WDPN32 PGTW 090900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 28W (HALONG) WARNING NR 020//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 33.6N 143.6E
   INITIAL INTENSITY: 95 KTS
   GEOGRAPHIC REFERENCE: 218 NM EAST-SOUTHEAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: EAST-NORTHEASTWARD AT 22 KTS
   SIGNIFICANT WAVE HEIGHT: 45 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THAT THE EYE
OF TYPHOON (TY) HALONG HAS CLOSED, RAPIDLY BECOMING CLOUD-FILLED
OVER THE PAST FEW HOURS. THE BROADER ROTATION ASSOCIATED WITH THE
LOW LEVEL CIRCULATION CENTER (LLCC) IS STILL EVIDENT IN THE MSI AS
WELL AS THE INFRARED IMAGERY, WITH A RELATIVELY WARMER CENTER
SURROUNDED BY ISOLATED POCKCETS OF DEEP CONVECTION AND COLD CLOUD 
TOPS. A
090533Z SSMIS 89GHZ MICROWAVE IMAGE REVEALED A BROAD UPPER-LEVEL
MICROWAVE EYE FEATURE, WITH WEAK CONVECTIVE BANDING ACROSS THE
SOUTHERN HEMISPHERE OF THE LLCC, AND MORE SIGNIFICANT CONVECTIVE
BANDS TO THE NORTH. THE 37GHZ IMAGE REVEALED A STRONG LOW
EMISSIVITY REGION (LER) INDICATIVE OF THE LOWER-LEVEL CENTER, WHICH
WAS DISPLACED A BIT TO THE SOUTHWEST OF THE UPPER-LEVEL CENTER DUE
TO VERY STRONG SOUTHWESTERLY SHEAR. THE INITIAL POSITION IS
ASSESSED WITH HIGH CONFIDENCE BASED ON THE MICROWAVE IMAGERY
DISCUSSED ABOVE. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON A BLEND OF THE OBJECTIVE AND SUBJECTIVE FIXES
NOTED BELOW. ENVIRONMENTAL CONDITIONS CONTINUE TO RAPIDLY
DETERIORATE, WITH MARGINAL SSTS (26-27C), AND EXTREMELY HIGH SHEAR
(40-45 KTS) THOUGH AT PRESENT THE ROBUST POLEWARD OUTFLOW AND THE
FACT THAT THE STORM MOTION IS IN PHASE WITH THE SHEAR VECTOR, IS
OFFSETTING THE SHEAR SOMEWHAT AND THE VORTEX HAS NOT YET FULLY
DECOUPLED.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: NORTHWESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED TO THE SOUTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.0 - 115 KTS
   RJTD: T5.5 - 102 KTS
   KNES: T5.5 - 102 KTS
   CIMSS SATCON: 107 KTS AT 090500Z
   CIMSS ADT: 94 KTS AT 090530Z
   CIMSS AIDT: 91 KTS AT 090530Z
   CIMSS D-MINT: 89 KTS AT 090533Z
   CIMSS D-PRINT: 84 KTS AT 090600Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 30+ KTS
   SST: 26-27 CELSIUS
   OUTFLOW: STRONG POLEWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TY 28W CONTINUES TO ACCELERATE TO THE
NORTHEAST, HAVING ROUNDED THE STR AXIS. THE RIDGE CURRENTLY
POSITIONED TO THE SOUTHEAST IS FORECAST TO QUICKLY SLIDE WESTWARD
OVER THE NEXT DAY AND A HALF AND BY THE END OF THE FORECAST WILL BE
POSITIONED SOUTH OF TOKYO. TY 28W IS FORECAST TO TRACK
EAST-NORTHEASTWARD ALONG THE NORTH SIDE OF THIS RIDGE, THROUGH THE
FORECAST PERIOD, CONTINUING TO ACCELERATE AS IT MOVES FURTHER INTO
THE NORTH PACIFIC. THE SYSTEM IS ALREADY BEGINNING THE EARLY STAGES
OF EXTRATROPICAL TRANSITION (ETT) WITH WEAK THERMAL ADVECTION
BEGINNING TO APPEAR, PARTICULARLY ON THE BACK SIDE OF THE SYSTEM.
OVER THE COURSE OF THE NEXT 12 HOURS, TY 28W WILL CROSS THE 26C SST
ISOTHERM, BEGIN TO INTERACT WITH THE 200MB JET MAX TO THE NORTH AND
BEGIN FRONTOGENESIS. THESE PROCESSES WILL ALSO INDUCE RAPID
WEAKENING, WITH VORTEX DECAPITATION EXPECTED WITHIN 24 HOURS, WITH
THE INTENSITY EXPECTED TO DROP TO NEAR 55 KNOTS BY THE END OF THE
FORECAST PERIOD. 

MODEL DISCUSSION: DETERMINISTIC AND ENSEMBLE TRACK GUIDANCE IS IN
EXTREMELY GOOD AGREEMENT WITH MINIMAL CROSS- OR ALONG-TRACK SPREAD
THROUGH TAU 24, AND ONLY A SLIGHT INCREASE IN CROSS-TRACK SPREAD BY
TAU 36. THE JTWC FORECAST IS PLACED NEAR THE CONSENSUS MEAN WITH
HIGH CONFIDENCE THROUGH THE ENTIRETY OF THE FORECAST. INTENSITY
GUIDANCE IS ALSO IN GOOD AGREEMENT, SHOWING THE ONSET OF RAPID
WEAKENING IMMINENTLY. THE JTWC FORECAST IS PLACED NEAR THE
CONSENSUS MEAN THROUGH THE FORECAST PERIOD WITH HIGH CONFIDENCE.  

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