WDPN32 PGTW 240300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (FRANCISCO) WARNING 
NR 008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 24.0N 128.0E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 150 NM SOUTH OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL STORM (TS) 10W REMAINS FIRMLY ENSCONCED WITHIN THE FAR
NORTHEASTERN EDGE OF A VERY LARGE, ELONGATED MONSOON GYRE, WITH A
DIAMETER OF APPROXIMATELY 1200NM AND A CENTROID OF ROTATION EAST OF
THE LUZON STRAIT. OVER THE PAST FEW HOURS, ANIMATED MULTISPECTRAL
SATELLITE IMAGERY (MSI) SHOWS A BURST OF DEEP CONVECTION FIRING IN
CLOSE PROXIMITY OF THE LOW LEVEL CIRCULATION CENTER (LLCC), BRIEFLY 
LEADING TO A TRACK WOBBLE NORTHWARD AS THE VORTEX TUCKED UNDER THE
CONVECTION. HOWEVER, THE OVERALL TRACK HAS REMAINED CONSISTENTLY 
NORTHWESTWARD OVER THE LAST COUPLE OF DAYS. WITH THE EXCEPTION OF 
THE CONVECTIVE BURST, WHICH IS ALREADY DISSIPATING, THE BULK OF THE 
CIRCULATION REMAINS EXPOSED DUE TO THE PRESENCE OF A DEEP LAYER 
OF DRY AIR OVERLAYING THE SYSTEM. A 232250Z SSMIS 91GHZ MICROWAVE 
IMAGE REVEALED A VERY SHALLOW VORTEX, DEVOID OF SIGNIFICANT 
CONVECTION WITH THE EXCEPTION OF THE SMALL BURST MENTIONED EARLIER. 
THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE 
MOSTLY EXPOSED LLCC, THE AFOREMENTIONED MICROWAVE IMAGE AND THE 
ANIMATED RADAR DATA OUT OF OKINAWA WHICH IS NOW PICKING UP THE 
SYSTEM ON THE FRINGES OF THE RADAR RANGE. THE INITIAL INTENSITY IS 
ASSESSED WITH MEDIUM CONFIDENCE, HEDGED TO THE HIGHER END OF THE 
SUBJECTIVE CURRENT INTENSITY ESTIMATES. ENVIRONMENTAL CONDITIONS 
REMAIN MARGINAL, WITH MODERATE SOUTHWESTERLY SHEAR AND DRY 
MID-LEVEL AIR OFFSETTING THE OTHERWISE FAVORABLE SST AND OUTFLOW 
CONDITIONS.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SYSTEM IS EMBEDDED WITHIN THE
NORTHEASTERN EDGE OF A BROAD MONSOON GYRE, STEERED ALONG THE TIGHT
GRADIENT FLOW BETWEEN THE GYRE CENTER AN AND A SUBTROPICAL RIDGE
(STR) TO THE NORTH. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T2.5 - 35 KTS
   KNES: T3.0 - 45 KTS
   CIMSS ADT: 33 KTS AT 240010Z
   CIMSS AIDT: 34 KTS AT 240010Z
   CIMSS D-MINT: 30 KTS AT 232250Z
   CIMSS D-PRINT: 30 KTS AT 240020Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: DRY MID-LEVEL AIR; BROAD NATURE OF THE
CIRCULATION. 

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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 10W IS FORECAST TO CONTINUE TRACKING
NORTHWESTWARD ALONG THE GRADIENT BETWEEN THE STR TO THE NORTH AND
THE MONSOON GYRE. NEAR-TERM MOTION HAS SHIFTED A BIT NORTHWARD,
WITH THE VORTEX DRAWN TOWARDS THE RECENT CONVECTIVE BURST, HOWEVER
IT IS EXPECTED THE VORTEX WILL RESUME ITS NORTHWESTWARD TRACK
SHORTLY. HOWEVER, THE WIND FIELD REMAINS QUITE LARGE, EXTENDING UP
TO 165NM OUTWARD FROM THE CENTER, PARTICULARLY IN THE NORTHEASTERN
QUADRANT. THE SYSTEM IS FORECAST TO PASS SOUTH OF OKINAWA WITHIN
THE NEXT 12 HOURS, AND QUICKLY MOVE INTO THE EAST CHINA SEA. AS IT
DOES SO, THE VORTEX IS EXPECTED TO OPEN UP AND ELONGATE, AS IT
MERGES WITH AND ULTIMATELY IS ABSORBED WITHIN THE MONSOON GYRE. THE
SYSTEM IS FORECAST TO MAINTAIN ITS CURRENT INTENSITY AS IT PASSES
SOUTH OF OKINAWA, BUT THEN QUICKLY WEAKEN AS IT MOVES INTO THE
SOUTH CHINA SEA AS IT IS ENGULFED BY MID-LEVEL DRY AIR AND SHEARED
APART BY MODERATE TO STRONG EASTERLY SHEAR. BY TAU 36, THE SYSTEM
IS FORECAST TO DISSIPATE AS A DISCRETE TROPICAL CYCLONE AS IT IS
ABSORBED INTO THE MONSOON GYRE. HOWEVER, ELEVATED WINDS OF 30
KNOTS, ASSOCIATED WITH THE PERIPHERY OF THE MONSOON GYRE FLOW, WILL
STILL BE PRESENT IN FAVORED AREAS, PRIMARILY ISOLATED TO THE COAST
OF EASTERN CHINA AND THE NORTHERN TAIWAN STRAIT. 

MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE IS IN GOOD AGREEMENT
THROUGH THE FORECAST PERIOD. THE JTWC FORECAST IS POSITIONED ON THE
NORTHERN EDGE OF THE GUIDANCE ENVELOPE THROUGH THE FORECAST PERIOD,
TRACKING THE VORTICITY MAXIMUM IN THE FAR NORTHEASTERN EXTENT OF
THE MONSOON GYRE AND HEAVILY FAVORS THE ECMWF AND EC-AIFS TRACKERS.
THE JTWC FORECAST REMAINS CONSISTENT WITH PREVIOUS FORECASTS,
HOWEVER THE TRACK THE CPA TO OKINAWA HAS DECREASED BY ABOUT 25NM
DUE TO THE RECENT VORTEX WOBBLE. NO CHANGE TO WINDS OR IMPACTS
ACROSS OKINAWA ARE EXPECTED REGARDLESS OF THE CHANGE IN CPA. DUE TO
THE BROAD NATURE OF THE SYSTEM AND THE FORECASTED EVOLUTION AS IT 
PASSES THROUGH THE RYUKUS, SHIFTS IN THE INITIAL POSITION AND TRACK 
ARE VERY LIKELY. INTENSITY GUIDANCE REMAINS IN GOOD AGREEMENT THAT THE 
SYSTEM WILL MAINTAIN ITS CURRENT INTENSITY AS IT PASSES OKINAWA AND 
THEN QUICKLY WEAKEN ONCE IT MOVES INTO THE EAST CHINA SEA. 

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