WDPN32 PGTW 120300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 16W (PODUL) WARNING NR 021//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.9N 128.1E
   INITIAL INTENSITY: 65 KTS
   GEOGRAPHIC REFERENCE: 336 NM SOUTH OF KADENA AB
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 29 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TYPHOON 16W
(PODUL) WITH DEEP CONVECTION BUILDING OVER THE CENTER AND
ASSOCIATED CLOUD TOPS MEASURING AS COLD AS -78 C. THE TRACK MOTION
OF 16W HAS ALSO SHIFTED TO AN ANTICIPATED WEST-NORTHWESTWARD
DIRECTION. AN 112313Z GMI 37 GHZ MICROWAVE IMAGE REVEALED AN
ELONGATED, BUT DEFINED MICROWAVE EYE FEATURE AT THE LOW-LEVELS. THE
PREVIOUS RAGGED EYE HAS FALLEN APART OVER THE PAST 6 HOURS, BUT
CENTRAL CONVECTION HAS IMPROVED. THE IMPROVED CENTRAL CONVECTION
SEEMS TO CORRELATE TO A MOISTENED VORTEX CORE. EASTERLY VERTICAL
WIND SHEAR ALSO APPEARS TO HAVE LESSENED AND IS NOW ANALYZED TO BE
AROUND 15-20 KTS. OVERALL, THE ENVIRONMENT IS CHARACTERIZED AS
FAVORABLE DUE TO MODERATE EQUATORWARD OUTFLOW, LOW TO MODERATE
(15-20 KTS) VERTICAL WIND SHEAR, AND WARM (29-30 C) SEA SURFACE
TEMPERATURES. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE
BASED ON A SHORT EXTRAPOLATION FROM THE MENTIONED GMI MICROWAVE
IMAGE. THE INITIAL INTENSITY OF 65 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON THE LISTED AGENCY DVORAK AND OBJECTIVE
INTENSITY ESTIMATES.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF AN ELONGATED
SUBTROPICAL RIDGE POSITIONED TO THE NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T4.0 - 65 KTS
   RCTP: T4.5 - 77 KTS
   KNES: T4.0 - 65 KTS
   CIMSS ADT: 53 KTS AT 120000Z
   CIMSS D-MINT: 53 KTS AT 112313Z
   CIMSS D-PRINT: 56 KTS AT 120000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 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: 16W IS FORECAST TO CONTINUE TRACKING
WEST-NORTHWESTWARD, ALONG THE SOUTHWESTERN PERIPHERY OF THE
ELONGATED SUBTROPICAL RIDGE TO THE NORTHEAST THROUGHOUT THE ENTIRE
FORECAST PERIOD. AN INITIAL LANDFALL IS FORECAST TO OCCUR JUST
AFTER TAU 24, ALONG THE SOUTHEASTERN COAST OF TAIWAN, NEAR TAITUNG.
AFTERWARD, A SECOND AND FINAL LANDFALL IS EXPECTED NEAR TAU 42,
ALONG THE EASTERN COAST OF CHINA. THERE IS POTENTIAL FOR ERRATIC
STORM MOTION AS 16W APPROACHES TAIWAN DUE TO AN INDUCED VORTICITY
PHENOMENON CAUSED BY INTERACTION WITH THE CENTRAL MOUNTAIN RANGE
(CMR). REGARDING INTENSITY, 16W IS FORECAST TO FURTHER INTENSIFY
THROUGH TAU 24 TO A PEAK OF AROUND 80-85 KTS DUE TO WARM SEA
SURFACE TEMPERATURES AND MODERATE EQUATORWARD OUTFLOW. ADDITIONALLY, 
MODEL FIELDS DEPICT THE CORE OF THE VORTEX MOISTENING, WHICH WILL 
FURTHER AID IN THE INTENSIFICATION OF THE SYSTEM. LAND INTERACTION 
WITH THE MOUNTAINS OF TAIWAN WILL CAUSE A WEAKENING TREND TO ENSUE, 
WHICH PERSISTS THROUGH THE REMAINDER OF THE FORECAST PERIOD. AFTER 
THE SECOND LANDFALL EVENT, 16W WILL RAPIDLY DETERIORATE OVER LAND 
WITH DISSIPATION EXPECTED NEAR TAU 72.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN VERY CLOSE
AGREEMENT WITH A 60 NM CROSS-TRACK SPREAD AT TAU 36, AND A 140 NM
CROSS-TRACK SPREAD AT TAU 72. THE JTWC TRACK FORECAST IS PLACED
WITH HIGH CONFIDENCE, CLOSE TO THE MULTI-MODEL CONSENSUS. INTENSITY
GUIDANCE IS IN MODERATE AGREEMENT WITH A COUPLE RAPID INTENSIFICATION 
AIDS CONTINUING TO TRIGGER THIS CYCLE. THERE IS A 35 KNOT SPREAD AT 
TAU 24 WITH PEAK INTENSITIES RANGING FROM 65-100 KTS. GFS IS THE 
WEAKEST MODEL WHILE CTR1 (COAMPS-TC ENSEMBLE RI AID) IS THE 
STRONGEST. THE JTWC INTENSITY FORECAST IS PLACED ABOUT 5 KTS HIGHER 
THAN CONSENSUS THROUGH TAU 24 AND THEN CLOSELY FOLLOWS CONSENSUS 
THEREAFTER WITH MEDIUM CONFIDENCE. 

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