WDPN32 PGTW 100900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 03W (MEGI) WARNING NR 
006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 10.7N 125.4E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 348 NM SOUTHEAST OF MANILA, PHILIPPINES
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A RAGGED
SYSTEM WITH FRAGMENTED RAIN BANDS AND CENTRAL CONVECTION THAT HAVE
NOW TRACKED ONTO THE CENTRAL ISLANDS OF THE PHILIPPINES. THE
INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON LOW
CLOUD TRACING IN THE MSI LOOP AND TRIANGULATION FROM NUMEROUS
ISLAND WIND OBSERVATIONS. THE INITIAL INTENSITY OF 35KTS IS BASED
ON THE HIGH END OF AGENCY AND AUTOMATED DVORAK ESTIMATES AND IS
SUPPORTED BY THE SURFACE OBSERVATIONS INCLUDING WIND AND MSLP REPORTS
FROM GUIUAN ISLAND 100NM TO THE ENE. ANALYSIS INDICATES AN 
UNFAVORABLE ENVIRONMENT WITH MODERATE VWS, MODERATE POLEWARD 
OUTFLOW, AND WARM SST OFFSET BY FRICTIONAL EFFECTS FROM THE RUGGED 
ISLAND TERRAIN. THE CYCLONE IS QUASI-STATIONARY (QS) AS IT IS 
EMBEDDED IN A SHALLOW TROUGH WITH EASTERLY TRADEWINDS TO THE NORTH 
AND A BELT OF WESTERLIES TO THE SOUTH.

INITIAL WIND RADII BASIS: SURFACE OBSERVATIONS.

CURRENT STEERING MECHANISM: QUASI-STATIONARY IN A SHALLOW TROUGH
WITH EASTERLY TRADEWINDS TO THE NORTH AND A BELT OF WESTERLIES TO
THE SOUTH.   

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T2.0 - 30 KTS
   CIMSS ADT: 41 KTS AT 100230Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 15-20 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: MEDIUM

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE FORECAST TRACK HAS BEEN REDUCED
TO 48HRS, OTHERWISE NO SIGNIFICANT CHANGE TO THE FORECAST
PHILOSOPHY.

FORECAST DISCUSSION: TS MEGI WILL SLOWLY TRACK AND LOOP
CLOCKWISE OVER THE ISLANDS OF LEYTE AND SAMAR AND BY TAU 48, WILL
EXIT BACK INTO THE PHILIPPINE SEA AS IT GETS PULLED INTO AN
APPROACHING CYCLONE THAT IS BIGGER AND STRONGER (TS 02W). THIS
BINARY INTERACTION WILL SUPPRESS ANY SIGNIFICANT DEVELOPMENT OF TD
03W. THIS, IN ADDITION TO THE FRICTIONAL EFFECTS OF THE RUGGED
ISLAND TERRAIN WILL ERODE THE SYSTEM TO DISSIPATION BY TAU 36,
POSSIBLY SOONER. THE REMNANT WILL ACCELERATE EAST-NORTHEASTWARD
TOWARD TS 02W DUE TO THE BINARY INTERACTION.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN OVERALL AGREEMENT WITH
MAINTAINING THE VORTEX OVER THE PHILIPPINE ISLANDS FOR THE NEXT
36-48HR BEFORE EJECTING IT EAST-NORTHEASTWARD TOWARD TS 02W.
HOWEVER, THERE IS A WIDE SPREAD IN THE INITIAL 36-48HR
TRAJECTORIES. IN VIEW OF THIS, THERE IS LOW CONFIDENCE IN THE JTWC
TRACK FORECAST. 

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