WDPN32 PGTW 101500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 16W (PODUL) WARNING NR 
015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 21.6N 136.0E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 537 NM EAST-SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: WESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 23 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS FLARING
DEEP CONVECTION TILTED SOUTH OF A LOW-LEVEL CIRCULATION CENTER
(LLCC). LOW-LEVEL CLOUD BANDS ARE EXPOSED ALONG THE NORTHERN
PERIPHERY OF TROPICAL STORM (TS) 16W DUE TO STRONG UPPER-LEVEL FLOW
TO THE NORTH TILTING THE VERTICAL STRUCTURE AND INJECTING DRY AIR
INTO THE CORE OF THE SYSTEM. THE INITIAL POSITION IS PLACED WITH
HIGH CONFIDENCE BASED ON 101228Z GPM GMI 37GHZ MICROWAVE IMAGE
DEPICTING WEAK LOW-LEVEL BANDING ALONG THE NORTHERN PERIPHERY AND
STRONG CURVED CLOUD BANDS TO THE SOUTH. ANALYSIS OF THE 89GHZ IMAGE
FROM THE SAME SATELLITE PASS HIGHLIGHTS THE DRY INTRUSION IN THE
NORTHERN SEMICIRCLE AND SOUTHWARD TILT WITH HEIGHT. THE INITIAL
INTENSITY OF 50 KTS IS ASSESSED WITH MEDIUM CONFIDENCE DUE TO MIXED
GUIDANCE. A 101230Z METOP-C ASCAT PARTIAL SCATTEROMETRY IMAGE
REVEALS 35-40KTS IN THE EASTERN SIDE OF THE CIRCULATION, BUT AN
EARLIER 100849Z RCM-3 SYNTHETIC APERTURE RADAR (SAR) WIND SPEED
IMAGE REVEALS PEAKS UP TO 59KTS. TAKING INTO CONSIDERATION THE LOW
BIAS IN METOP-C ASCAT AND HIGH BIAS IN SAR, THE INTENSITY IS
ANALYZED WITH MEDIUM CONFIDENCE AT 50KTS.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: AN ELONGATED SUBTROPICAL RIDGE TO THE
NORTH 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T4.5 - 77 KTS
   RCTP: T3.5 - 55 KTS
   KNES: T4.0 - 65 KTS
   CIMSS ADT: 45 KTS AT 101130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 25-30 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: TS 16W WILL TRACK WESTWARD FOR THE NEXT 24
HOURS. AFTER TAU 24, THE SYSTEM WILL GRADUALLY CURVE NORTHWESTWARD
THROUGH THE END OF THE FORECAST PERIOD. TS 16W WILL MAKE LANDFALL
BETWEEN TAU 72-96. MARGINAL CONDITIONS WILL CONTINUE IN THE
EARLY-TERM FORECAST WITH UNFAVORABLE HIGH VERTICAL WIND SHEAR ABOVE
30KTS, MODERATE EASTERLY UPPER-LEVEL DIFFLUENCE, AND WARM SEA
SURFACE TEMPERATURES. OCEAN HEAT CONTENT AND SEA SURFACE
TEMPERATURES ARE VERY HIGH, WHICH WILL CONTRIBUTE TO THE WEAK RATE OF
INTENSIFICATION THAT IS ANTICIPATED DURING THE FIRST 36 HOURS.
AFTER REACHING A PEAK INTENSITY OF 65KTS AT TAU 36, TS 16W WILL BE
INUNDATED BY ENHANCED UPPER-LEVEL NORTHEASTERLY FLOW CAUSING DRY
AIR TO INTRUDE INTO THE CORE OF THE CIRCULATION AND WEAKEN THE 
VERTICAL STRUCTURE. THE RATE OF WEAKENING WILL CONTINUE AS THE SYSTEM 
PASSES INTO SHALLOWER AND COOLER WATER JUST PRIOR TO LANDFALL BETWEEN 
TAU 72-96. TOPOGRAPHIC INTERACTION ON THE MAINLAND OF CHINA WILL 
DISSIPATE THE SYSTEM FULLY BY THE END OF THE FORECAST PERIOD.

MODEL DISCUSSION: JTWC MULTI-MODEL CONSENSUS TRACK SOLUTIONS ARE
SPREAD BETWEEN SOUTHERN TAIWAN AND JUST NORTH OF TAIWAN. THE
VARIATIONS IN SPREAD ARE BASED ON THE CALCULATED STRENGTH AND EXTENT 
OF THE DEEP-LAYER RIDGE TO THE NORTH. THERE IS A SIGNIFICANT
POSSIBILITY THAT TS 16W WILL INTERACT WITH NORTHEASTERN TAIWAN
AROUND TAU 72, RESULTING IN POSSIBLE TRACK DEFLECTION AND IRREGULAR
MOTION DUE TO TERRAIN-INDUCED VORTICITY WITH THE CENTRAL MOUNTAIN
RANGE (CMR). THE TRACK GUIDANCE IS TIED TO THE INTENSITY SOLUTIONS,
AND THE NORTHERLY TRACKS WILL BE STRONGLY INFLUENCED BY VERTICAL
WIND SHEAR AND DRY AIR FROM THE ENHANCED UPPER-LEVEL FLOW. THE
CONSENSUS TRACKS TO THE SOUTH WILL REMAIN IN MORE ADVANTAGEOUS 
CONDITIONS FOR DEVELOPMENT AND INTENSIFICATION WITH LOWER VERTICAL 
WIND SHEAR AND HIGHER MOISTURE. THE JTWC TRACK FORECAST CONFIDENCE IS 
LOW AFTER TAU 72, AND THE INTENSITY FORECAST CONFIDENCE FOLLOWS SUIT.

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