Tropical Storm HALONG Advisory Ter, 05-11

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 24W (HALONG) WARNING NR
012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   SUPER TYPHOON (STY) 24W (HALONG), LOCATED APPROXIMATELY 427 NM
NORTHEAST OF TINIAN, HAS TRACKED NORTHWESTWARD AT 08 KNOTS OVER THE
PAST SIX HOURS. STY 24W HAS A 9 NM WIDE EYE, LENDING GOOD CONFIDENCE
TO THE INITIAL POSITION. THE CURRENT INTENSITY IS ASSESSED AT 130
KNOTS BASED ON MULTI-AGENCY DVORAK INTENSITY ESTIMATES RANGING FROM
T6.5-7.0 (127-140 KNOTS), SUPPORTED BY A 050300Z SATCON ESTIMATE OF
132 KNOTS. UPPER-LEVEL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT
WITH ROBUST POLEWARD OUTFLOW AND LOW (5-10 KT) VERTICAL WIND SHEAR
(VWS). SEA SURFACE TEMPERATURES REMAIN FAVORABLE (29 DEGREES
CELSIUS) FOR FURTHER DEVELOPMENT. STY 24W IS TRACKING ALONG THE
WESTERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR)
POSITIONED TO THE EAST.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. A MIDLATITUDE TROUGH IS GRADUALLY ERODING THE STEERING STR TO
THE EAST OF STY 24W. STY 24W WILL TRACK NORTH-NORTHWESTWARD TO
NORTHWARD THROUGH TAU 24 THEN GRADUALLY RECURVE AS IT ROUNDS THE STR
AXIS AFTER TAU 24. AFTER TAU 24, STY 24W WILL ACCELERATE NORTH-
NORTHEASTWARD. THE SYSTEM WILL INTENSIFY UNDER FAVORABLE CONDITIONS
TO A PEAK OF 135 KNOTS BY TAU 12 DUE TO ENHANCED POLEWARD OUTFLOW
FROM THE AFOREMENTIONED MIDLATITUDE TROUGH TO THE NORTHWEST. STY 24W
WILL BEGIN TO WEAKEN AFTER TAU 12 DUE TO INCREASING VWS AND SLOW
TRACK MOTION OVER WATERS WITH LOW OCEAN HEAT CONTENT (OHC).
   C. IN THE EXTENDED PERIOD, STY 24W WILL ACCELERATE NORTHEASTWARD
AS IT TRACKS WITHIN THE MIDLATITUDE WESTERLIES. IT IS EXPECTED TO
BEGIN INTERACTING WITH THE BAROCLINIC ZONE AT TAU 72 AND COMPLETE
ETT BY TAU 96 AS IT GAINS FRONTAL CHARACTERISTICS. AFTER TAU 72, STY
24W WILL WEAKEN RAPIDLY DUE TO INCREASING VWS UNDER THE MIDLATITUDE
WESTERLIES AND COOLING SSTS DROPPING BELOW 26 DEGREES CELSIUS.
NAVGEM IS THE EASTERN OUTLIER SHOWING A TIGHTER RECURVE. OTHERWISE,
THE NUMERICAL MODELS ARE IN GOOD AGREEMENT WITH THE TRACK AND TIMING
OF THE RECURVE, ALTHOUGH THERE ARE DIFFERENCES IN ALONG-TRACK SPEED
AFTER TAU 72. THE JTWC FORECAST TRACK IS PLACED NEAR THE MULTI-MODEL
CONSENSUS. THEREFORE, THERE IS HIGH OVERALL CONFIDENCE IN THE JTWC
TRACK FORECAST.//
NNNN
NNNN