WDPN31 PGTW 270800
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (MIRINAE) WARNING
NR 08//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 05W (MIRINAE), LOCATED APPROXIMATELY 99 NM
SOUTHEAST OF HANOI, VIETNAM, HAS TRACKED WEST-NORTHWESTWARD AT 14
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY DEPICTS AN ELONGATING LOW LEVEL CIRCULATION CENTER (LLCC)
WITH DEEP CONVECTION SHEARED TO THE SOUTHWEST DUE TO PERSISTENT 15
TO 20 KNOT NORTHEASTERLY VERTICAL WIND SHEAR (VWS). THE ELONGATED
LLCC IS FURTHER ILLUSTRATED IN A 270421Z GPM 36GHZ MICROWAVE IMAGE
WHICH SHOWS DEFINED SHALLOW BANDING WRAPPING INTO THE NORTH-SOUTH
ELONGATED CENTER. THE CURRENT POSITION IS PLACED WITH FAIR
CONFIDENCE JUST BEYOND THE LLCC IN THE GPM IMAGE AND IS SUPPORTED BY
FIXES FROM PGTW AND RJTD. THE CURRENT INTENSITY IS HELD AT 35 KNOTS
BASED ON 35 KNOT WINDS SEEN IN A 270251Z ASCAT BULLSEYE AND DVORAK
INTENSITY ESTIMATES OF T2.5 (35 KNOTS) FROM ALL AGENCIES.
ENVIRONMENTAL CONDITIONS REMAIN MARGINALLY-FAVORABLE WITH STRONG
DIVERGENT OUTFLOW AND WARM SEA SURFACE TEMPERATURES OFFSETTING THE
AFOREMENTIONED VWS. THESE CONDITIONS ARE SUSTAINING THE CURRENT
CONVECTIVE STRUCTURE. TS 05W CONTINUES TO TRACK ALONG THE SOUTH-
WESTERN PERIPHERY OF AN ELONGATED LOW TO MID-LEVEL SUB-TROPICAL
RIDGE TO THE NORTHEAST.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TS MIRINAE WILL CONTINUE TRACKING WEST-NORTHWESTWARD
THROUGHOUT THE FORECAST PERIOD. THE CYCLONE WILL MAKE LANDFALL OVER
THE NEXT COUPLE HOURS IN NORTHERN VIETNAM. ALTHOUGH ENVIRONMENTAL
CONDITIONS COULD SUPPORT A MODEST INTENSIFICATION JUST PRIOR TO
LANDFALL, THE IMPENDING LAND INTERACTION WILL QUICKLY ERODE THE
LLCC. THIS WILL LEAD TO ITS FULL DISSIPATION BY THE END OF THE
FORECAST PERIOD OR POSSIBLY SOONER. DYNAMIC MODEL GUIDANCE CONTINUES
TO SHOW A SPREAD ONCE THE SYSTEM MAKES LANDFALL OVER VIETNAM DUE TO
ITS RAPID DISSIPATION. THE JTWC TRACK FORECAST IS LAID WITH HIGH
CONFIDENCE JUST SOUTH OF THE MULTI-MODEL CONSENSUS DUE TO THE
ORIENTATION OF THE LOW LEVEL RIDGE AND IS SUPPORTED BY THE ECMWF AND
NAVGEM MODEL SOLUTIONS./=