WDPN32 PGTW 111500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 32W (FUNG-WONG) WARNING 
NR 030//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.6N 119.1E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 595 NM SOUTHWEST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
STORM 32W (FUNG-WONG) WITH A CIRCULATION THAT IS NOW NEARLY
COMPLETELY DEVOID OF DEEP CONVECTION. AN 111013Z GMI 37 GHZ
MICROWAVE IMAGE REVEALED THAT THE LOW-LEVEL CIRCULATION CENTER
(LLCC) REMAINS WELL-DEFINED WITH A LARGE MICROWAVE EYE FEATURE
STILL PRESENT. THE INITIAL POSITION IS PLACED WITH MEDIUM
CONFIDENCE BASED ON EXTRAPOLATION FROM THE GMI IMAGE. THE INITIAL
INTENSITY OF 50 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE
AGENCY DVORAK FIXES AND OBJECTIVE INTENSITY ESTIMATES LISTED BELOW.
ADDITIONALLY, SURFACE OBSERVATIONS AT DONGSHA DAO ARE REPORTING 41
KTS OUT OF THE NORTH AT 111200Z. ENVIRONMENTAL ANALYSIS INDICATES
THAT 32W IS IN AN UNFAVORABLE ENVIRONMENT CHARACTERIZED BY STRONG
POLEWARD OUTFLOW AND WARM (27-28 C) SEA SURFACE TEMPERATURES,
GREATLY OFFSET BY HIGH (20-25 KTS) SOUTHEASTERLY VERTICAL WIND
SHEAR AND SIGNIFICANT DRY AIR ENTRAINMENT.

INITIAL WIND RADII BASIS: PERSISTENCE WITH SLIGHT ADJUSTMENTS BASED
ON THE OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP-LAYERED
SUBTROPICAL RIDGE CENTERED TO THE EAST


AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T3.0 - 45 KTS
   RCTP: T3.0 - 45 KTS
   KNES: T3.0 - 45 KTS
   CIMSS ADT: 55 KTS AT 111200Z
   CIMSS AIDT: 52 KTS AT 111200Z
   CIMSS D-MINT: 46 KTS AT 111013Z
   CIMSS D-PRINT: 38 KTS AT 111200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 20-25 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: SIGNIFICANT DRY AIR ENTRAINMENT

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: TS 32W IS FORECAST TO CONTINUE ROUNDING THE
WESTERN EXTENT OF THE SUBTROPICAL RIDGE WITH A GENERALLY
NORTHEASTWARD TRACK THROUGH TAU 48. LANDFALL WITHIN THE SOUTHERN
COAST OF TAIWAN IS EXPECTED TO OCCUR AROUND TAU 18. THE ENVIRONMENT
WILL CONTINUE TO BE UNFAVORABLE, CAUSING 32W TO WEAKEN THROUGH ITS
APPROACH TO TAIWAN. THE SYSTEM WILL THEN SKIRT ACROSS SOUTHERN
TAIWAN AND EMERGE BACK OVER WATER. OF NOTE, THE TRACK FORECAST HAS
SLIGHTLY SHIFTED SOUTHWARD, CAUSING THERE TO BE LESS INTERACTION
WITH THE MOUNTAINS OF TAIWAN. THIS WILL ALLOW THE SYSTEM TO
MAINTAIN TROPICAL STORM STRENGTH WINDS FOR A LONGER PERIOD AFTER
LANDFALL THAN PREVIOUSLY FORECAST. NONETHELESS, THE COMBINATION OF
EFFECTS FROM TERRAIN INTERACTION, INCREASING WESTERLY VERTICAL WIND
SHEAR, AND SIGNIFICANT AMOUNTS OF DRY AIR WILL FURTHER DETERIORATE
THE VORTEX. 32W IS THEN EXPECTED TO QUICKLY BECOME ABSORBED INTO
THE FORMING FRONTAL BOUNDARY NO LATER THAN TAU 72, NEAR OKINAWA.
THE FINAL FORECAST INTENSITY OF 30 KTS IS REFLECTIVE OF THE
BACKGROUND WINDS ASSOCIATED WITH THE FRONTAL BOUNDARY AS THE VORTEX
OF 32W COMPLETELY WASHES OUT.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT
THROUGH TAU 36 WITH A CROSS-TRACK SPREAD OF AROUND 50 NM. AFTER TAU
36, MODELS RAPIDLY BEGIN TO DIVERGE WITH DIFFERING REACTIONS TO THE
INTERACTION WITH THE FRONTAL BOUNDARY. SOME MODELS TURN THE SYSTEM
SHARPLY TOWARD THE SOUTHEAST (GFS AND JGSM) WHILE OTHERS CONTINUE
ON AN EAST-NORTHEASTWARD TRACK (ECMWF AND AI MODELS). THE JTWC
TRACK FORECAST IS PLACED CLOSER TO THE ECMWF AND AI MODELS WITH
MEDIUM CONFIDENCE. INTENSITY GUIDANCE AGREES ON WEAKENING THROUGH
TAU 24, BUT THEN DISAGREES AFTERWARD. SOME MODELS DEPICT CONSISTENT
WEAKENING WHILE OTHERS MAINTAIN AROUND 40-45 KTS THROUGH TAU 48,
LIKELY ACCOUNTING FOR THE BACKGROUND SURGE FLOW. THE JTWC INTENSITY
FORECAST IS PLACED SLIGHTLY BELOW THE CONSENSUS FROM TAU 48 ONWARD
IN AN ATTEMPT TO ACCOUNT FOR THE WINDS PRIMARILY ASSOCIATED WITH
32W. THIS DISAGREEMENT CAUSES THERE TO BE LOW CONFIDENCE IN THE
JTWC INTENSITY FORECAST.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   INTENSITY 00-72 HR: LOW//
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