Advisories

WDPN31 PGTW 300900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 25W (SURIGAE) WARNING NR 
029//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 31.2N 138.3E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 256 NM SOUTH-SOUTHWEST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A
FULLY EXPOSED LOW-LEVEL CIRCULATION, WITH THE ONLY REMAINING
ASSOCIATED PATCH OF DEEP CONVECTION SHEARED TO THE EASTERN
PERIPHERY. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE
BASED ON THE EXPOSED CENTER AND RECENT SATELLITE FIXES FROM MULTIPLE
AGENCIES. THE INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH HIGH
CONFIDENCE BASED ON A CONSENSUS OF AVAILABLE SUBJECTIVE DVORAK AND
AUTOMATED INTENSITY ESTIMATES LISTED BELOW, WITH FURTHER SUPPORT
FROM A 300347Z OCEANSAT-3 PASS.

INITIAL WIND RADII BASIS: PERSISTENCE AND SCATTEROMETER DATA FROM A
300347Z OCEANSAT-3 PASS

CURRENT STEERING MECHANISM: LOW TO MID-LEVEL FLOW ASSOCIATED WITH A
DEEP-LAYER SUBTROPICAL RIDGE (STR) TO THE SOUTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T3.0 - 45 KTS
   RCTP: T2.0 - 30 KTS
   CIMSS SATCON: 35 KTS AT 300407Z
   CIMSS ADT: 25 KTS AT 300540Z
   CIMSS AIDT: 34 KTS AT 300540Z
   CIMSS D-MINT: 31 KTS AT 300408Z
   CIMSS D-PRINT: 29 KTS AT 300740Z

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

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TS 25W WILL ACCELERATE NORTHEASTWARD AND
COMPLETE EXTRATROPICAL TRANSITION DURING THE FORECAST PERIOD. THE
SYSTEM IS EXPECTED TO BEGIN MERGING WITH AN UPPER-LEVEL SHORTWAVE
TROUGH BY TAU 12, WHICH WILL INITIATE THE TRANSITION PROCESS. BY
TAU 24 THE SYSTEM WILL FULLY MERGE WITH THE TROUGH AND BECOME
EMBEDDED IN THE MID-LATITUDE WESTERLY FLOW PATTERN. TS 25W IS
EXPECTED TO MAINTAIN INTENSITY DUE TO STRONG DIVERGENT FLOW ALOFT
AND PASSAGE OVER WARM WATER FOR THE NEXT 12 HOURS AND HOLD STEADY
OR INCREASE SLIGHTLY IN INTENSITY THEREAFTER DUE TO FAVORABLE
BAROCLINIC SUPPORT. 

MODEL DISCUSSION: NUMERICAL MODEL TRACK AND INTENSITY FORECAST
GUIDANCE ARE IN VERY TIGHT AGREEMENT ON THE CURRENT CYCLE, BUT HAVE
SHIFTED SLIGHTLY POLEWARD FROM THE PREVIOUS CYCLE. THE TRACK
FORECAST IS CORRESPONDINGLY NUDGED POLEWARD AND IS CONSISTENT WITH
MULTI-MODEL CONSENSUS GUIDANCE WITH HIGH CONFIDENCE. MODELS AGREE
ON A GENERAL STEADY INTENSITY WITH THE POSSIBILITY OF SLIGHT
INTENSIFICATION DURING THE FORECAST PERIOD, AND THE CURRENT
FORECAST STAYS THE COURSE WITH HIGH CONFIDENCE.

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