WDPN31 PGTW 300900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 02W (MAWAR) WARNING NR 042//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.5N 125.0E
   INITIAL INTENSITY: 75 KTS
   GEOGRAPHIC REFERENCE: 392 NM SOUTH-SOUTHWEST OF KADENA AB,
OKINAWA
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 02 KTS
   SIGNIFICANT WAVE HEIGHT: 32 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TYPHOON (TY) 02W HAS WEAKENED RAPIDLY (35 KNOTS) OVER THE PAST DAY
DECREASING FROM 110 KNOTS AT 290600Z TO THE CURRENT INTENSITY OF 75
KNOTS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS
RAPID DECAY OF THE CONVECTIVE CORE, INCLUDING THE LOSS OF THE EYE,
AND DETERIORATING CONVECTIVE BANDING. ALTHOUGH NOT STRONGLY
INDICATED IN THE UW-CIMSS M-PERC PRODUCT, RECENT MICROWAVE IMAGERY
SUGGESTS A WEAK EYEWALL REPLACEMENT CYCLE (ERC) WITH A STEADILY
DECAYING INNER EYEWALL SURROUNDED BY A NARROW, FRAGMENTED OUTER
EYEWALL. A 300710Z SSMIS 91GHZ COLOR COMPOSITE MICROWAVE IMAGE NOW
SHOWS NO INNER EYEWALL WITH ERODED SPIRAL BANDING OVER THE NORTHERN
AND NORTHWESTERN QUADRANTS. THERE IS HIGH CONFIDENCE IN THE INITIAL
POSITION BASED ON THE SSMIS IMAGE AND AN EARLIER 300523Z GMI 89GHZ
COLOR COMPOSITE MICROWAVE IMAGE SHOWING A WELL-DEFINED CENTER WITH
A PARTIAL EYEWALL. ENVIRONMENTAL CONDITIONS ARE MARGINAL DUE TO THE
UPWELLING OF COOLER WATER AND THE PRESENCE OF COOLER WATER (25-26C)
OVER THE EASTERN AND NORTHERN QUADRANTS. ADDITIONALLY, THE ONGOING
ERC IS CONTRIBUTING TO RAPID WEAKENING OF THE CORE. THE INITIAL
INTENSITY IS ASSESSED AT 75 KNOTS WITH MEDIUM CONFIDENCE BASED ON
AN AVERAGE OF THE DVORAK CURRENT INTENSITY ESTIMATES AND THE ADT
ESTIMATE.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: COMPETING STEERING PATTERN WITH A
DEEP-LAYER SUBTROPICAL RIDGE (STR) POSITIONED TO THE EAST AND
ANOTHER STR ENTRENCHED OVER SOUTHEAST CHINA. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T5.0 - 90 KTS
   KNES: T4.5 - 77 KTS
   CIMSS SATCON: 92 KTS AT 300432Z
   CIMSS ADT: 74 KTS AT 300220Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE RADIAL
   OTHER FACTORS: COOL UPWELLING WATER

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TY 02W IS EMBEDDED WITHIN A COMPETING STEERING
PATTERN WITH ZONAL 500MB FLOW PREVAILING TO THE NORTH OVER THE
KOREAN PENINSULA AND JAPAN. CONSEQUENTLY, THE SYSTEM HAS SLOWED AND
IS DRIFTING SLOWLY POLEWARD. DUE TO THE LACK OF A DYNAMIC
MIDLATITUDE SHORTWAVE TROUGH TO ACCELERATE THE SYSTEM POLEWARD
THROUGH TAU 72, TRACK SPEEDS ARE EXPECTED TO REMAIN
CLIMATOLOGICALLY SLOW (LESS THAN 7 KNOTS). TY 02W IS EXPECTED TO 
STEADILY WEAKEN THROUGH TAU 72 WITH COOLING SST AND DRY AIR 
ENTRAINMENT. AFTER TAU 72, AN APPROACHING MIDLATITUDE TROUGH WILL DIG 
TO THE NORTH ALLOWING THE SYSTEM TO GRADUALLY RECURVE AND ACCELERATE 
INTO THE SUBTROPICAL WESTERLIES. MORE SIGNIFICANT WEAKENING IS 
ANTICIPATED WITH COOLER SST (23-24C), DRY AIR ENTRAINMENT AND 
INCREASING VERTICAL WIND SHEAR. AFTER A SHORT PERIOD OF SUBTROPICAL 
TRANSITION, TY 02W IS EXPECTED TO UNDERGO EXTRA-TROPICAL TRANSITION 
AS IT APPROACHES THE KANTO PLAIN AFTER DAY 5.          

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE REMAINS IN GOOD
CROSS-TRACK AGREEMENT WITH AN 80-100NM SPREAD IN SOLUTIONS THROUGH 
THE FORECAST PERIOD. HOWEVER, THERE IS A SIGNIFICANT, GROWING 
DIFFERENCE IN ALONG-TRACK SPEEDS WITH NAVGEM SLOWING TO A CRAWL AND 
THE JGSM RAPIDLY ACCELERATING NORTHEASTWARD. THE 300000Z ECMWF (EPS) 
AND GFS (GEFS) PROBABILISTIC GUIDANCE INDICATES A SIMILAR SPREAD OF 
GUIDANCE. OVERALL, THERE IS MEDIUM CONFIDENCE THROUGH DAY 3 AND LOW 
CONFIDENCE AFTER DAY 3. IT IS WORTH NOTING THAT BOTH DETERMINISTIC 
AND PROBABILISTIC GUIDANCE INDICATE POTENTIAL FOR THE SYSTEM TO TRACK 
OVER OKINAWA, AND REGARDLESS OF THE TRACK OVER OR TO THE EAST OF 
OKINAWA, THE SYSTEM IS STILL EXPECTED TO PRODUCE STORM-FORCE WINDS AS 
IT TRACKS NEAR THE RYUKYU ISLAND CHAIN.    

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