WDPN32 PGTW 102100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 16W (PODUL) WARNING NR 
016//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 21.3N 134.7E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 420 NM WEST-SOUTHWEST OF IWO TO
   MOVEMENT PAST 6 HOURS: WESTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
STORM (TS) 16W (PODUL) WITH AN INCREASINGLY OBSCURED LOW-LEVEL
CIRCULATION CENTER. CONVECTION HAS CONTINUED TO SLOWLY BUILD IN
CLOSE PROXIMITY TO THE LLCC, HOWEVER, THE NORTHERN SEMICIRCLE HAS
REMAINED VOID OF ANY SUBSTANTIAL CONVECTION WHILE DRY AIR HAS
REMAINED EVIDENT, REVEALING FRAGMENTED LOW-LEVEL CLOUD LINES
WRAPPING INTO AN ASYMMETRIC CENTER. ALOFT, MODERATE EQUATORWARD 
OUTFLOW HAS BEEN OBSERVED ON ANIMATED WATER VAPOR IMAGERY, WHILE DRY 
AIR CONTINUES TO WRAP AROUND THE NORTHERN PERIPHERY OF TS 16W AND 
INTO THE SOUTHERN QUADRANT. THE CURRENT ENVIRONMENT IS ASSESSED AS
MARGINALLY FAVORABLE, WITH WARM SEA SURFACE TEMPERATURES (29-30 C),
UNFAVORABLE VERTICAL WIND SHEAR (VWS) OF 25-30 KTS, AND PRESENT DRY
AIR. THE INITIAL POSITION IS ASSESSED WITH MEDIUM CONFIDENCE BASED
ON ANIMATED EIR SATELLITE IMAGERY AND EXTRAPOLATION FROM AN EARLIER
10144853Z OCEANSAT-3 IMAGE. THE INITIAL INTENSITY IS ASSESSED WITH
MEDIUM CONFIDENCE BASED ON PERSISTENCE AND A COMBINATION OF
OBJECTIVE CIMSS ESTIMATES AND SUBJECTIVE AGENCY ESTIMATES LISTED
BELOW.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE TO THE
NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T3.5 - 55 KTS
   KNES: T3.0 - 45 KTS
   CIMSS ADT: 35 KTS AT 101900Z
   CIMSS AIDT: 35 KTS AT 101900Z
   CIMSS D-PRINT: 35 KTS AT 101900Z

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

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TS 16W IS FORECASTED TO TRACK WESTWARD
THROUGHOUT THE NEXT 24 HOURS AND BEGIN A GENERALLY NORTHWESTWARD
TRACK INTO TAU 96 AROUND THE SOUTHERN AND SOUTHWESTERN PERIPHERY OF
THE SUBTROPICAL STEERING RIDGE LOCATED DIRECTLY TO THE NORTH AND
NORTH-NORTHEAST. DURING THE SYSTEMS TRACK NORTHWESTWARD, THE TS 16W
IS EXPECTED TO MAKE AN INITIAL LANDFALL NEAR TAU 60 OVER TAIWAN,
REEMERGE OVER WATER AT TAU 66, AND MAKE ITS FINAL LANDFALL NEAR TAU
72 IN SOUTHEASTERN FUJIAN PROVINCE, CHINA. WITH REGARD TO
INTENSITY, TS PODUL IS FORECASTED TO INTENSIFY OVER THE NEXT 48
HOURS AS THE CENTRAL CORE OF THE SYSTEM MOISTENS WHILE DRY AIR
REMAINS ON THE PERIPHERY OF THE RELATIVELY SMALL CIRCULATION.
ADDITIONALLY, SEA SURFACE TEMPERATURES ARE EXPECTED TO REMAIN VERY
WARM, BETWEEN 29-31 C, AND AN ADDITIONAL EQUATORWARD OUTFLOW
CHANNEL IS EXPECTED TO DEVELOP DURING THE APPROACH TO TAIWAN. AFTER
LANDFALL OVER TAIWAN, INTENSITIES WILL DECREASE THROUGH INTERACTION
WITH THE TERRAIN. AS THE SYSTEM TRACKS INTO THE TAIWAN STRAIT
WITHIN COOLER WATERS OF LESS THAN 26 C AND APPROACHES ITS SECOND
LANDFALL, INTENSITIES OF 40 KTS ARE EXPECTED NEAR LANDFALL AT TAU
72. AFTER LANDFALL, INTENSITIES WILL WEAKEN FURTHER TOWARD COMPLETE
DISSIPATION OF 20 KTS NEAR TAU 96.

MODEL DISCUSSION: NUMERICAL WEATHER PREDICTION (NWP) TRACK
SOLUTIONS ARE IN FAIR AGREEMENT THROUGH THE INITIAL 72 HOURS OF THE
FORECAST PERIOD, WITH A CROSS-TRACK OF 190 NM AT THE SYSTEMS
INITIAL LANDFALL OVER TAIWAN NEAR TAU 60, AND A CROSS-TRACK SPREAD
OF 288 NM AT TS PODULS SECOND LANDFALL NEAR TAU 72 IN FUJIAN
PROVINCE, CHINA. AFTER TAU 72, TRACK SOLUTIONS DIVERGE
SIGNIFICANTLY, INCREASING THE CROSS-TRACK TO 917 NM DUE TO
INTERACTION WITH SOUTHEAST CHINAS TERRAIN. DUE TO THIS, THE JTWC
TRACK FORECAST IS ALIGNED CLOSELY TO THE MULTI-MODEL TRACK
CONSENSUS WITH MEDIUM CONFIDENCE THROUGH TAU 72, AND LOW CONFIDENCE
BETWEEN TAU 72 AND TAU 96. WITH REGARD TO THE INTENSITY FORECAST,
CONFIDENCE IS LOW THROUGHOUT THE 96 HOUR FORECAST PERIOD. ALTHOUGH
THE ENVIRONMENT IS EXPECTED TO REMAIN JUST MARGINALLY FAVORABLE DUE
TO UNFAVORABLE VWS ABOVE 25 KTS AND PRESENT DRY AIR, A FEW
INTENSITY SOLUTIONS ILLUSTRATE MAXIMUM INTENSITIES BETWEEN 105-115
KTS, PRIMARILY THE GFS DETERMINISTIC SOLUTION AND COAMPS-TC. WITH
THE EXCEPTION OF THOSE TWO INTENSITY MODELS, THE REMAINDER OF THE
JTWC INTENSITY CONSENSUS SOLUTIONS CHARACTERIZE STEADY
INTENSIFICATION RATES TO 70 KTS, WITH A WEAKENING STAGE THEREAFTER
FROM THE INITIAL LANDFALL OVER TAIWAN. DUE TO THE AFOREMENTIONED
ENVIRONMENTAL CONCERNS, THE JTWC INTENSITY FORECAST IS ALIGNED
CLOSELY TO THE MULTI-MODEL CONSENSUS THROUGHOUT THE FORECAST
PERIOD.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   TRACK 72-120 HR: LOW
   INTENSITY 00-72 HR: LOW
   INTENSITY 72-120 HR: LOW//
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