VT     05/0600Z 16.8N 101.5W    45 KT
 36HR VT     05/1800Z 17.7N 102.8W    55 KT
 48HR VT     06/0600Z 18.5N 104.5W    55 KT
 72HR VT     07/0600Z 19.5N 107.5W    55 KT
 96HR VT     08/0600Z 20.0N 111.0W    45 KT
120HR VT     09/0600Z 20.5N 116.0W    25 KT...DISSIPATING
 
 
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