WDPN33 PGTW 260300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 25W (NEOGURI) WARNING NR 
031//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 32.0N 153.7E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 468 NM NORTH OF MINAMI TORI SHIMA
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 28 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL STORM (TS) 25W HAS SLOWED SIGNIFICANTLY WHILE MAINTAINING
INTENSITY OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) DEPICTS A COMPACT CORE OF CENTRAL CONVECTION, WITH
LOW-LEVEL CLOUD LINES WRAPPING TIGHTLY INTO THE SYSTEM. A 252309Z
MHS 89GHZ MICROWAVE IMAGE DEPICTS LIMITED CURVED BANDING OVER THE
SOUTHEASTERN QUADRANT, WITH EXPOSED SHALLOW BANDING ELSEWHERE. THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE MSI.
THE INITIAL INTENSITY OF 60 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON A RECENT 251950Z SAR IMAGE SHOWING 60-65 KNOT WINDS. CIMSS
OBJECTIVE INTENSITY ESTIMATES REMAIN TOO LOW.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: COMPETING STEERING INFLUENCE, WITH A
SUBTROPICAL RIDGE TO THE WEST AND TO THE EAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T3.5 - 55 KTS
   CIMSS ADT: 35 KTS AT 252020Z
   CIMSS AIDT: 41 KTS AT 252020Z
   CIMSS D-PRINT: 47 KTS AT 260000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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 EFFECTIVELY TRAPPED BETWEEN TWO
COMPETING SUBTROPICAL STEERING RIDGES. THEREFORE, THE TRACK MOTION
HAS SLOWED AND IS EXPECTED TO BECOME QUASI-STATIONARY THROUGH TAU
12. CONSEQUENTLY, THE SYSTEM IS EXPECTED TO UPWELL COOLER WATER AND
MAY WEAKEN SLIGHTLY. AFTER TAU 12, A MAJOR SHORTWAVE TROUGH IS
FORECAST TO DEEPEN EAST OF HONSHU, WEAKENING THE SUBTROPICAL RIDGE
AND ALLOWING THE SYSTEM TO GRADUALLY ACCELERATE EAST-NORTHEASTWARD
TO NORTHEASTWARD. TS 25W WILL BEGIN EXTRA-TROPICAL TRANSITION (ETT)
AS IT INTERACTS WITH THE MIDLATITUDE WESTERLIES AND FRONTAL ZONE
BETWEEN TAU 36 AND TAU 48. STRONG UPPER-LEVEL SUPPORT WILL ALLOW
THE SYSTEM TO DEEPEN RAPIDLY AS A MIDLATITUDE BAROCLINIC LOW, WITH
INTENSITY FORECAST TO REACH 70-75 KNOTS AS IT COMPLETES ETT BY TAU
60 TO TAU 72. 

MODEL DISCUSSION: DETERMINISTIC AND PROBABILISTIC MODEL GUIDANCE IS
IN GOOD AGREEMENT LENDING MEDIUM CONFIDENCE TO THE JTWC TRACK
FORECAST. RELIABLE INTENSITY GUIDANCE SUPPORTS THE JTWC INTENSITY
FORECAST WITH MEDIUM CONFIDENCE.  

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