WDPS31 PGTW 282100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 23P (URMIL) WARNING NR 
009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 22.1S 175.1E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 304 NM SOUTHWEST OF SUVA, FIJI
   MOVEMENT PAST 6 HOURS: EAST-SOUTHEASTWARD AT 16 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE (TC) 23P (URMIL) AS A GRADUALLY DETERIORATING CIRCULATION,
COMPLETELY OBSCURED BY A PERSISTENT CENTRAL DENSE OVERCAST (CDO)
FEATURE. SMALL POCKETS OF DEEP CONVECTION WITH OBSERVABLE
OVERSHOOTING TOPS CONTINUE TO FLARE, HOWEVER, HAVE BECOME MORE
DISORGANIZED WITHIN THE PAST SIX HOURS. ENVIRONMENTAL CONDITIONS
ARE MARGINALLY UNFAVORABLE WITH HIGH VERTICAL WIND SHEAR (25-30
KTS), SEA SURFACE TEMPERATURES BETWEEN 27 C AND 28 C, AND MODERATE
POLEWARD OUTFLOW. THE INITIAL POSITION IS PLACED WITH MEDIUM
CONFIDENCE BASED ON 281739Z 91 GHZ SSMIS MICROWAVE IMAGERY. THE
INITIAL INTENSITY OF 55 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED
ON 281757Z RCM-2 DATA INDICATING A VMAX MEAN OF 60 KTS AROUND THE
WESTERN AND NORTHERN QUADRANTS, COMBINED WITH SUBJECTIVE AGENCY
DVORAK ESTIMATES AND CIMSS OBJECTIVE INTENSITY ESTIMATES LISTED
BELOW.

INITIAL WIND RADII BASIS: 281325 AMSR2 DATA

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) POSITIONED
DIRECTLY TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   PHFO: T4.5 - 77 KTS
   CIMSS SATCON: 55 KTS AT 281331Z
   CIMSS ADT: 55 KTS AT 281730Z
   CIMSS AIDT: 61 KTS AT 281730Z
   CIMSS D-MINT: 45 KTS AT 281646Z
   CIMSS D-PRINT: 59 KTS AT 281730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 25-30 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: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 23P (URMIL) WILL
CONTINUE SOUTHEASTWARD FOR THE REMAINDER OF THE FORECAST PERIOD
UNDER THE INFLUENCE OF THE SUBTROPICAL RIDGE (STR) POSITIONED TO
THE EAST. MODEL GUIDANCE SUGGESTS A BRIEF WINDOW OF SLIGHT
INTENSIFICATION TOWARD A MAXIMUM OF 60 KTS BY TAU 12, THOUGH A
MARGINALLY UNFAVORABLE ENVIRONMENT MAY RESULT IN A FLAT-LINED
INTENSITY OVER THE NEXT 24 HOURS, NEAR 55 KTS. TC 23P HAS RECENTLY
STARTED SUBTROPICAL TRANSITION, INTERACTING WITH THE MID-LATITUDE
LONGWAVE PATTERN WHILE INJECTING A SIGNIFICANT AMOUNT OF DRY AIR
FROM THE WEST, RESULTING IN AN ELONGATED LLCC AND SLIGHTLY TILTED
VERTICAL STRUCTURE. TC 23P IS FORECASTED TO COMPLETE SUBTROPICAL
TRANSITION BY TAU 24 WITH A MAXIMUM SURFACE INTENSITY NEAR 45 KTS. 

MODEL DISCUSSION: CROSS-TRACK SPREAD AMONG MODEL GUIDANCE IS
UNDER 30 NM THROUGHOUT THE FORECAST PERIOD. THE JTWC FORECASTED
TRACK IS PLACED CLOSE TO THE MULTI MODEL CONSENSUS WITH HIGH
CONFIDENCE. INTENSITY SPREAD IS 15-20 KTS AT TAU 12, WITH HAFS-A
AND GFS IS STILL DEPICTING A SLIGHT INCREASE IN INTENSITY BEFORE THE
WEAKENING PHASE, DEPICTED BY ALL NUMERICAL MODEL SOLUTIONS
FOLLOWING TAU 12. THE JTWC FORECASTED INTENSITY LIES SLIGHTLY BELOW
THE MULTI MODEL CONSENSUS WITH MEDIUM CONFIDENCE. 

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   INTENSITY 00-72 HR: MEDIUM//
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