Tropical Storm FOURTEEN Advisory lun, 03-08

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 14W (FOURTEEN)
WARNING NR 04//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 14W (FOURTEEN), LOCATED APPROXIMATELY
340 NM SOUTH-SOUTHEAST OF YOKOSUKA, JAPAN, HAS TRACKED NORTHWESTWARD
AT 03 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY (MSI) DEPICTS A FULLY EXPOSED, TIGHTLY CURVED LOW
LEVEL CIRCULATION CENTER WITH 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 022150Z SSMIS 91GHZ
MICROWAVE IMAGE CONTINUES TO SHOW DRY AIR SURROUNDING THE CYCLONE.
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 ABOVE 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 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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