WDPN33 PGTW 260900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 25W (NEOGURI) WARNING NR 
032//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 32.1N 153.6E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 719 NM EAST-SOUTHEAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 1 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A COMPACT
CIRCULATION WITH LOW-LEVEL CLOUD BANDS TIGHTLY WRAPPING INTO THE 
CENTER AND CONVECTION SLIGHTLY OFFSET TO THE NORTH, REVEALING A
PARTIALLY EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC). TROPICAL
STORM (TS) 25W HAS SOMEHOW MAINTAINED INTENSITY OVER THE PAST 6
HOURS, DESPITE A MARGINALLY FAVORABLE ENVIRONMENT CHARACTERIZED BY
WEAK EQUATORWARD OUTFLOW ALOFT, UPWELLING CAUSED BY THE STORM'S
QUASI-STATIONARY MOVEMENT, AND DRY AIR ENTRAINMENT, OFFSET BY WARM
(28-29 C) SEA SURFACE TEMPERATURES AND LOW (5-10 KTS) VERTICAL WIND
SHEAR. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON
THE PARTIALLY EXPOSED LLCC IN ANIMATED MSI. THE INITIAL INTENSITY
IS PLACED WITH MEDIUM CONFIDENCE BASED ON A 25030307 AMSR-2
WINDSPEED IMAGE REVEALING A SMALL PATCH OF 50-55KT WINDS CONFINED
TO THE SOUTHEASTERN QUADRANT, AND CORROBORATED BY THE AGENCY DVORAK
INTENSITY ESTIMATES AND OBJECTIVE INTENISTY AIDS LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: COMPETING STEERING ENVIRONMENT, WITH
SUBTROPICAL RIDGES (STR) FLANKING THE SYSTEM TO THE EAST AND WEST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T3.5 - 55 KTS
   CIMSS SATCON: 54 KTS AT 260237Z
   CIMSS ADT: 37 KTS AT 260220Z
   CIMSS AIDT: 41 KTS AT 260220Z
   CIMSS D-MINT: 44 KTS AT 260304Z
   CIMSS D-PRINT: 48 KTS AT 260500Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: WEAK EQUATORWARD
   OTHER FACTORS: UPWELLING AND DRY AIR ENTRAINMENT

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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 REMAINS PINCHED BETWEEN TWO COMPETING
SUBTROPICAL RIDGES POSITIONED TO THE EAST AND WEST OF THE STORM. 
NEITHER RIDGE IS DOMINATING THE STEERING ENVIRONMENT AND HAS CAUSED 
25W TO REMAIN QUASI-STATIONARY OVER THE PAST 12 HOURS. 25W IS 
FORECAST
TO MOSEY EAST-SOUTHEASTWARD BETWEEN TAUS 0-12, BEFORE THE EASTERN
RIDGE BUILDS AN EXTENDED SOUTHERN PERIPHERY AROUND TAU 24 AND
CAUSES 25W TO FINALLY GAIN SPEED AND TRACK NORTHEASTWARD. 25W IS
EXPECTED TO ENTER UNDER INFLUENCE OF THE MID-LEVEL JET AT TAU 48,
BEGINNING ITS EXTRATROPICAL TRANSITION (ETT) AND RAPIDLY
ACCELERATING TO THE NORTHEAST. ETT IS EXPECTED TO BE COMPLETE BY
TAU 72. REGARDING INTENSITY, 25W IS EXPECTED TO INTENSIFY SLIGHTLY
FROM 55 KTS TO 60 KTS BETWEEN TAUS 12-24. 25W WILL FURTHER
INTENSIFY AS IT BEGINS TO BE INFLUENCED BY THE JET, REACHING A PEAK
OF 75KTS AT TAU 48. 25W WILL THEN WEAKEN AGAIN BY TAU 72, AFTER
COMPLETING ETT DUE TO THE EXTREME VERTICAL WIND SHEAR AND DRY AIR.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN STRONG
AGREEMENT THROUGH THE FORECAST PERIOD, WITH ONLY MINOR VARIATIONS
IN TRACK SPEED OCCURRING THROUGHOUT. AS A RESULT, THE JTWC IS
PLACED WITH HIGH CONFIDENCE. RELIABLE INTENSITY GUIDANCE IS IN
MODERATE AGREEMENT, WITH MOST MODELS PREDICTING 25W REACHING PEAK
INTENSITY AT TAU 48, HOWEVER, THE PEAK INTENSITIES RANGE FROM GFS
AT 60 KTS TO ECMWS AT 95 KTS. THE JTWC INTENSITY FORECAST HEDGES TO
THE MORE CONSERVATIVE SIDE, PLACED SLIGHTLY LOWER THAN THE
MULTI-MODEL CONSENSUS MEAN WITH MEDIUM CONFIDENCE.

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