WDPN31 PGTW 291500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 06W (SIX) WARNING
NR 01//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 06W (SIX), LOCATED APPROXIMATELY 394 NM
EAST-SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED NORTHWESTWARD AT
05 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY DEPICTS INCREASED CONSOLIDATION WITH DEVELOPING
CENTRAL CONVECTION OVER THE LOW LEVEL CIRCULATION CENTER (LLCC). A
291016Z SSMIS 91GHZ MICROWAVE IMAGE DEPICTS DEEP FORMATIVE BANDING
ALONG THE NORTHERN PERIPHERY WRAPPING INTO THE BROAD LLCC. THE
INITIAL POSITION IS PLACED WITH GOOD CONFIDENCE BENEATH THE BUILDING
CENTRAL CONVECTION AND IS SUPPORTED BY A 291321Z ASCAT BULLSEYE
SHOWING A SLIGHTLY ELONGATED LLCC. THE CURRENT INTENSITY IS ASSESSED
AT 25 KNOTS BASED ON THE IMPROVED CONVECTIVE STRUCTURE AND IS
SUPPORTED BY DVORAK INTENSITY ESTIMATES OF 25 KNOTS FROM ALL
AGENCIES AS WELL AS THE 291321Z ASCAT PASS SHOWING 25 KNOT WINDS
ALONG THE SOUTHERN PERIPHERY. THE IMPROVED CONVECTIVE STRUCTURE IS
SUPPORTED BY A FAVORABLE ENVIRONMENT WITH LOW (5-10 KNOT) VERTICAL
WIND SHEAR, RADIAL OUTFLOW, AND SEA SURFACE TEMPERATURES AROUND 30
CELSIUS. TD 06W IS DRIFTING SLOWLY NORTHWARD UNDER THE INFLUENCE OF
A WEAK LOW TO MID-LEVEL SUB-TROPICAL RIDGE (STR) TO THE EAST.
3. FORECAST REASONING.
   A. THIS IS THE INITIAL PROGNOSTIC REASONING AND SETS THE FORECAST
PHILOSOPHY.
   B. TD 06W WILL CONTINUE TO TRACK NORTHWARD THEN NORTHWESTWARD
UNDER THE INFLUENCE OF THE STR TO THE EAST. THE SYSTEM WILL SLOWLY
INTENSIFY OVER THE NEXT 12 HOURS AS IT CONTINUES TO CONSOLIDATE
AROUND THE LLCC. AFTERWARDS, EXPECT A PERIOD OF RAPID
INTENSIFICATION DUE TO THE AFOREMENTIONED ENVIRONMENTAL CONDITIONS
COMBINED WITH HIGH OCEAN HEAT CONTENT. NEAR TAU 48, THE CYCLONE WILL
BEGIN TO INTERACT WITH THE MOUNTAINOUS TERRAIN IN LUZON.
CONCURRENTLY, TD 06W WILL TURN TO A MORE NORTHWESTWARD TRAJECTORY,
CROSSING THE NORTHERN COAST OF LUZON, AS THE STR BUILDS IN NORTH OF
THE SYSTEM. DURING THIS PERIOD, TD 06W WILL WEAKEN SLIGHTLY DUE TO
LAND INTERACTION BEFORE REEMERGING OVER WARM WATER IN THE SOUTH
CHINA SEA. ENVIRONMENTAL CONDITIONS OVER THE SOUTH CHINA SEA WILL
REMAIN FAVORABLE ALLOWING THE CYCLONE TO REGAIN ITS PREVIOUS
INTENSITY.
   C. IN THE EXTENDED PERIOD, TD 06W WILL CONTINUE TO TRACK
NORTHWESTWARD TOWARDS HONG KONG. FAVORABLE ENVIRONMENTAL CONDITIONS
IN THE SOUTH CHINA SEA WILL SUPPORT ADDITIONAL INTENSIFICATION TO 75
KNOTS JUST PRIOR TO LANDFALL NEAR TAU 96. EXPECT THE SYSTEM TO
RAPIDLY DETERIORATE AS IT MOVES FURTHER INLAND. DYNAMIC MODEL
GUIDANCE IS IN UNUSUALLY TIGHT AGREEMENT SUPPORTING HIGH CONFIDENCE
IN THE INITIAL JTWC TRACK FORECAST.//