WDPN32 PGTW 192100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 05W (GAEMI) WARNING 
NR 005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.7N 126.1E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 596 NM SOUTH OF KADENA AB
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL STORM 05W (GAEMI) GATHERED SOME STRENGTH AND CAME INTO
BETTER ALIGNMENT OVER THE PAST SIX HOURS. A 201503 GMI 37H IMAGE
SHOWS A TIGHT OPEN CENTER SURROUNDED BY TIGHTLY CURVED BANDS OF
DEEP CONVECTION ON ALMOST ALL QUADRANTS. A 201300Z ASCATB PASS VERY
NEAR THE RJTD FIX GIVES A CONFIDENT ASSESSMENT ON THE SYSTEM
POSITION AND INTENSITY AS WELL AS REVEALING ITS INHERENT ASYMMETRY.
GALE FORCE WINDS EXTEND OVER MUCH OF THE NORTHWESTERN QUADRANT AND
INTO THE SOUTHWESTERN QUADRANT. CONVECTION IS SURGING DURING THIS
DIURNAL MAXIMUM PERIOD BUT IS STILL BEING SHEARED TO THE WSW BY
17KTS OF VERTICAL WINDSHEAR (VWS). THE ARE HOWEVER INDICATIONS THAT
THE CONVECTION IS CONSOLIDATING CLOSER TO THE CORE AND THE SYSTEM
IS BECOMING MORE VERTICALLY STACKED. THERE HAS BEEN A SLIGHT
WESTWARD JOG IN TRACK BUT THAT MAY BE AN AFFECT OF A RATHER
SPECTACULAR SURGE OF DEEP CONVECTION IN THE SOUTHWEST QUADRANT.
OUTFLOW REMAINS EXCELLENT PARTICULARLY OVER THE POLEWARD SEMICIRCLE
BUT THE CHANNEL TOWARDS A DEEP TUTT CELL OVER THE NORTHERN MARIANAS
IS BECOMING STRETCHED AS SEPARATION INCREASES.

INITIAL WIND RADII BASIS: A 201300Z ASCATB PASS.

CURRENT STEERING MECHANISM: THE SOUTHEASTERN PERIPHERY OF THE
SUBTROPICAL RIDGE, WHICH IS CURRENTLY ANCHORED IN AN ANTICYCLONE TO
THE EAST-SOUTHEAST OF SHIKOKU. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T2.5 - 35 KTS
   KNES: T3.0 - 45 KTS
   CIMSS SATCON: 40 KTS AT 1730Z
   CIMSS ADT: 37 KTS AT 1930ZZ

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 17 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE EXTENDED RANGE TRACK HAS SHIFTED
TO A LANDFALL SOUTH OF SHANGHAI RATHER THAN A GRAZE OFF-SHORE OF
SHANGHAI, WHICH RESULTS IN A PRECIPITOUS DROP IN INTENSITY IN THE
LONG RANGE. THE MID RANGE FORECAST HAS SHIFTED SOUTHWARD RESULTING
IN A LOWER THREAT TO OKINAWA. 

FORECAST DISCUSSION: THE RECENT JOG TO THE WEST COUPLED WITH THE
LATEST GUIDANCE PACKAGE HAS RESULTED IN A SIGNIFICANT TRACK
EQUATORWARD SHIFT IN THE TRACK. RATHER THAN TRACKING BETWEEN
ISHIGAKI JIMA AND MIYAKO JIMA THE SYSTEM WILL TRACK THROUGH THE
SOUTHERN SENKAKUS ON ITS WAY TO THE EAST CHINA SEA.  THIS RAISES
THE THREAT OF GALE FORCE WINDS TO TAIWAN WHILE REDUCING IT TO
OKINAWA.  THE DEGREE TO WHICH THE SYSTEM IS INFLUENCED DEPENDS ON
THE INTERACTION BETWEEN A QUASI-STATIONARY UPPER LEVEL ANTICYCLONE
JUST SOUTH OF JAPAN WITH AN APPROACHING UNSEASONABLY DEEP AND
VIGOROUS SHORT WAVE TROF THAT IS CURRENTLY APPROACHING SHANGHAI.
RECENT GUIDANCE INDICATES THE OCEANIC RIDGE WILL FEND OFF THE TROF
AND NOT ALLOW THE SYSTEM TO BEND POLEWARD OVER THE EAST CHINA SEA,
FORCING IT SOUTH OF SHANGHAI.  THE SEASON AND H500 HEIGHTS OVER
TOKYO EXCEEDING 590DM SUPPORT THE SCENARIO OF THE SYSTEM BEING
FORCED INLAND SOUTH OF SHANGHAI AND SPARING THE CENTRAL RYUKUS.
EACH BEARING OVER THE NEXT 36 HOURS WILL EITHER INCREASE OR
DECREASE THE CERTAINTY OF THAT SCENARIO. 

MODEL DISCUSSION: THE MODEL GUIDANCE HAS NOT FUNDAMENTALLY CHANGED
BUT THE EQUATORWARD SHIFT HAS LARGE IMPACTS TO BOTH TAIWAN AND THE
RYUKUS.  THE JTWC TRACK FORECAST STAYS POLEWARD OF THE MULTI-MODEL
CONSENSUS AND EQUATORWARD OF THE AMERICAN MODEL CONSENSUS, WALKING
A LITTLE EQUATORWARD OF THE PREVIOUS TRACK. THE INTENSITY FORECAST
REMAINS SIMILAR THROUGH THE SENKAKU PASSAGE, BUT DEVIATES MUCH
LOWER AT THE END DUE TO THE EXPECTATION OF LANDFALL.
 


FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: LOW
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: LOW//
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