WDPN32 PGTW 101500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 25W (MAN-YI) WARNING NR 
007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.8N 154.6E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 510 NM EAST OF SAIPAN
   MOVEMENT PAST 6 HOURS: WESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 19 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
STORM (TS) 25W (MAN-YI) WITH AN INCREASINGLY PARTIALLY EXPOSED
LOW-LEVEL CIRCULATION (LLC) AS THE PRIMARY CONVECTIVE STRUCTURE
REMAINS SLIGHTLY OFFSET TO THE SOUTHEAST. THE WESTERN SEMICIRCLE
REMAINS CLEAR OF ANY CONVECTION WITH EVIDENT DRY AIR WRAPPING INTO
THE SOUTHERN QUADRANT OF THE SYSTEMS CIRCULATION. WEAK UPPER-LEVEL
POLEWARD OUTFLOW HAS BEEN OBSERVED ON ANIMATED WATER VAPOR IMAGERY
OVER THE LAST FEW HOURS INTO A FINGER OF THE MID-LATITUDE WESTERLIES 
WHILE THE SYSTEM HAS STRUGGLED TO INTENSIFY PAST 45 KTS. A PARTIAL 
101135Z ASCAT-C IMAGE HAS ONLY CONFIRMED THE ASSESSMENT OF A MODERATE 
TROPICAL STORM, WITH A SWATH OF 25 KTS IN THE NORTHWESTERN QUADRANT 
AND 30 KTS IN THE SOUTHERN QUADRANT. THE INITIAL POSITION IS PLACED 
WITH MEDIUM CONFIDENCE BASED ON EXTRAPOLATION FROM A 100742Z 91 GHZ 
SSMIS MICROWAVE IMAGE REVEALING SHALLOW LOW-LEVEL CONVECTIVE LINES 
PARTIALLY OBSCURED BY THE AFOREMENTIONED CONVECTIVE FEATURE SLIGHTLY 
OFFSET INTO THE SOUTHEASTERN QUADRANT FROM THE LOW-LEVEL CIRCULATION 
CENTER (LLCC). THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM 
CONFIDENCE BASED ON OBJECTIVE AND SUBJECTIVE AGENCY ESTIMATES LISTED 
BELOW, RANGING FROM 42 KTS TO 50 KTS. THE ENVIRONMENT HAS BEEN 
ASSESSED AS MARGINAL DUE TO INCREASED VERTICAL WIND SHEAR TO 20-25 
KTS, CONTINUING TO ADD PRESSURE ALONG THE WESTERN PERIPHERY OF THE
SYSTEM, WHILE DRY AIR PERSISTS TO ENCROACH INTO THE CORE.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE NORTHWEST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T3.0 - 45 KTS
   KNES: T3.0 - 45 KTS
   CIMSS SATCON: 50 KTS AT 101200Z
   CIMSS ADT: 47 KTS AT 101230Z
   CIMSS AIDT: 42 KTS AT 101230Z
   CIMSS D-MINT: 50 KTS AT 100744Z
   CIMSS D-PRINT: 49 KTS AT 101230Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 20-25 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: WEAK POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: TS 25W IS FORECASTED TO CONTINUE TO TRACK
GENERALLY WESTWARD OVER THE NEXT 48 HOURS AND THEN BEGIN A SLIGHT
TRACK TO THE WEST-SOUTHWEST INTO DISSIPATION AT TAU 72 UNDER THE
INFLUENCE OF THE SUBTROPICAL RIDGE (STR) LOCATED DIRECTLY TO THE
NORTH. THE SYSTEM IS EXPECTED TO MAINTAIN ITS MAXIMUM INTENSITY OF
45 KTS OVER THE NEXT 12 HOURS THEN BEGIN ITS INITIAL WEAKENING
PHASE INTO TAU 72. FOLLOWING TAU 12, SUSTAINED MODERATE TO STRONG
VERTICAL WIND SHEAR OF 20 KTS TO 25 KTS AND INCREASING NEGATIVE
INFLUENCES FROM DRY-AIR ENTRAINMENT WILL ERODE THE SYSTEMS CORE
STRUCTURE, WEAKENING THE INTENSITY OF MAN-YI TO 20 KTS AND
COMPLETING THE DISSIPATION PHASE BY TAU 72. WITH REGARD TO THE
FORECAST TRACK, TS 25W WILL CONTINUE TO TRACK WESTWARD INTO TAU 48
ALONG THE SOUTHERN PERIPHERY OF THE STR TO THE NORTH. AFTER TAU 48,
EQUATORWARD EXTENDING RIDGING FROM THE STR WILL BEGIN TO FORCE A
WEST-SOUTHWEST TRACK TO 25W UNTIL DISSIPATION AT TAU 72.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE CONTINUES TO REMAIN IN
GOOD AGREEMENT, WITH A CROSS-TRACK SPREAD OF 64 NM BY TAU 24 AND
134 NM BY TAU 72. THE MAJORITY OF THE JTWC TRACK CONSENSUS MEMBERS
SHOW A WESTWARD TRACK INTO TAU 48 AND TURNING SLIGHTLY TO THE
WEST-SOUTHWEST BY THE END OF THE FORECAST PERIOD AT TAU 72, LENDING
HIGH CONFIDENCE IN THE JTWC FORECAST. THE JTWC FORECAST TRACK IS
PLACED WITH HIGH CONFIDENCE AND REMAINS ALIGNED AND IN CLOSE
PROXIMITY TO THE MULTI-MODEL JTWC CONSENSUS. NAVGEM REMAINS AS THE
ONLY OUTLIER, ILLUSTRATING A NORTHWEST TRACK BETWEEN TAU 0 AND TAU
72. THE INTENSITY MODEL GUIDANCE CONTINUES TO BE IN FAIR AGREEMENT
WITH ALL NUMERICAL MODEL INTENSITY PREDICTIONS, INDICATING
CONTINUED 45 KTS INTENSITIES OVER THE NEXT 12 HOURS, THEN STEADILY
WEAKENING TS 25W BY TAU 96. THE COAMPS-TC ENSEMBLE INTENSITY
PROBABILITY PRODUCT INDICATES LESS THAN 50 PERCENT OF A STEADY
INTENSITY OVER THE NEXT 36 HOURS, WHILE MODERATE WEAKENING IS
EXPECTED TO BEGIN AT TAU 18 AND CONTINUE THROUGH DISSIPATION BY TAU
72. 

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