WDPN32 PGTW 080900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 28W (HALONG) WARNING NR 016//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 30.5N 137.8E
   INITIAL INTENSITY: 120 KTS
   GEOGRAPHIC REFERENCE: 293 NM SOUTH OF CAMP FUJI
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 50 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TYPHOON (TY) 
28W (HALONG) WITH AN EVIDENT EYE FEATURE THAT HAS BECOME LESS
SYMMETRICAL OVER THE PAST 6 HOURS. THE ASSOCIATED CONVECTION
OUTSIDE OF THE EYEWALL HAS SUSTAINED TEMPERATURES BETWEEN -73 AND
-75 C. STRONG RADIAL OUTFLOW PERSISTS. ENVIRONMENTAL CONDITIONS ARE
NOW MARGINALLY FAVORABLE WITH THE SYSTEM REACHING AN AREA OF ELEVATED 
VERTICAL WIND SHEAR (BETWEEN 15-20 KTS), SLIGHTLY COOLER SEA 
TEMPERATURES (27-28 C), AS WELL AS DRY AIR IN THE VICINITY, THOUGH 
NOT YET PENETRATING THE CORE. THE INITIAL POSITION IS PLACED WITH 
HIGH CONFIDENCE BASED ON THE OBSERVABLE EYE FEATURE ON ANIMATED MSI. 
THE INITIAL INTENSITY IS ASSESSED WITH HIGH CONFIDENCE BASED ON
SUBJECTIVE AGENCY DVORAK ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE SOUTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.0 - 115 KTS
   RJTD: T6.5 - 127 KTS
   RCTP: T6.5 - 127 KTS
   KNES: T6.0 - 115 KTS
   CIMSS SATCON: 127 KTS AT 080353Z
   CIMSS ADT: 115 KTS AT 080700Z
   CIMSS AIDT: 111 KTS AT 080700Z
   CIMSS D-MINT: 115 KTS AT 080353Z
   CIMSS D-PRINT: 121 KTS AT 080700Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15-20 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: HIGH

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TY 28W IS FORECAST TO CONTINUE ON A EAST-
NORTHEASTWARD TRACK AROUND THE WESTERN-MOST EXTENT OF THE DEEP-LAYER 
SUBTROPICAL RIDGE TO THE SOUTHEAST. THIS MOVEMENT WILL CONTINUE 
THROUGH THE REMAINDER OF THE FORECAST WITH THE RIDGE CONTINUING TO 
STEER THE SYSTEM NORTHEAST AS IT TRANSITION TO ITS EXTRATROPICAL 
PHASE. WITH REGARD TO INTENSITY, TYPHOON HALONG IS FORECASTED TO 
MAINTAIN AROUND 120 KTS OVER THE NEXT 12 HOURS AND THEN START TO 
WEAKEN AS IT CONTINUES IN THE FORECASTED MARGINAL ENVIRONMENT. BY TAU 
24, VWS (20+ KTS), DRY AIR WRAPPING INTO THE SOUTHERN SEMICIRCLE, AND 
COOLER SEA SURFACE TEMPERATURES (26-27 C) WILL BRING TY 28W DOWN TO 
115 KTS. THE EXTRATROPICAL TRANSITION WILL RAPIDLY PROGRESS AND BY 
TAU 72, TY 28W IS FORECASTED TO BECOME FULLY EXTRATROPICAL, WHILE 
MAINTAINING SURFACE INTENSITIES OF 45 KTS UNDER THE INFLUENCE OF THE
MID-LATITUDE UPPER-LEVEL JET.

MODEL DISCUSSION: NUMERICAL WEATHER PREDICTION GUIDANCE REMAINS IN
GREAT AGREEMENT THAT TY 28W WILL CONTINUE ON A EAST-NORTHEASTWARD
TRACK WITH A CROSS-TRACK SPREAD OF 20 NM AT TAU 36. THE JTWC TRACK
FORECAST IS PLACED WITH HIGH CONFIDENCE THROUGHOUT THE ENTIRETY OF
THE FORECAST PERIOD AND ALIGNED CLOSELY WITH THE MULTI-MODEL 
CONSENSUS. MOST OF THE JTWC INTENSITY GUIDANCE ENVELOPE MEMBERS 
ILLUSTRATE STEADY INTENSITIES OVER THE NEXT 12 HOURS, AND A
SHARP WEAKENING PHASE UNTIL THE END OF THE FORECAST PERIOD. ONLY
HAFS SHOWS POTENTIAL INTENSIFICATION TO 125 KTS OVER THE NEXT 12
HOURS, AND A WEAKENING PHASE THEREAFTER. THE JTWC INTENSITY
FORECAST IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE MAJORITY OF
CONSENSUS MEMBERS AND QUICK RATE OF DECAY AS THE SYSTEM UNDERGOES
EXTRATROPICAL TRANSITION.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   INTENSITY 00-72 HR: HIGH//
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