Tropical Storm FOURTEEN Advisory Tue Aug 04

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 14W (FOURTEEN)
WARNING NR 05//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 14W (FOURTEEN), LOCATED APPROXIMATELY
216 NM NORTH OF CHICHI JIMA, HAS TRACKED WEST-NORTHWESTWARD AT 06
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) DEPICTS A FULLY EXPOSED, TIGHTLY CURVED LOW-LEVEL
CIRCULATION CENTER (LLCC) WITH ISOLATED DEEP CONVECTION SHEARED
ALONG THE EASTERN PERIPHERY DUE TO PERSISTENT 20 KNOT WESTERLY
VERTICAL WIND SHEAR (VWS). THE INITIAL POSITION IS BASED ON THE
EXPOSED LLCC IN THE MSI LOOP WITH HIGH CONFIDENCE. A 030046Z ASCAT
PASS REVEALED A WELL DEFINED LLCC WITH 25 TO 30 KNOT WINDS ALONG THE
NORTHERN PERIPHERY WHICH SUPPORTS THE CURRENT INTENSITY. A 030455Z
SSMI 85GHZ IMAGE CONTINUES TO SHOW A SYMMETRIC LLCC WITH TIGHTLY-
CURVED SHALLOW BANDING AND DRY AIR SURROUNDING THE SYSTEM. UPPER-
LEVEL ANALYSIS INDICATES A MARGINAL ENVIRONMENT DUE TO THE DRY
AIR AROUND THE SYSTEM AND MODERATE VWS. WATER VAPOR IMAGERY SHOWS
GOOD POLEWARD OUTFLOW; HOWEVER, THE VWS IS PREVENTING CONVECTION
FROM BUILDING OVER THE LLCC. TD 14W IS TRACKING ALONG THE SOUTHERN
PERIPHERY OF THE LOW LEVEL SUB-TROPICAL RIDGE (STR).
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TD 14W IS FORECAST TO TRACK SLOWLY WESTWARD TO WEST-
NORTHWESTWARD THROUGHOUT THE FORECAST PERIOD UNDER THE STEERING
INFLUENCE OF THE STEERING STR. ENVIRONMENTAL CONDITIONS ARE FORECAST
TO DETERIORATE AS AN APPROACHING MID-LATITUDE TROUGH ENGULFS THE
SYSTEM, INCREASING THE VWS AND SUBSIDENCE. THIS WILL CAUSE TD 14W TO
WEAKEN AND FULLY DISSIPATE OVER WATER BY THE END OF THE FORECAST
PERIOD. DYNAMIC GUIDANCE IS IN FAIR AGREEMENT WITH A GENERAL
WESTWARD TRACK AND SUPPORTS THE JTWC FORECAST TRACK WITH HIGH
CONFIDENCE.//
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