WDPN32 PGTW 130300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 16W (PODUL) WARNING NR 025//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 22.1N 122.0E
   INITIAL INTENSITY: 90 KTS
   GEOGRAPHIC REFERENCE: 182 NM SOUTH OF TAIPEI, TAIWAN
   MOVEMENT PAST 6 HOURS: WESTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 36 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TYPHOON 16W
(PODUL) WITH A MOSTLY-FILLED EYE AND A PROMINENT BAND OF DEEP
CONVECTION TIGHTLY WRAPPING AROUND THE SOUTHERN AND EASTERN SECTORS
OF THE SYSTEM. THE WARM EYE THAT WAS PREVIOUSLY APPARENT IN ANIMATED 
EIR IMAGERY HAS SINCE CLOSED, BUT CLOUD TOPS JUST EAST OF THE CENTER
ARE EXTREMELY COLD (-86 C). THE STRUCTURE OF THE CORE OF THE VORTEX
HAS STEADILY IMPROVED IN ANIMATED RADAR IMAGERY OVER THE PAST 6
HOURS AS IT APPROACHES THE COAST, HINTING AT A CONTINUED
INTENSIFICATION TREND. A 122205Z WSFM 37 GHZ MICROWAVE IMAGE
REVEALED A WELL-DEFINED MICROWAVE EYE FEATURE WITH A SLIGHT
WEAKNESS IN THE NORTHERN PORTION, LIKELY DUE TO THE PERSISTENT
NORTHEASTERLY SHEAR ACTING ON THE SYSTEM. ENVIRONMENTAL ANALYSIS
INDICATES THAT 16W IS IN A FAVORABLE ENVIRONMENT CHARACTERIZED BY
STRONG WESTWARD AND EQUATORWARD OUTFLOW ALOFT, LOW TO MODERATE
(15-20 KTS) NORTHEASTERLY VERTICAL WIND SHEAR, AND VERY WARM (30-31
C) SEA SURFACE TEMPERATURES. THE INITIAL POSITION IS PLACED WITH
HIGH CONFIDENCE BASED ON ANIMATED RADAR IMAGERY FROM TAIWAN AND
EXTRAPOLATION FROM THE MICROWAVE EYE IN THE MENTIONED WSFM IMAGE.
THE INITIAL INTENSITY OF 90 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON THE LISTED AGENCY DVORAK FIXES AND A 130000Z CIMSS DPRINT
ESTIMATE OF 91 KTS.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A SUBTROPICAL
RIDGE CENTERED OVER SOUTHERN HONSHU

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   RJTD: T4.5 - 77 KTS
   RCTP: T5.5 - 102 KTS
   KNES: T4.5 - 77 KTS
   CIMSS D-PRINT: 91 KTS AT 130000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG WESTWARD AND 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: 16W IS FORECAST TO CONTINUE TRACKING
WEST-NORTHWESTWARD, ALONG THE SOUTHWESTERN PERIPHERY OF THE
SUBTROPICAL RIDGE THROUGHOUT THE ENTIRE FORECAST PERIOD. AN INITIAL
LANDFALL ALONG THE SOUTHEASTERN COAST OF TAIWAN IS EXPECTED TO
OCCUR WITHIN THE NEXT COUPLE HOURS, JUST SOUTH OF TAITUNG. A SECOND
LANDFALL IS FORECAST TO OCCUR NEAR TAU 18, ALONG THE SOUTHEASTERN
COAST OF CHINA. ERRATIC TRACK MOTIONS ARE POSSIBLE AS THE VORTEX
INTERACTS WITH THE SOUTHERN EXTENT OF THE CENTRAL MOUNTAIN RANGE.
REGARDING INTENSITY, 16W IS EXPECTED TO REACH ITS PEAK INTENSITY AS
IT MAKES LANDFALL, CURRENTLY ESTIMATED TO BE NEAR 90 KTS NEAR THE
CORE OF THE CIRCULATION. AFTER 16W MAKES LANDFALL IN TAIWAN, THE
MOUNTAINOUS TERRAIN WILL CAUSE THE SYSTEM TO WEAKEN. THE FORECAST
TRACK HAS SLOWLY BEEN SHIFTING SOUTHWARD, AND THEREFORE CAUSING
LESS INTERACTION WITH THE CENTRAL MOUNTAIN RANGE. A BORDERLINE
TYPHOON STRENGTH SYSTEM IS NOW CURRENTLY FORECAST TO EMERGE WITHIN
THE TAIWAN STRAIT. NEVERTHELESS, 16W WILL CERTAINLY WEAKEN AS IT
APPROACHES THE COAST OF CHINA. AFTER THE SECOND LANDFALL, 16W WILL
QUICKLY ERODE WITH DISSIPATION FORECAST TO OCCUR AROUND TAU 36 AS
THE REMNANT VORTEX TRACK FURTHER INLAND.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN VERY CLOSE
AGREEMENT WITH A 72 NM CROSS-TRACK SPREAD AT TAU 24 AND MINIMAL
ALONG-TRACK SPREAD. THE JTWC TRACK FORECAST IS PLACED CLOSE TO THE
MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE. OVERALL, INTENSITY
GUIDANCE AGREES ON A WEAKENING TREND FROM TAU 0 ONWARD. THERE IS
SOME INCREASED UNCERTAINTY REGARDING THE AMOUNT OF WEAKENING 16W
WILL HAVE AFTER THE INITIAL LANDFALL OVER SOUTHERN TAIWAN, LENDING
MEDIUM CONFIDENCE THE JTWC INTENSITY FORECAST.

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