WDPN31 PGTW 220300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 25W (TWENTYFIVE) 
WARNING NR 010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.9N 119.2E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 315 NM EAST-SOUTHEAST OF HONG KONG
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 10 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A COMPACT
SYSTEM WITH A DEEP, FLARING, CENTRAL CONVECTION OBSCURING A WEAK
AND ILL-DEFINED LOW LEVEL CIRCULATION (LLC). RAIN BANDS ARE
FRAGMENTED AND WRAPPING IN VERY LOOSELY TOWARD THE LLC. LONG
STRATOCUMULUS CLOUD LINES, ASSOCIATED WITH THE NORTHEAST COLD SURGE
IN THE TAIWAN STRAIT AND INTO THE SOUTH CHINA SEA, ARE FEEDING IN
FROM THE NORTH TO NORTHWEST. THE INITIAL POSITION IS PLACED WITH
MEDIUM CONFIDENCE USING LOW CLOUD TRACING INTO THE OBSCURED LLC.
THE INITIAL INTENSITY OF 25KTS IS BASED ON AN OVERALL ASSESSMENT OF
AGENCY AND AUTOMATED DVORAK ESTIMATES AND TRENDS AND EXTRAPOLATED
FORM NEARBY SURFACE OBSERVATIONS.

INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).

CURRENT STEERING MECHANISM: WESTERN EXTENSION OF THE SUBTROPICAL
RIDGE (STR) TO THE NORTH. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   RJTD: T1.0 - 25 KTS
   KNES: T1.5 - 25 KTS
   CIMSS ADT: 32 KTS AT 212040Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 0-5 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TD 24W WILL CONTINUE ON A MORE
WEST-SOUTHWESTWARD TO SOUTHWESTWARD ALONG THE SOUTHEASTERN
PERIPHERY OF THE NOW DOMINANT WESTERN EXTENSION OF THE STR AND
TRACK TOWARD CENTRAL VIETNAM, MAKING LANDFALL JUST AFTER TAU 72
NEAR DANANG. THE MARGINALLY FAVORABLE ENVIRONMENT WILL FUEL A WEAK
INTENSIFICATION TO A PEAK OF 35KTS AT TAUS 24-36. AFTERWARD THE
ENVIRONMENT WILL BECOME UNFAVORABLE MOSTLY DUE TO THE INCREASING
IMPACT OF PERSISTENT COLD DRY AIR ASSOCIATED WITH THE NORTHEASTERLY
SURGE IN THE SOUTH CHINA SEA, LEADING TO A GRADUAL DECAY AND
EVENTUAL DISSIPATION BY TAU 96 AS THE SYSTEM TRACKS, DEEPER INTO
THE RUGGED TERRAIN OF THE INDOCHINA PENINSULA. THERE IS NOW A
DISTINCT POSSIBILITY THAT TD 25W WILL DISSIPATE OVER WATER BEFORE
REACHING VIETNAM.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN TIGHT AGREEMENT WITH A
GRADUAL AND EVEN SPREAD TO 100NM BY TAU 72 THEN MORE PRONOUNCED
SPREAD TO 180NM BY TAU 96. IN VIEW OF THIS, THERE IS HIGH
CONFIDENCE IN THE JTWC TRACK FORECAST UP TO TAU 72 THEN LOW
CONFIDENCE AFTERWARD.


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