WDPN32 PGTW 182100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 25W (MAN-YI) WARNING NR 
040//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.5N 115.2E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 235 NM SOUTH-SOUTHEAST OF HONG KONG
   MOVEMENT PAST 6 HOURS: WESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 22 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS DEEP
CONVECTION RAPIDLY WANING OVER A LOW-LEVEL CIRCULATION (LLC)
EVIDENT IN A 181351Z METOP-C ASCAT PASS. THE INITIAL POSITION IS
PLACED WITH MEDIUM CONFIDENCE BASED ON RECENT MULTI-AGENCY
SATELLITE POSITION FIXES. THE INITIAL INTENSITY OF 50 KTS IS
ASSESSED WITH MEDIUM CONFIDENCE BASED ON A CONSENSUS OF SUBJECTIVE
DVORAK CURRENT INTENSITY AND AUTOMATED INTENSITY ESTIMATES. STORM
STRUCTURE HAS RAPIDLY DETERIORATED AS THE SYSTEM ENCOUNTERED A
LOW-LEVEL NORTHEASTERLY COLD SURGE ACROSS THE NORTHERN PORTION OF
THE SOUTH CHINA SEA AND INCREASED VERTICAL WIND SHEAR OVER THE PAST
SIX HOURS.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK AND 181351Z METOP-C
ASCAT PASS

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) EXTENSION TO
THE NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T4.0 - 65 KTS
   RCTP: T2.5 - 35 KTS
   KNES: T3.5 - 55 KTS
   DEMS: T4.0 - 65 KTS
   CIMSS SATCON: 50 KTS AT 181350Z
   CIMSS ADT: 51 KTS AT 181730Z
   CIMSS AIDT: 45 KTS AT 181730Z
   CIMSS D-PRINT: 34 KTS AT 181800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 20-25 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: STRONG POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: TS 25W WILL CONTINUE TO TRACK WESTWARD TO WEST-
SOUTHWESTWARD FOLLOWING THE PREVAILING LOW-LEVEL FLOW OVER THE SOUTH 
CHINA SEA AS THE CIRCULATION FULLY DECOUPLES FROM ASSOCIATED 
CONVECTION. PERSISTENT VERTICAL WIND SHEAR AND ENTRAINMENT OF DRIER 
AIR FROM THE WEST WILL DRIVE WEAKENING UNTIL THE SYSTEM DISSIPATES 
OVER WATER TO THE SOUTHEAST OF HAINAN ISLAND BY TAU 36 OR SOONER GIVEN 
THE HIGHLY UNFAVORABLE ENVIRONMENTAL CONDITIONS. THE REMNANT 
CIRCULATION IS NOT EXPECTED TO MAKE LANDFALL AT ANY POINT.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT
REGARDING THE OVERALL FORECAST SCENARIO, DIRECTION OF MOTION AND
INTENSITY FORECAST, INCLUDING DISSIPATION OF THE VORTEX. SPREAD IN
THE GUIDANCE PRIMARILY INVOLVES THE DISSIPATION TIMELINE. THE
CURRENT TRACK FORECAST LIES CLOSE TO THE PREVIOUS FORECAST AND
CURRENT MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE. THE INTENSITY
FORECAST IS SET SLIGHTLY BELOW THE INTENSITY CONSENSUS GIVEN
CURRENT AND ANTICIPATED HIGHLY UNFAVORABLE ENVIRONMENTAL
CONDITIONS.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   INTENSITY 0 - 72 HR: MEDIUM//
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