Tropical Storm PABUK Advisory Ter, 01-01

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 36W (THIRTYSIX)
WARNING NR 005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 36W (THIRTYSIX), LOCATED APPROXIMATELY
354 NM SOUTHEAST OF HO CHI MINH CITY, VI, HAS TRACKED SOUTHWESTWARD
AT 08 KNOTS (KTS) OVER THE PAST SIX HOURS. THE INITIAL POSITION IS
PLACED WITH HIGH CONFIDENCE BASED ON ANIMATED ENHANCED MULTISPECTRAL
SATELLITE IMAGERY (MSI) WHICH SHOWS A PARTIALLY EXPOSED LOW LEVEL
CIRCULATION CENTER (LLCC) WITH DEEP CONVECTION JUST WEST OF THE
LLCC. THE INITIAL INTENSITY OF 30 KNOTS IS BASED ON MULTI-AGENCY
DVORAK CURRENT INTENSITY ESTIMATES OF T2.0 (30 KTS). THE SURROUNDING
ENVIRONMENT IS MARGINAL WITH MODERATE TO HIGH (20-30 KTS) VERTICAL
WIND SHEAR (VWS), EXCELLENT POLEWARD OUTFLOW, AND WARM (27-28
CELSIUS) SEA SURFACE TEMPERATURE (SST) IN THE SOUTH CHINA SEA AND
GULF OF THAILAND. THE CYCLONE IS TRACKING ALONG THE SOUTHERN
PERIPHERY OF A SUBTROPICAL RIDGE (STR) TO THE NORTH.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY FROM THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TD 36W IS EXPECTED TO SLOWLY TURN NORTHWESTWARD OVER THE NEXT
48 HOURS AS IT CONTINUES TO TRACK ALONG SOUTH OF THE STR. MODERATE
VWS AND MARGINAL SST WILL LIMIT INTENSIFICATION TO A PEAK OF 40 KTS
BY TAU 36. THE INTENSITY FORECAST IS NEAR THE CONSENSUS AND
REPRESENTS AN AVERAGE BETWEEN THE MORE INTENSE COAMPS-NAVGEM AND
COAMPS-GFS SOLUTIONS AND THE LESS INTENSE HWRF SOLUTION. WITH THE
EXCEPTION OF NAVGEM AND JGSM, MOST OF THE MODEL GUIDANCE IS CLOSELY
ALIGNED WITH THE JTWC FORECAST TRACK THROUGH TAU 72.
   C. BEYOND TAU 72, TD 36W WILL CONTINUE TO TRACK NORTHWESTWARD
ALONG THE SOUTHWESTERN PERIPHERY OF THE STR WHILE LAND INTERACTION
AND MARGINALLY FAVORABLE ENVIRONMENTAL CONDITIONS WILL CAUSE TD 36W
TO WEAKEN SLIGHTLY. ALTHOUGH THE OFFICIAL FORECAST CALLS FOR THE
CYCLONE TO WEAKEN, THE COAMPS MODELS MAINTAIN THE INTENSITY OF TD
36W AT TROPICAL STORM STRENGTH THROUGHOUT THE FORECAST. SPREAD IN
THE NUMERICAL MDOEL GUIDANCE IS 380 NM BY TAU 120, HOWEVER,
ELIMINATING NAVGEM (NORTHERN OUTLIER) AND JGSM (SOUTHERN OUTLIER)
REDUCES THE SPREAD TO 176 NM, LENDING TO FAIR CONFIDENCE IN THE JTWC
TRACK FORECAST.//
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