WDPN33 PGTW 101500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 24W (KOMPASU) WARNING 
NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.4N 126.6E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 395 NM NORTHEAST OF MANILA, PHILIPPINES
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 15 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A VERY
LARGE MONSOON DEPRESSION WITH WIDE FORMATIVE RAIN BANDS EXTENDING
ALL THE WAY DOWN TO THE SOUTHERN PHILIPPINES THAT ARE WRAPPING 
TIGHTER
INTO A PARTIALLY EXPOSED LLC. THE INITIAL POSITION IS PLACED WITH
MEDIUM CONFIDENCE BASED ON THE PARTLY EXPOSED LLC FEATURE IN THE EIR 
LOOP. THE INITIAL INTENSITY OF 45KTS IS BASED WITH MEDIUM CONFIDENCE 
ON THE PGTW AND KNES DVORAK ESTIMATES AND REFLECTS THE IMPROVED 
CONVECTIVE STRUCTURE. ENVIRONMENTAL ANALYSES INDICATE MARGINALLY 
FAVORABLE CONDITIONS FOR DEVELOPMENT CHARACTERIZED BY WARM SSTS IN 
THE
PHILIPPINE SEA AND STRONG POLEWARD OUTFLOW ALOFT OFFSET BY MODERATE
(15-20KT) VWS. THE CYCLONE IS TRACKING ALONG THE SOUTHWESTERN
PERIPHERY OF THE STR TO THE NORTHEAST.

INITIAL WIND RADII BASIS: PERSISTENCE.

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE
NORTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T2.5 - 35 KTS
   KNES: T3.0 - 45 KTS
   CIMSS ADT: 35 KTS AT 101140Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG POLEWARD

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: THE STR IS EXPECTED TO BUILD AND EXTEND
WESTWARD AND DRIVE THE SYSTEM WEST-NORTHWESTWARD THEN DUE WESTWARD
THROUGH THE LUZON STRAIT, INTO THE SOUTH CHINA SEA (SCS), ACROSS
HAINAN AND THE GULF OF TONKIN BEFORE MAKING LANDFALL IN NORTHERN
VIETNAM AROUND TAU 96. THE MARGINALLY FAVORABLE ENVIRONMENT WILL
FUEL GRADUAL INTENSIFICATION TO A PEAK OF 65KTS IN THE SCS WHERE
THE ENVIRONMENT IS EXPECTED TO BE MORE FAVORABLE. AFTERWARD,
INCREASING VWS WILL SLOWLY WEAKEN THE SYSTEM DOWN TO 50KTS AT TAU
72 AS IT TRACKS OVER HAINAN. AFTER LANDFALL, INTERACTION WITH THE
RUGGED VIETNAMESE TERRAIN WILL RAPIDLY ERODE THE SYSTEM DOWN TO
20KTS AFTER IT CROSSES INTO CAMBODIA.     

MODEL DISCUSSION: NUMERICAL MODELS REMAIN IN TIGHT AGREEMENT.
HOWEVER, GIVEN THE FORMATIVE NATURE OF THE SYSTEM AND ITS LARGE
LLC, THERE IS ONLY MEDIUM CONFIDENCE IN THE JTWC TRACK FORECAST UP
TO TAU 120. CONSEQUENTLY, THERE IS ALSO MEDIUM CONFIDENCE IN THE
INTENSITY FORECAST UP TO TAU 120.

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