WDPN31 PGTW 110300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 03W (GUCHOL) WARNING NR 021//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 23.2N 131.6E
   INITIAL INTENSITY: 85 KTS
   GEOGRAPHIC REFERENCE: 286 NM SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 14 KTS
   SIGNIFICANT WAVE HEIGHT: 38 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS AN
ASYMMETRIC AND RAGGED CENTRAL DENSE OVERCAST (CDO) FEATURE,
DISPLACED PRIMARILY TO THE NORTHEAST OF THE CIRCULATION. THE LOW
LEVEL CIRCULATION CENTER (LLCC) IS OBSCURED BUT EXTRAPOLATION OF A
MICROWAVE EYE FEATURE IN A 102126Z SSMIS 37GHZ IMAGE AND A LARGE
35NM EYE IN A 102113Z RCM-2 SAR PASS PROVIDED HIGH CONFIDENCE IN
THE INITIAL POSITION. BOTH THE MICROWAVE AND THE SAR PASS ALSO
SHOWED THAT THE LOW-LEVEL STRUCTURE REMAINS INTACT AND ROBUST ON
THE EASTERN FLANK OF THE CIRCULATION, WHILE THE NORTHWEST QUADRANT
IN PARTICULAR HAS CONTINUED TO BE ERODED BY THE PERSISTENT
NORTHWESTERLY SHEAR. RECEIPT OF THE SAR DATA SUPPORTS A SLIGHTLY
HIGHER INTENSITY THAN THE DVORAK TECHNIQUES WOULD OTHERWISE
SUGGEST, WITH THE MAXIMUM WINDS MEASURED BY THE SAR OF 95 KNOTS IN
A SMALL PATCH IN THE NORTHEAST SECTOR, EMBEDDED WITHIN A MUCH
LARGER REGION OF WINDS BETWEEN 75-90 KNOTS. THE OVERALL INTENSITY
IS ESTIMATED TO BE 85 KNOTS, WHICH IS ALSO IN FAIRLY GOOD AGREEMENT
WITH AN EARLIER SATCON ESTIMATE, BUT SIGNIFICANTLY HIGHER THAN THE
AGENCY AND OBJECTIVE DVORAK ESTIMATES. THE SYSTEM IS FEELING THE
IMPACT OF THE PERSISTENT NORTHWESTERLY SHEAR, AND A REGION OF DRY
MID-LEVEL AIR SITTING TO THE NORTH OF THE CIRCULATION. THE SYSTEM
IS CURRENTLY RIDING UP THE NORTHWEST PERIPHERY OF THE NEAR
EQUATORIAL RIDGE (NER) POSITIONED TO THE SOUTHEAST.

INITIAL WIND RADII BASIS: SAR DATA 

CURRENT STEERING MECHANISM: NORTHWEST PERIPHERY OF A DEEP-LAYER NER
TO THE SOUTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T4.0 - 65 KTS
   KNES: T4.0 - 65 KTS
   CIMSS SATCON: 89 KTS AT 101654Z
   CIMSS ADT: 77 KTS AT 110000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 15-20 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE EASTWARD
   OTHER FACTORS: DRY MID-LEVEL AIR TO THE NORTH. DEVELOPING
POLEWARD OUTFLOW CHANNEL.

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: NO SIGNIFICANT CHANGE IN THE FORECAST TRACK IS
ANTICIPATED, AS THE SYSTEM WILL CONTINUE TO RIDE UP THE NORTHWEST
SIDE OF NER FOR ANOTHER 12 TO 24 HOURS. AFTER TAU 24 THE PRIMARY
STEERING INFLUENCE WILL SHIFT TO THE LARGE DEEP-LAYER SUBTROPICAL
RIDGE (STR) CENTERED FAR TO THE EAST. BUT THE OVERALL STORM
TRAJECTORY IS NOT EXPECTED TO CHANGE MUCH, FOLLOWING A GENERAL
NORTHEASTWARD TRACK THROUGH THE FORECAST PERIOD. EVEN THOUGH THE
SHEAR AND DRY AIR ARE BEGINNING TO ERODE THE NORTHWEST SIDE OF THE
CIRCULATION, IT HAS NOT YET PUNCHED INTO THE INNER CORE, AT LEAST
NOT IN THE LOW-LEVELS AND THUS THE INTENSITY IS ONLY VERY SLOWLY
STARTING TO COME DOWN FROM THE EARLIER PEAK. THE LATEST CIMSS AMV
ANALYSIS SUGGESTS THAT THE SHEAR MAY BE LESSENING JUST A TAD, AND
AT THE SAME TIME SOME TENTATIVE FINGERS OF OUTFLOW ARE STRETCHING
OUT TOWARDS A 200MB JET STREAK OVER SOUTHERN JAPAN. GLOBAL MODEL
FIELDS SUGGEST IMPROVING POLEWARD OUTFLOW GOING FORWARD AS THE
SYSTEM NEARS THE JET STREAM OVER JAPAN. THIS WILL SET UP A CONFLICT
BETWEEN INCREASING OUTFLOW AND INCREASING SHEAR, AS WELL AS
DECREASING SSTS. THE NET EFFECT WILL BE A RATHER SLOW WEAKENING FOR
THE NEXT 24 HOURS.  BUT THEN THE SHEAR WILL TAKE OVER, DECAPITATE
THE VORTEX AND AS THE SYSTEM MOVES NORTH OF THE 26C ISOTHERM, IT
WILL BEGIN SUBTROPICAL TRANSITION (STT). TRANSITION TO A
SUBTROPICAL LOW IS EXPECTED BY TAU 36 BUT WILL BE SHORT-LIVED, AS
THE SYSTEM WILL RAPIDLY MOVE INTO EXTRATROPICAL TRANSITION (ETT) AS
IT RACES NORTHEAST AT OVER 20 KNOTS, STARTS TO DEVELOP THERMAL
ADVECTION AND FRONTAL CHARACTERISTICS AND BECOMES EMBEDDED UNDER
THE STRONG MID-LATITUDE WESTERLIES. TRANSITION TO A GALE-FORCE
EXTRATROPICAL LOW IS ANTICIPATED NO LATER THAN TAU 72, AND
POTENTIALLY AS EARLY AS TAU 60. 

MODEL DISCUSSION: TRACK GUIDANCE IS IN VERY TIGHT AGREEMENT, WITH
LITTLE IN THE WAY OF CROSS- OR ALONG-TRACK SPREAD THROUGH THE
FORECAST. INTENSITY GUIDANCE IS ALSO IN GOOD AGREEMENT, WITH ALL
CONSENSUS MEMBERS AGREEING ON GENERALLY SLOW WEAKENING THROUGH TAU
24, FOLLOWED BY MORE STEADY AND RAPID WEAKENING THROUGH THE
REMAINDER OF THE FORECAST. 

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