WDPN31 PGTW 251500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 07W (MEKKHALA) WARNING NR 
028//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 25.5N 126.2E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 105 NM SOUTHWEST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
STORM (TS) 07W INCREASINGLY SHEARED WITH THE DEEP CONVECTION
DISPLACED FAR TO THE SOUTHEAST. THE PARTIAL 251202Z METOP-B ASCAT
DATA REVEALED THE STRONGEST WIND SPEEDS IN THE SWATH ARE CONFINED TO 
THE SOUTHWESTERN QUADRANT. ADDITIONALLY, SURFACE OBSERVATION STATIONS 
FROM NAHA AND KUMEJIMA ARE REPORTING MAXIMUM 23KT SOUTHEASTERLY WINDS, 
HOWEVER, THE STORM IS STILL APPROXIMATELY 100 NM AWAY FROM BOTH 
STATIONS. ENVIRONMENTAL ANALYSIS REVEALS AN UNFAVORABLE ENVIRONMENT 
CHARACTERIZED BY THE VWS, MODERATE OUTFLOW, AND DRY AIR ENTRAINMENT IN 
THE NORTHERN HEMISPHERE, MARGINALLY OFFSET, BUT THE WARM (27-28 C) SEA 
SURFACE TEMPERATURES. THE INITIAL POSITION AND INTENSITY ARE PLACED 
WITH HIGH CONFIDENCE BASED ON THE AFOREMENTIONED 251202Z ASCAT DATA.

INITIAL WIND RADII BASIS: ADJUSTED THE WESTERN SEMICIRCLE BASED ON
THE 251202Z METOP-B ASCAT DATA

CURRENT STEERING MECHANISM: THE WESTERN PERIPHERY OF THE
SUBTROPICAL RIDGE (STR) CENTERED TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T2.5 - 35 KTS
   KNES: T3.0 - 45 KTS
   CIMSS ADT: 47 KTS AT 251300Z
   CIMSS AIDT: 43 KTS AT 251300Z
   CIMSS D-PRINT: 36 KTS AT 251300Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 15-20 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

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 07W IS FORECAST TO CONTINUE ROUNDING THE
STEERING STR CENTERED TO THE EAST AND ACCELERATE NORTHEASTWARD.
MEKKHALA IS EXPECTED TO REACH ITS CLOSEST POINT TO OKINAWA JUST
BEFORE TAU 12, BEFORE TRACKING ALONG THE SOUTHERN COAST OF MAINLAND
JAPAN. AT AROUND TAU 24, 07W WILL ENCOUNTER HIGH (30-35 KTS) VWS
ASSOCIATED WITH THE UPPER-LEVEL WESTERLIES AND SIGNIFICANT DRY AIR
ENTRAINMENT, SHALLOWING THE VORTEX, AND INDUCING EXTRATROPICAL
TRANSITION (ETT). MEKKHALA IS FORECAST TO COMPLETE ETT BY
TAU 48 AS THE STORM PASSES SOUTH OF TOKYO. REGARDING INTENSITY, 07W
IS FORECAST TO GRADUALLY WEAKEN FROM TAU 0 THROUGH THE END OF THE
FORECAST PERIOD AT TAU 48. DESPITE THE HOSTILE ENVIRONMENT, 07W
WILL LIKELY MAINTAIN ITS INTENSITY FAIRLY WELL AS IT UNDERGOES AND
COMPLETES ETT, MAINTAINING GALE FORCE WINDS THROUGH TAU 48.

MODEL DISCUSSION: DETERMINISTIC MODEL TRACK GUIDANCE REMAINS IN
SOLID AGREEMENT THROUGHOUT THE DURATION OF THE FORECAST PERIOD.
THERE IS SLIGHT DISAGREEMENT AMONG MODELS AS 07W IS FORECAST TO
ACCELERATE NORTHEASTWARD, CAUSING MINOR ALONG-TRACK DISCREPANCIES.
THE AI-BASED AND PHYSICS-BASED ECMWF DETERMINISTIC AND ENSEMBLE
TRACKERS REMAIN FASTER THAN OTHER MODELS, BUT THE PREVIOUSLY NOTED
DIFFERENCE HAS SIGNIFICANTLY DECREASED. AS A RESULT, THE JTWC TRACK
FORECAST IS PLACED WITH OVERALL HIGH CONFIDENCE. RELIABLE INTENSITY
AIDS ARE IN GENERAL AGREEMENT THAT 07W WILL GRADUALLY WEAKEN
THROUGH TAU 48, THOUGH THE MESOSCALE MODELS ARE DEPICTING A
SLIGHTLY FASTER RATE OF DECAY. THE JTWC INTENSITY FORECAST LIES
VERY CLOSE TO THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE. 

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