Tropical Storm RAI Advisory 12.09.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 19W (NINETEEN)
WARNING NR 02//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION 19W (NINETEEN), LOCATED APPROXIMATELY 182 NM
SOUTHEAST OF DA NANG, VIETNAM, HAS TRACKED NORTHWESTWARD AT 16 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
(MSI) DEPICTS AN EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) THAT
HAS MOVED OUT FROM UNDERNEATH THE DEEPER CONVECTION WRAPPING AROUND
THE SOUTHERN PERIPHERY. THE INITIAL POSITION IS PLACED WITH GOOD
CONFIDENCE. A 120233Z METOP-B 89GHZ MICROWAVE IMAGE SHOWS DEEP
CONVECTION SPARSELY SCATTERED AROUND THE LLCC, AND THE CORRESPONDING
120233Z ASCAT PASS SHOWS 30 KNOT WINDS IN THE NORTHEAST QUADRANT AND
SOUTHERN SEMICIRCLE. THUS, THE INITIAL INTENSITY IS ASSESSED AT 30
KNOTS. TD 19W CONTINUES TO TRACK WEST-NORTHWESTWARD ALONG THE
SOUTHERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE, EXCEPT FOR SLIGHTLY FASTER
FORWARD MOTION.
   B. TD 19W IS FORECAST TO TRACK WEST-NORTHWESTWARD UNDER THE
STEERING INFLUENCE OF THE STR. GIVEN THAT THE LLCC HAS ACCELERATED
TOWARD THE WEST-NORTHWEST, LANDFALL IN VIETNAM IS LIKELY WITHIN THE
NEXT 6 TO 12 HOURS, FOLLOWED BY WEAKENING AND DISSIPATION OVER LAND.
LITTLE CHANGE IN INTENSITY IS FORECAST PRIOR TO LANDFALL. AVAILABLE
DYNAMIC MODEL TRACKERS ARE IN TIGHT AGREEMENT, THEREFORE, THERE IS
HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.//
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