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TROPICAL DEPRESSION FOUR-E DISCUSSION NUMBER 3
NATIONAL WEATHER SERVICE MIAMI FL
2 AM PDT FRI JUL 07 2000
TROPICAL DEPRESSION FOUR-E IS STRUGGLING...TO SAY THE LEAST...AND IS
DEVOID OF ANY SIGNIFICANT DEEP CONVECTION. HOWEVER...THE SYSTEM IS
LOCATED BENEATH A SMALL ANTICYCLONE BASED ON WATER VAPOR AND IR
SATELLITE IMAGERY AND OUTFLOW IS GOOD TO THE SOUTH. 0151Z AND 0159Z
MICROWAVE WINDS SUPPORT A 20 TO 25 KT DEPRESSION AND NIGHT TIME
VISIBLE IMAGERY INDICATE A TIGHT LOW-LEVEL SWIRL STILL REMAINS...
ALBEIT VERY SMALL.
INITIAL MOTION IS 275/10. THE OFFICIAL FORECAST TRACK IS SIMPLY AN
UPDATE OF THE PREVIOUS FORECAST. TD FOUR-E REMAINS EMBEDDED WITHIN A
DEEP EASTERLY STEERING FLOW ON THE SOUTH SIDE OF THE LARGE
SUBTROPICAL RIDGE TO NORTH WHICH SHOULD KEEP THE SYSTEM ON A GENERAL
WESTERLY COURSE. THE FORECAST TRACK IS CLOSE TO THE UKMET AND CLIPER
MODEL FORECASTS.
I AM HOLDING ON TO THE SYSTEM MAINLY DUE TO THE CONVECTIVE
FLUCTUATIONS THAT HAVE OCCURRED DURING THE PREVIOUS 2 DAYS WITH
INCREASING CONVECTION AT NIGHT AND DECREASING CONVECTION DURING THE
DAY. HOWEVER...UNLESS DEEP CONVECTION RE-DEVELOPS NEAR THE SYSTEM
CENTER WITHIN THE NEXT 6 TO 12 HOURS...TD FOUR-E WILL RAPIDLY WEAKEN
AND LIKELY DISSIPATE WITHIN 24 HOURS. AFTER 48 HOURS...UPPER-LEVEL
WESTERLY SHEAR IS FORECAST TO INCREASE AND THIS WILL LIKELY KILL OFF
THE SYSTEM...IF IT IS EVEN STILL AROUND AT THAT TIME.
FORECASTER STEWART
FORECAST POSITIONS AND MAX WINDS
INITIAL 07/0900Z 13.2N 123.4W 25 KTS
12HR VT 07/1800Z 13.4N 124.9W 25 KTS
24HR VT 08/0600Z 13.7N 126.8W 30 KTS
36HR VT 08/1800Z 14.0N 129.0W 30 KTS
48HR VT 09/0600Z 14.5N 131.0W 30 KTS...DISSIPATING
72HR VT 10/0600Z 14.5N 135.0W 25 KTS...DISSIPATING
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