WDPN31 PGTW 030900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W (HINNAMNOR) 
WARNING NR 025//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 23.7N 124.7E
   INITIAL INTENSITY: 85 KTS
   GEOGRAPHIC REFERENCE: 238 NM SOUTHWEST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 42 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A WELL
DEFINED CIRCULATION THAT IS ON THE VERGE OF REDEVELOPING AN EYE.
ANIMATED RADAR IMAGERY AND A 030523Z AMSR2 89GHZ COLOR COMPOSITE
MICROWAVE IMAGE INDICATE THE SYSTEM IS CONTINUING TO CONSOLIDATE
AFTER ITS SLOW NORTHWARD CRAWL OVER THE PAST TWO DAYS. THE AMSR2
IMAGE INDICATING THAT THE SYSTEM IS STILL COMBATING DRY AIR ON ITS
NORTHWESTERN PERIPHERY, NEVERTHELESS A NEARLY COMPLETE EYE WALL IS
EVIDENT. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED
ON MSI, RADAR IMAGERY AND THE AMSR2 MICROWAVE IMAGERY. THE INITIAL
INTENSITY OF 85 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON
AGENCY DVORAK ESTIMATES REMAINING LOW 75-77KTS, DUE TO NO CLEAR EYE
FEATURE, WHILE CIMSS SATCON AND ADT INDICATE 89-94KTS. THIS REGION
OF DVORAK INTENSITY AND METHOD SHIFT FROM WRAPPING TO EYE METHOD IS
NOTORIOUSLY TRICKY. FOR EXAMPLE IF THE EYE CLEARS (CLOUD TOPS
WARMING) FROM IT CURRENT -43C TO BELOW -41C (A TWO DEGREE DROP) AND
THE EYE WALL CONTINUES TO DEVELOP THE DVORAK RETURNS AN EYE METHOD
T5.0, SO WE ARE CLOSE.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP SUBTROPICAL
RIDGE (STR) TO THE EAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T5.0 - 90 KTS
   KNES: T4.5 - 77 KTS
   CIMSS SATCON: 89 KTS AT 030424Z
   CIMSS ADT: 94 KTS AT 030540Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: STRONG RADIAL

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 12W IS CURRENTLY TRACKING NORTH-NORTHWEST
UNDER THE STEERING INFLUENCE OF A STR TO THE EAST. AS THE SYSTEM
CONTINUES TO TRACK GENERALLY NORTHWARD IT WILL PASS JUST EAST OF
ISHIKAGIJIMA BEFORE ENTERING THE EAST CHINA SEA. THE SYSTEM IS
BATTLING SUBSIDENCE ALOFT AND INHIBITED OUTFLOW ON ITS WESTERN
FLANK DUE TO A DEEP LAYERED STR BRINGING NORTHERLY DRY AIR
SOUTHWARD, HOWEVER AS THE SYSTEM PROGRESSES NORTHWARD THIS
INTERACTION WILL DECREASE AND INTENSITIES WILL RISE. BY TAU 36, THE
SYSTEM WILL REACH ITS PEAK NEAR 110KTS AS IT BRIEFLY TAPS INTO A
GOOD POLEWARD OUTFLOW CHANNEL WHICH IS THE HERALD OF ITS IMPEDING
EXTRATROPICAL TRANSITION. BY TAU 48, TY 12W WILL BE TRACKING
NORTH-NORTHEASTWARD AS ITS STEERING RIDGE REORIENTS DUE TO A STRONG
MID-LATITUDE TROUGH APPROACHING FROM THE WEST, THIS INTERACTION
WILL ALSO GREATLY INCREASE TRACK SPEEDS. AS THIS TROUGH DIGS DOWN
OVER THE KOREAN PENINSULA, 12W WILL EXPERIENCE DRAMATICALLY MORE
SHEAR AND WILL BEGIN TO INTERACT WITH THE PENINSULA ITSELF FURTHER
WEAKENING THE SYSTEM. AS 12W CROSSES SOUTHERN COAST OF KOREA JUST
BEFORE TAU 72, IT INTERACTS WITH AND INCORPORATES INTO THE
MID-LATITUDE WESTERLY FLOW ALOFT AND BEGIN EXTRA-TROPICAL
TRANSITION. BY TAU 96 THE SYSTEM WILL COMPLETE EXTRATROPICAL
TRANSITION IN THE NORTHERN SEA OF JAPAN.

MODEL DISCUSSION: WITH THE EXCEPTION OF COAMPS-TC, NUMERICAL MODELS
ARE IN TIGHT AGREEMENT THAT 12W WILL CONTINUE ITS GENERALLY
NORTHWARD TREND BEFORE A NORTHEASTERLY RECURVE NEAR TAU 48 AND A
FINAL RAPID ACCELERATION TOWARD THE NORTHEASTERN SEA OF JAPAN.
AFTER PASSING THE KOREAN PENINSULA, THERE IS A NOTABLE CROSS TRACK
SPREADING THROUGH THE FORECAST PERIOD. FOR THESE REASONS THE
CURRENT JTWC TRACK FORECAST IS PLACED WITH HIGH CONFIDENCE AND THE
EXTENDED TRACK FORECAST IS PLACED WITH LOW CONFIDENCE. RELIABLE
MODEL INTENSITY GUIDANCE IS IN FAIR AGREEMENT WITH A BULK OF THE
MODELS SHOWING A GENERAL INTENSIFICATION TREND THROUGH 36 WHILE
HWRF AND DECAY-SHIPS (NAVGEM) INDICATE STAGNATION AND DISSIPATION
PAST TAU 12. THIS DISCREPANCY IN INTENSIFICATION TREND IS WHY THE
JTWC FORECAST INTENSITY IS PLACED WITH MEDIUM CONFIDENCE.

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