WDPN32 PGTW 132100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 25W (MAN-YI) WARNING NR 
020//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 11.6N 139.5E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 151 NM NORTH-NORTHEAST OF YAP
   MOVEMENT PAST 6 HOURS: WESTWARD AT 17 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THE SYSTEM
CONTINUED TO CONSOLIDATE AS INDICATED BY COOLING CLOUD TOPS IN THE
COLD CENTRAL COVER AND TIGHTENING WRAP OF THE FEEDER BAND INTO AN
OBSCURED LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION
IS PLACED WITH HIGH CONFIDENCE BASED ON A DEFINED MICROWAVE LLCC
FEATURE IN THE 131749Z GPM 37GHZ IMAGE. THE INITIAL INTENSITY IS
ALSO ASSESSED WITH HIGH CONFIDENCE BASED ON OVERALL ASSESSMENT OF
AGENCY AND AUTOMATED DVORAK ESTIMATES AND REFLECTS THE SLIGHT
IMPROVEMENT SEEN IN THE 6-HR EIR LOOP. ANALYSIS INDICATES A
FAVORABLE ENVIRONMENT WITH WARM SST IN THE PHILIPPINE SEA, LOW VWS,
AND WEAK RADIAL OUTFLOW.

INITIAL WIND RADII BASIS: PERSISTENCE.

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO
THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T3.0 - 45 KTS
   RCTP: T2.5 - 35 KTS
   KNES: T2.5 - 35 KTS
   CIMSS ADT: 40 KTS AT 131730Z
   CIMSS DPRNT: 30 KTS AT 131730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 05-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: WEAK RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   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 MAN-YI WILL TRACK WESTWARD THEN
NORTHWESTWARD, MAKING LANDFALL OVER CENTRAL LUZON NEAR BALER AFTER
TAU 72, TRACK ACROSS LUZON THEN EXIT INTO THE SOUTH CHINA SEA (SCS)
NEAR LINGAYEN GULF BEFORE TAU 96. THE ENVIRONMENT WILL BECOME
HIGHLY FAVORABLE AS UPPER LEVEL OUTFLOW IMPROVES LEADING TO RAPID
INTENSIFICATION (RI) TO A PEAK OF 125KTS BY TAU 48. AFTERWARD, LAND
INTERACTION WILL REDUCE THE SYSTEM TO 80KTS AT TAU 96 AFTER IT
EXITS INTO THE SCS. COOLING SSTS IN THE SCS, INCREASING VWS AND A
COLD NORTHEASTERLY SURGE WILL RAPIDLY ERODE THE SYSTEM TO 65KTS BY
TAU 120.   

MODEL DISCUSSION: NUMERICAL MODELS ARE IN FAIR AGREEMENT WITH A
GRADUAL SPREAD TO 233NM BY TAU 72, LENDING MEDIUM CONFIDENCE TO
THIS PORTION OF THE JTWC TRACK AND INTENSITY FORECASTS. AFTERWARD,
LOW CONFIDENCE DUE TO UNCERTAINTIES ASSOCIATED WITH LAND PASSAGE. 

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