WDPN32 PGTW 111500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 25W (MAN-YI) WARNING NR 
011//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.0N 152.2E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 444 NM EAST OF NAVSTA GUAM
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 02 KTS
   SIGNIFICANT WAVE HEIGHT: 17 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
STORM (TS) 25W (MAN-YI) WITH SPORADIC AND DISORGANIZED FLARING
CONVECTION WITHIN THE EASTERN SEMICIRCLE, WHILE THE WESTERN SECTOR
REMAINS RELATIVELY CONVECTION FREE AS DRY AIR HAS REMAINED
PREVALENT. ALTHOUGH THE WESTERN QUADRANT HAS REMAINED FREE OF ANY
SUPPORTIVE CONVECTION, WEAK CYCLONIC ROTATION IN THE LOW- TO
MID-LEVELS HAS BEEN OBSERVED OVER THE LAST FEW HOURS WITH WEAKLY
ROTATING CLOUD LINES INTO AN OBSCURED LOW-LEVEL CIRCULATION CENTER
(LLCC). THE ANIMATED WATER VAPOR LOOP ALSO ILLUSTRATES A SLOWLY
CONSOLIDATING SYSTEM WITH WEAK POLEWARD AND EQUATORWARD UPPER-LEVEL
OUTFLOW. FROM SIX HOURS AGO, 25W CONTINUES TO BE NEGATIVELY
INFLUENCED BY DRY AIR WRAPPING INTO THE SOUTHERN QUADRANT FROM THE 
WEST, WHILE NORTH-NORTHWESTERLY SHEAR CONTINUES TO SLOW 
INTENSIFICATION. THE INITIAL POSITION IS PLACED WITH MEDIUM 
CONFIDENCE BASED ON EXTRAPOLATION FROM AN 110725Z 91 GHZ SSMIS IMAGE, 
INDICATING AN ILL-DEFINED LLCC AND LESS CONVECTION THAN A FEW HOURS 
AGO. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE BASED 
ON AN EARLIER 110728Z SMAP WINDSPEED PRODUCT, SHOWING AN ISOLATED 
SWATH OF 40 KNOT INTENSITIES IN THE EASTERN QUADRANT OF TS 25W.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE NORTH,
EXTENDING WESTWARD. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T3.0 - 45 KTS
   CIMSS SATCON: 48 KTS AT 111200Z
   CIMSS ADT: 34 KTS AT 111230Z
   CIMSS AIDT: 34 KTS AT 111230Z
   CIMSS D-MINT: 21 KTS AT 110728Z
   CIMSS D-PRINT: 30 KTS AT 111230Z

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

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
WESTWARD OVER THE NEXT 48 HOURS ALONG THE SOUTHERN PERIPHERY OF THE
SUBTROPICAL RIDGE (STR) LOCATED TO THE NORTH. AFTER TAU 48, MAN-YI
IS EXPECTED TO BEGIN ITS WEST-SOUTHWEST TREK INTO TAU 96. FOLLOWING
TAU 48, TS 25W WILL ALSO BEGIN ITS ANTICYCLONIC TRACK AROUND THE
SOUTHWESTERN PERIPHERY OF THE AFOREMENTIONED STR UNTIL THE END OF
THE FORECAST PERIOD. WITH REGARD TO THE INTENSITY OF THE SYSTEM,
MAN-YI IS FORECASTED TO STEADILY INTENSIFY TO 45 KTS JUST EAST OF
THE MARIANAS ISLANDS AT TAU 36. AS 25W TRACKS IN CLOSE PROXIMITY TO 
GUAM, INTENSITIES ARE EXPECTED TO CONTINUE INCREASING TO 50 KTS INTO 
ITS WEST-SOUTHWEST TRACK. AS THE SYSTEM MAKES ITS SOUTHERN MOST
APPROACH AT TAU 72, SURFACE INTENSITIES WILL CONTINUE INTENSIFYING
AS THE ENVIRONMENT REMAINS CONDUCIVE WITH LOW VERTICAL WIND SHEAR
OF LESS THAN 20 KTS, SEA SURFACE TEMPERATURES BETWEEN 29 C TO
30 C, AND A SUPPORTIVE TROPICAL UPPER-TROPOSPHERIC TROUGH (TUTT)
LOCATED TO THE NORTHEAST PROVIDING AN ADDITIONAL MECHANISM FOR
OUTFLOW ALOFT. AS TS 25W BEGINS ITS WEST-NORTHWEST TRACK AFTER TAU
96, THE SYSTEM WILL LOSE THE SUPPORT OF THE TUTT, INITIATING A
SLIGHT WEAKENING PHASE BY TAU 120 TO 60 KTS.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE REMAINS IN FAIR
AGREEMENT WITH A CROSS-TRACK SPREAD OF 70 NM BY TAU 48 JUST WEST OF
GUAM WITH NAVGEM BEING THE SINGLE OUTLIER LOCATED A FEW MILES
DISLOCATED TO THE NORTH FROM THE JTWC CONSENSUS. BY TAU 120, THE
CROSS-TRACK SPREAD DIVERGES SIGNIFICANTLY TO 230 NM. OVERALL, THE
JTWC TRACK CONSENSUS ILLUSTRATES A GENERALLY WESTWARD TRACK THROUGH
THE REMAINDER OF THE FORECAST PERIOD, LENDING MEDIUM CONFIDENCE
THROUGH TAU 72. AFTER TAU 72, CONFIDENCE BECOMES LOW AS MODEL
SOLUTIONS DIVERGE INTO TAU 120. THE INTENSITY MODEL GUIDANCE IS
ALSO IN GOOD AGREEMENT OVER THE NEXT 72 HOURS, INDICATING STEADY
INTENSIFICATION INTO TAU 48, HOWEVER, AFTER TAU 48, CONFIDENCE IN
THE INTENSITY FORECAST LESSENS AS JTWC INTENSITY SOLUTIONS VARY
GREATLY INTO TAU 96, ILLUSTRATING A RANGE OF 60 KTS BETWEEN TAU 96
AND TAU 120. THE COAMPS-TC ENSEMBLE INTENSITY PROBABILITY PRODUCT
INDICATES STEADY INTENSITIES INTO TAU 36, WHILE A WINDOW OF
MODERATE INTENSIFICATION OF LESS THAN 20 PERCENT BETWEEN TAU 36 AND
TAU 78 IS EXPECTED.

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