Advisories

WDPN31 PGTW 281500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 25W (SURIGAE) WARNING NR 022//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 27.5N 132.8E
   INITIAL INTENSITY: 90 KTS
   GEOGRAPHIC REFERENCE: 586 NM SOUTHWEST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: EAST-NORTHEASTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 38 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TYPHOON 
(TY) 25W WITH PARTIALLY EXPOSED LOW-LEVEL BANDING ALONG THE WESTERN 
PERIPHERY IN RESPONSE TO THE HIGH (25-30 KTS) VERTICAL WIND SHEAR 
(VWS) THAT IS CONTINUING TO COMPRESS THE DEEP CONVECTION ON THE 
WESTERN EDGE AND SUPPRESS POLEWARD OUTFLOW. ENVIRONMENTAL ANALYSIS 
REVEALS A MARGINAL ENVIRONMENT DOMINATED BY HIGH VWS AND DRY AIR 
ENTRAINMENT, OFFSET SLIGHTLY BY THE MODERATE EQUATORWARD OUTFLOW AND 
WARM (28-29 C) SEA SURFACE TEMPERATURES. THE INITIAL POSITION IS 
PLACED WITH LOW CONFIDENCE BASED ON THE FULLY OBSCURED LOW LEVEL 
CIRCULATION CENTER AND PARTIALLY EXPOSED CLOUD BANDING. THE INITIAL 
INTENSITY OF 90 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE 
AGENCY DVORAK DATA-T FIXES RANGING FROM 4.5-5.5 (77-102 KTS) AND THE 
CIMSS AUTOMATED INTENSITY ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: THE WESTERN PERIPHERY OF THE DEEP-LAYER
SUBTROPICAL RIDGE (STR) POSITIONED TO THE EAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.0 - 115 KTS
   RJTD: T5.5 - 102 KTS
   RCTP: T5.5 - 102 KTS
   CIMSS ADT: 90 KTS AT 281140Z
   CIMSS AIDT: 83 KTS AT 281140Z
   CIMSS D-PRINT: 62 KTS AT 281140Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 25-30 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TY 25W (SURIGAE) IS FORECAST TO CONTINUE 
TRACKING GENERALLY NORTHEASTWARD FOR THE DURATION OF THE FORECAST 
PERIOD. 25W IS FORECAST TO MAINTAIN A RELATIVELY CONSISTENT TRACK 
SPEED UNTIL ABOUT TAU 36, AT WHICH POINT IT WILL BEGIN TO INTERACT 
WITH THE MID-LATITUDE WESTERLIES AND ACCELERATE POLEWARD. AS 25W 
TRACKS POLEWARD, IT WILL ENCOUNTER AN INCREASINGLY HOSTILE 
ENVIRONMENT CHARACTERIZED BY DRY AIR, INCREASING VWS, AND COOLING SEA 
SURFACE TEMPERATURES. 25W IS FORECAST TO BEGIN EXTRATROPICAL 
TRANSITION (ETT) BY TAU 60 AND COMPLETE TRANSITION NO LATER THAN TAU 
72. REGARDING INTENSITY, 25W IS EXPECTED TO RAPIDLY WEAKEN THROUGH 
TAU 24, FOLLOWED BY A MORE GRADUAL WEAKENING TREND FROM TAU 24-36 AS 
THE VWS ABATES SLIGHTLY. INTENSITY IS EXPECTED TO REMAIN RELATIVELY 
STABLE AS SURIGAE UNDERGOES ETT.

MODEL DISCUSSION: DETERMINISTIC MODEL TRACK GUIDANCE IS IN GOOD 
AGREEMENT IN CROSS-TRACK SPREAD AND IS IMPROVING IN ALONG-TRACK 
SPREAD. GFS IS THE MAJOR TRACK OUTLIER, DEPICTING A SIGNIFICANTLY 
SLOWER SPEED OF ADVANCE THROUGH TAU 72. DISREGARDING GFS, THE JTWC 
TRACK FORECAST IS PLACED WITH OVERALL MEDIUM CONFIDENCE. THE JTWC 
TRACK FORECAST REMAINS CONSISTENT AND IS BASED ON BOTH THE MULTI-
MODEL PHYSICS-BASED AND AI-BASED CONSENSUSES. RELIABLE INTENSITY 
GUIDANCE IS IN GOOD AGREEMENT ON AN INITIAL DRASTIC WEAKENING TREND, 
FOLLOWED BY A GRADUAL WEAKENING TREND, AND FINALLY A RELATIVELY 
STEADY INTENSITY AS 25W BECOMES EXTRATROPICAL. THE JTWC INTENSITY 
FORECAST IS IN CLOSE ALIGNMENT WITH THE MULTI-MODEL CONSENSUS AND IS 
ASSESSED WITH OVERALL MEDIUM CONFIDENCE.

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