WDPN33 PGTW 012100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 10W (HAIKUI) WARNING NR 018//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 21.9N 127.1E
   INITIAL INTENSITY: 80 KTS
   GEOGRAPHIC REFERENCE: 279 NM SOUTH OF KADENA AB
   MOVEMENT PAST 6 HOURS: WESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 32 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
TYPHOON STRENGTH TROPICAL CYCLONE THAT IS BEING CONVECTIVELY
DEFORMED BY BOTH VERTICAL WIND SHEAR AND DRY AIR ENTRAINMENT. A
011713Z SUITE OF AMSR2 MICROWAVE IMAGERY PROVIDED A CORNUCOPIA OF
INFORMATION ABOUT THE INNER STRUCTURE OF 10W. ANALYSIS OF THE 89GHZ
AND 37GHZ MICROWAVE IMAGERY INDICATES THAT 10W STILL POSSESSES AN
EYE FEATURE THROUGHOUT THE VERTICAL COLUMN. THE LOCATION OF THIS
FEATURE HOWEVER, IS OFFSET FROM ONE ANOTHER, INDICATING A TILTING
WITH HEIGHT. THE VAST MAJORITY OF DEEP CONVECTION IS ALSO LIMITED
TO THE SOUTHERN SEMICIRCLE DUE TO THE COOL DRY AIR COMING DOWN FROM
THE NORTH. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE
BASED ON EIR AND AMSR2 IMAGERY. THE INITIAL INTENSITY OF 80 KTS IS
ASSESSED WITH MEDIUM CONFIDENCE BASED ON DVORAK INTENSITY ESTIMATES
INDICATING A RANGE OF 65-90KTS WHILE AUTOMATED INTENSITY ESTIMATES
HOVER JUST BELOW 80KTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE (STR) TO
THE NORTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T4.0 - 65 KTS
   RCTP: T5.0 - 90 KTS
   CIMSS ADT: 77 KTS AT 011420Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 20-25 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

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 10W (HAIKUI) IS FORECAST TO REMAIN ON A
GENERALLY WESTWARD AND EVENTUALLY WEST-NORTHWESTWARD COURSE
THROUGHOUT THE ENTIRE FORECAST PERIOD, DUE TO THE STR TO THE
NORTHEAST. OVER THE NEXT 12 HOURS, AS 10W MOVES WESTWARD AND AWAY
FROM THE STRONG UPPER LEVEL LOW TO THE NORTHEAST, VERTICAL WIND
SHEAR (VWS) VALUES ARE FORECAST TO DROP, ALONG WITH REDUCED DRY AIR
ENTRAINMENT FROM THE NORTH. IF THE SYSTEM CAN CORRECT THE
AFOREMENTIONED TILTING AND RECONSOLIDATE ITS CONVECTION, AS VWS
TEMPORARILY DECREASES, MODERATE OUTFLOW COMBINED WITH WARM SSTS
COULD FUEL THE SYSTEM TO AN ESTIMATED PEAK INTENSITY OF 100KTS BY
TAU 24. JUST AFTER TAU 36, 10W WILL MAKE LANDFALL OVER SOUTHERN
TAIWAN AND BY TAU 48, THE SYSTEM WILL BEGIN A TRANSIT ACROSS THE
TAIWAN STRAIT. BY TAU 96, 10W WILL MAKE ITS SECOND LANDFALL OVER
THE CHINESE EASTERN SEABOARD AND PROCEED INLAND WHERE IT WILL
CONTINUE TO ERODE THROUGH TAU 120.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN FAIR AGREEMENT, WITH MOST
MEMBERS GENERALLY FOLLOWING THE JTWC TRACK FORECAST. AFTER TAU 12,
ALONG TRACK AND CROSS TRACK SPREADING INCREASES, RESULTING IN A
120NM SPREAD IN SOLUTIONS BY THE TIME OF INITIAL LANDFALL OVER
TAIWAN AND 150NM SPREAD BY TAU 120. FOR THESE REASON THE JTWC TRACK
FORECAST IS PLACED WITH OVERALL MEDIUM CONFIDENCE.  RELIABLE MODEL
INTENSITY GUIDANCE IS IN FAIR AGREEMENT AS WELL, WITH ALL MEMBERS
SHOWING SOME DEGREE OF INTENSIFICATION THROUGH TAU 24, AFTER WHICH
A DOWNWARD TREND THROUGH THE REMAINING FORECAST PERIOD. COAMPS-TC
AND HAFS-A BOTH SHOW A MUCH LARGER SPIKE THROUGH TAU 12, EACH
PEAKING NEAR 130KTS. BASED ON THE INITIAL VARIABILITY IN THE MODEL
SOLUTIONS, THE JTWC INTENSITY FORECAST IS PLACED WITH OVERALL
MEDIUM CONFIDENCE.

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