WDPN32 PGTW 100900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 25W (MAN-YI) WARNING NR 
006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.9N 155.3E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 551 NM EAST OF SAIPAN
   MOVEMENT PAST 6 HOURS: WESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
STORM (TS) 25W (MAN-YI) AS A SYSTEM STRUGGLING TO MAINTAIN ITS
VERTICAL STRUCTURE, AS LOW-LEVEL CONVECTIVE CLOUD LINES CAN BE
OBSERVED WRAPPING CYCLONICALLY INTO THE WESTERN PERIPHERY OF THE
LOW-LEVEL CIRCULATION CENTER (LLCC), WHILE THE PRIMARY CONVECTIVE
STRUCTURE HAS BEGUN TILTING TO THE SOUTHWEST. A 100514Z 91 GHZ
SSMIS IMAGE HAS ALSO CONFIRMED MAN-YI AS BEING TILTED, WITH EVIDENT
CURVED CLOUD LINES INTO AN OBSCURED LLC AND CONTINUED CONVECTION
DISLOCATED FROM THE CENTER TO THE SOUTHEAST WITH AN ADDITIONAL
EQUATORWARD EXTENDING CONVECTIVE LINE IN THE SOUTHEAST QUADRANT.
WITH REGARD TO UPPER-LEVEL OUTFLOW, THE ANIMATED WATER VAPOR LOOP
CONTINUES TO SHOW MODERATE POLEWARD OUTFLOW INTO THE NORTHEASTERN
SECTOR. THE INITIAL POSITION IS PLACED WITH LOW CONFIDENCE BASED ON
THE AFOREMENTIONED OBSCURED LLCC ON THE ANIMATED EIR LOOP AND THE
PREVIOUSLY MENTIONED 91 GHZ SSMIS IMAGE. THE INITIAL INTENSITY IS
SET AT 45 KTS AND ASSESSED WITH MEDIUM CONFIDENCE BASED ON
OBJECTIVE AND SUBJECTIVE AGENCY ESTIMATES LISTED BELOW. THE
ENVIRONMENT IS ASSESSED AS MARGINAL DUE TO PERSISTENT LOW TO
MODERATE VERTICAL WIND SHEAR (VWS) OF 15 TO 20 KTS
ADDING PRESSURE TO THE NORTHWESTERN QUADRANT OF TS 25W AND SWATHS
OF DRY WRAPPING INTO THE CENTER STRUCTURE FROM THE WEST.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF THE SUBTROPICAL
RIDGE (STR)

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T2.5 - 35 KTS
   CIMSS SATCON: 52 KTS AT 0130Z
   CIMSS ADT: 51 KTS AT 100700Z
   CIMSS AIDT: 41 KTS AT 100800Z
   CIMSS DPRINT: 41 KTS AT 100800Z
   CIMSS DMINT: 40 KTS AT 100800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   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: TS 25W IS FORECASTED TO CONTINUE TO TRACK
GENERALLY WESTWARD UNDER THE INFLUENCE OF THE SUBTROPICAL RIDGE
(STR) LOCATED DIRECTLY TO THE NORTH. THE SYSTEM IS EXPECTED TO
REACH MAXIMUM INTENSITY AND INTENSIFY OVER THE NEXT 6 TO 12 HOURS
TO 50 KTS BY TAU 12. FOLLOWING TAU 12, TS MAN-YI IS EXPECTED TO
BEGIN WEAKENING THROUGH THE 96 HOUR FORECAST PERIOD AS CONTINUED
MID-LEVEL DRY AIR WRAPS INTO VERTICAL STRUCTURE AND VWS INCREASES
AND MAINTAINS A 20 TO 30 KT MAGNITUDE THROUGH TAU 92. BY TAU 96, TS
25W IS FORECASTED TO DISSIPATE OVER WATER AS THE ENVIRONMENT
BECOMES INCREASINGLY NON-CONDUCIVE FOR FURTHER DEVELOPMENT. WITH 
REGARD TO FORECAST TRACK, 25W WILL CONTINUE TO TRACK WESTWARD INTO 
TAU 96 ALONG THE SOUTHERN PERIPHERY OF THE SUBTROPICAL RIDGE UNTIL
COMPLETE DISSIPATION AS ADVERSE ENVIRONMENTAL PARAMETERS BEGIN TO
ERODE MAN-YI AFTER TAU 12.    

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT,
WITH A CROSS-TRACK SPREAD OF 83 NM BY TAU 36 AND 160 NM BY TAU 96,
WITH ALL OF THE CONSENSUS MEMBERS FORECASTING A WESTWARD TRACK
UNTIL THE END OF THE FORECAST PERIOD, LENDING HIGH CONFIDENCE OVER
THE NEXT 72 HOURS. THE JTWC TRACK FORECAST IS LAID IN VERY CLOSE
PROXIMITY TO THE MULTI-MODEL CONSENSUS. THE INTENSITY MODEL
GUIDANCE IS ALSO IN GOOD AGREEMENT WITH ALL NUMERICAL MODEL
PREDICTIONS EXPECTING A SHORT INTENSIFICATION PHASE OVER THE NEXT
12 HOURS, AND STEADILY WEAKENING TS 25W THEREAFTER INTO TAU 96. THE
COAMPS-TC ENSEMBLE INTENSITY PROBABILITY PRODUCT INDICATES A STEADY
INTENSITY OVER THE NEXT 6 TO 30 HOURS, FOLLOWED BY MODERATE
WEAKENING BY TAU 96.

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