WDPN32 PGTW 130900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 16W (PODUL) WARNING NR 026//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 22.9N 120.6E
   INITIAL INTENSITY: 75 KTS
   GEOGRAPHIC REFERENCE: 141 NM SOUTH-SOUTHWEST OF TAIPEI, TAIWAN
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 16 KTS
   SIGNIFICANT WAVE HEIGHT: XX FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI), ANIMATED RADAR DATA
FROM TAIWAN CWB AND SURFACE OBSERVATION DATA INDICATE THAT TYPHOON
(TY) 16W MADE LANDFALL JUST SOUTH OF TAITUNG, TAIWAN AT
APPROXIMATELY 130430Z. SURFACE OBSERVATIONS FROM LAN YU ISLAND IN
THE SOUTHERN EYEWALL INDICATED 111 KNOT SUSTAINED WINDS, WHICH WHEN
REDUCED TO THE SURFACE SUPPORTED AN INCREASE IN THE 0000Z INTENSITY
TO 95 KNOTS. THE LANDFALL INTENSITY IS THUS ESTIMATED TO HAVE BEEN
95-100 KNOTS. THE DEPICTION IN BOTH THE MSI AND RADAR RAPIDLY
DETERIORATED AFTER LANDFALL AS THE SYSTEM WAS TORN ASUNDER BY THE
RUGGED TERRAIN OF THE SOUTHERN PORTION OF THE CENTRAL MOUNTAIN
RANGE. SURFACE OBSERVATIONS HOWEVER, FROM AROUND THE REGION
INCLUDING TAINAN, KAOHSIUNG, AND CHAIYI HAVE PROVIDED SOLID
EVIDENCE THAT THE SYSTEM IS PASSING NORTH OF TAINAN AIRPORT AS OF
THE 0700Z HOUR AND WILL MOVE BACK OVER WATER WITHIN THE NEXT COUPLE
OF HOURS. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE
BASED ON BOTH THE CWB RADAR DATA AND THE SURFACE OBSERVATIONS. THE
INITIAL INTENSITY IS ASSESSED WITH LOW CONFIDENCE DUE TO A LACK OF
OBJECTIVE AND SUBJECTIVE INTENSITY ESTIMATES. ENVIRONMENTAL
CONDITIONS ARE OVERALL MARGINALLY FAVORABLE, WITH MODERATE EASTERLY
SHEAR, WARM SSTS IN THE TAIWAN STRAIT AND DECENT WESTWARD OUTFLOW
ALOFT. HOWEVER, THE VORTEX DISRUPTION CAUSED BY THE TRANSIT OVER
TERRAIN IS A SIGNIFICANT HINDRANCE.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF A SUBTROPICAL
RIDGE (STR) WHICH EXTENDS FROM SOUTH-CENTRAL CHINA TO THE NORTH
PACIFIC. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: NO CURRENT ESTIMATE
   RJTD: T5.0 - 90 KTS
   CIMSS D-PRINT: 86 KTS AT 130600Z

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

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TY 16W WILL MOVE BACK OVER WATER ALONG THE
WEST COAST OF TAIWAN, NORTH OF TAINAN, WITHIN THE NEXT 1-2 HOURS.
THE SYSTEM IS EXPECTED TO PASS SOUTH OF PENGHU AIRPORT, LIKELY
TRACKING BETWEEN QIMEI AND WANG'AN ISLANDS ON ITS WAY ACROSS THE
TAIWAN STRAIT. A SECOND LANDFALL IS EXPECTED ALONG THE CHINESE
COAST SOUTH OF XIAMEN WITHIN THE NEXT 12 HOURS, FOLLOWED BY A
NORTHWESTWARD TRACK FURTHER INTO SOUTHERN CHINA. THE SYSTEM HAS
WEAKENED SIGNIFICANTLY AFTER MAKING LANDFALL, BUT IS LIKELY TO
EMERGE INTO THE TAIWAN STRAIT AS A WEAK TYPHOON. CONDITIONS ARE
MARGINAL IN THE STRAIT AND THE VORTEX THAT EMERGES OFF TAIWAN WILL
BE HIGHLY TILTED AND SHREDDED IN THE LOWER-LEVELS. THUS, THE SYSTEM
IS UNLIKELY TO INTENSIFY AS IT CROSSES THE STRAIT AND IS EXPECTED
TO MAKE LANDFALL IN CHINA AS A MINIMAL TYPHOON. TY 16W WILL RAPIDLY
WEAKEN AND ULTIMATELY DISSIPATE OVER MAINLAND CHINA WITHIN THE NEXT
36 HOURS. 

MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE IS IN TIGHT CROSS-
AND ALONG-TRACK AGREEMENT THROUGH THE FORECAST PERIOD, LENDING HIGH
CONFIDENCE TO THE JTWC FORECAST, WHICH IS PLACED ON THE SOUTHERN
EDGE OF THE GUIDANCE PACKAGE. INTENSITY GUIDANCE IS ALSO IN GOOD
AGREEMENT WITH ALL OF THE MODELS AGREEING ON A STEADY WEAKENING
THROUGH THE FORECAST PERIOD. HOWEVER, THE MESOSCALE MODELS ARE
LIKELY WEAKENING THE SYSTEM TOO QUICKLY, WHILE THE DECAY-SHIPS
PRESENTS A MORE REASONABLE RATE OF WEAKENING. THE JTWC FORECAST IS
PLACED ON TOP OF THE DECAY-SHIPS THROUGH THE BULK OF THE FORECAST
PERIOD, WITH HIGH CONFIDENCE. 

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   INTENSITY 00-72 HR: HIGH//
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