WDPN31 PGTW 280300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 20W (MINDULLE) WARNING NR 023//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 21.0N 136.2E
   INITIAL INTENSITY: 95 KTS
   GEOGRAPHIC REFERENCE: 362 NM SOUTHWEST OF IWO TO
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 45 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS AN IMPROVING
SYSTEM WITH ROBUST RADIAL OUTFLOW AND A RAGGED EYE FEATURE. TY 20W
CONTINUES TO TRACK GENERALLY NORTHWARD WITHIN A FAVORABLE
ENVIRONMENT OF WARM SEA SURFACE AND LOW VERTICAL WIND SHEAR. THE
INITIAL INTENSITY IS ASSESSED AT 95 KTS, SLIGHTLY HIGHER THAN THE
PGTW CURRENT INTENSITY ESTIMATE OF 5.0(90 KTS), AND IS HEDGED
SLIGHTLY LOWER THAN ADT (102 KTS). THE INITIAL POSITION IS BASED ON
THE RAGGED EYE FEATURE IN MSI AND IS SUPPORTED BY MULTIPLE AGENCY
FIX POSITIONS.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE BUILDING TO THE
SOUTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   RJTD: T6.0 - 115 KTS
   KNES: T5.0 - 90 KTS
   CIMSS SATCON: 93 KTS AT 272232Z
   CIMSS ADT: 102 KTS AT 272340Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: HIGH

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TY 20W WILL CONTINUE A GENERALLY NORTHWARD
TRACK AND THEN TURN NORTHEASTWARD AFTER TAU 36 AS THE SUBTROPICAL
RIDGE BUILDING TO THE SOUTHEAST TAKES A MORE NORTHEAST-SOUTHWEST
ORIENTATION. AFTER TAU 48, THE SYSTEM WILL ACCELERATE ON ITS
NORTHEASTWARD TRACK AS A MID-LATITUDE TROUGH APPROACHES FROM THE
WEST. AS THE EYEWALL CONTINUES TO CONSTRICT FOLLOWING THE
COMPLETION OF AN EYEWALL REPLACEMENT CYCLE AND THE SYSTEM CONTINUES
TO TRACK, TY 20W WILL CONTINUE TO INCREASE IN INTENSITY REACHING A
PEAK OF 110 KTS AROUND TAU 36. AFTERWARDS, INCREASING VERTICAL WIND
SHEAR AND A DRY AIR MASS TO THE WEST WILL BEGIN TO WEAKEN THE
SYSTEM, REACHING 80 KTS BY TAU 96. AT THIS POINT, TY 20W WILL BEGIN
TO INTERACT WITH THE BAROCLINIC ZONE AND BEGIN EXTRATROPICAL
TRANSITION (ETT) WHICH IT WILL COMPLETE NO LATER THAN TAU 120.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN VERY GOOD
AGREEMENT WITH ONLY A 50 NM CROSS-TRACK SPREAD AT TAU 48, AND ONLY
INCREASING TO 140 NM AT TAU 120. HOWEVER, THE ALONG-TRACK SPREAD
DOES BEGIN TO INCREASE AT TAU 96 AS MODELS BEGIN TO DISAGREE ON
TRACK SPEED AS THE SYSTEM UNDERGOES ETT. INTENSITY GUIDANCE IS ALSO
IN GOOD AGREEMENT, WITH ALMOST ALL MODELS SHOWING AN INCREASE IN
INTENSITY PEAKING BY TAU 48 FOLLOWED BY A DECREASING TREND FOR THE
REMAINDER OF THE FORECAST. THE FORECAST INTENSITY IS THEREFORE
PLACED CLOSE TO CONSENSUS.

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