WDPN32 PGTW 250300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 05W (GAEMI) WARNING NR 022//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 25.1N 120.2E
   INITIAL INTENSITY: 75 KTS
   GEOGRAPHIC REFERENCE: 71 NM WEST OF TAIPEI, TAIWAN
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 26 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) AS WELL AS ANIMATED
CENTRAL WEATHER ADMINISTRATION (CWA) RADAR DATA SHOW THAT THE
VORTEX OF TYPHOON (TY) 05W (GAEMI) HAS CROSSED OR JUMPED ACROSS THE
NORTHERN PORTION OF TAIWAN AND REFORMED, AT LEAST IN THE
MID-LEVELS, OF THE WESTERN COAST OF TAIWAN OVER THE PAST SIX HOURS.
THE INFLUENCE OF THE PASSAGE OVER THE EXTREMELY RUGGED TERRAIN HAS
DONE A NUMBER OF THE VORTEX STRUCTURE, EFFECTIVELY KNEECAPPING IT,
THE MID- AND UPPER-LEVEL VORTEX MOVING SWIFTLY OFF TO THE WEST
WHILE THE REMNANTS OF THE INITIAL LOW-LEVEL VORTEX HAVE REMAIN
STUCK OVER LAND OR COMPLETELY ERODED AWAY. RADAR DATA SUGGESTS A
VERY COMPACT INNER CORE SURROUNDED BY A MOAT FEATURE AND SPIRAL
CONVECTIVE BANDS WRAPPING INTO THE CORE PRIMARILY FROM THE EAST AND
NORTH, WHILE THE CORE IS SEPARATED FROM THE BANDING FEATURES IN THE
SOUTHERN PORTIONS DUE TO TERRAIN INTERFERENCE. THE INITIAL POSITION
IS ASSESSED WITH HIGH CONFIDENCE, THOUGH IN REALITY IT MAY BE MORE
OF THE MID-LEVEL ROTATION THAT'S SEEN IN THE RADAR DATA. THE
INITIAL INTENSITY IS ASSESSED AT 75 KNOTS WITH MEDIUM CONFIDENCE
BASED ON THE ADT ESTIMATE OF 72 KNOTS AND THE AGENCY T4.5 CURRENT
INTENSITY ESTIMATES, THOUGH IT IS ACKNOWLEDGED THIS VALUE COULD BE
A BIT HIGH. THE SYSTEM IS MOVING THROUGH A MARGINALLY UNFAVORABLE
ENVIRONMENT CHARACTERIZED BY WEAK RADIAL OUTFLOW WITH AN ENHANCED
EQUATORWARD OUTFLOW CHANNEL INTO THE EASTERN PORTIONS OF THE
TROPICAL EASTERLY JET (TEJ) AND WARM SSTS OFFSET BY MODERATE TO
HIGH NORTHERLY WIND SHEAR AND LAND INTERACTION.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED TO THE NORTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T4.5 - 77 KTS
   RCTP: T4.5 - 77 KTS
   KNES: T3.0 - 45 KTS
   CIMSS ADT: 72 KTS AT 250030Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 20-25 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE RADIAL
   OTHER FACTORS: LAND INTERACTION.

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: AFTER MAKING A QUICK DASH ACROSS TAIWAN AND
BEING KNEECAPPED, TY 05W HAS MOVED INTO THE TAIWAN STRAIT, MAKING
ITS WAY TOWARDS A SECOND LANDFALL IN MAINLAND CHINA. THE OVERALL
TRACK MOTION IS FORECAST TO BE ALMOST DUE WEST FOR THE FIRST FEW
HOURS, UP UNTIL LANDFALL. THIS IS BACKED UP BY THE MOST RECENT
RADAR DATA SUGGESTING A DUE WEST TRACK. LANDFALL IS EXPECTED WITHIN
THE NEXT FEW HOURS TO THE NORTHEAST OF QUANZHOU, CHINA. THEREAFTER
THE SYSTEM WILL MOVE INLAND FOR THE REMAINDER OF THE FORECAST
PERIOD, ALONG THE SOUTHWESTERN SIDE OF THE STEERING RIDGE TO THE
EAST, TOWARDS A BREAK IN THE RIDGE INDUCED BY THE PASSAGE OF A
MID-LATITUDE TROUGH TO THE NORTH. HAVING BEEN SIGNIFICANTLY
WEAKENED AND THE VORTEX SHREDDED AFTER PASSAGE OVER TAIWAN, THE
LIMITED AMOUNT TIME LEFT OVER WATER NOW BECOMES THE PRIMARY
LIMITING FACTOR FOR TY 05W. THE VORTEX IS BUILDING BACK DOWN TO THE
SURFACE, BUT THE SYSTEM WILL BE BACK OVER LAND BEFORE IT CAN
COMPLETELY REORGANIZE. THUS, NO ADDITIONAL INTENSIFICATION IS
EXPECTED, THOUGH THE SYSTEM WILL MAKE LANDFALL AS A MINIMAL
TYPHOON-STRENGTH SYSTEM. ONCE ASHORE, TY 05W WILL RAPIDLY WEAKEN
AND FULLY DISSIPATE BY TAU 48. 

MODEL DISCUSSION: TRACK GUIDANCE IS IN VERY GOOD AGREEMENT THAT THE
SYSTEM WILL TRACK WEST-NORTHWESTWARD THEN NORTHWESTWARD FOR THE
DURATION OF THE FORECAST PERIOD. THE JTWC FORECAST DEVIATES SOUTH
OF THE GUIDANCE ENVELOPE FOR THE FIRST 12 HOURS IN LIGHT OF THE
RECENTLY OBSERVED TRACK MOTION, BUT THEN REJOINS THE GUIDANCE
PACKAGE FOR THE REMAINDER OF THE FORECAST, WITH HIGH CONFIDENCE.
INTENSITY GUIDANCE IS ALSO IN VERY GOOD AGREEMENT, WITH ALL
AVAILABLE MODELS INDICATING RAPID DECAY, WEAKENING AND DISSIPATION
BY TAU 48, LENDING HIGH CONFIDENCE TO THE JTWC FORECAST. 

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