WDPN33 PGTW 201500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 25W (NEOGURI) WARNING NR 009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 26.2N 155.0E
   INITIAL INTENSITY: 95 KTS
   GEOGRAPHIC REFERENCE: 132 NM NORTH-NORTHEAST OF MINAMI TORI
SHIMA
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
COMPACT TYPHOON (TY) SLOWLY TRACKING WEST-NORTHWESTWARD WITH SLIGHT
TROCHOIDAL MOTION. AN EARLIER ARCTIC WEATHER SATELLITE AWR 89GHZ
MICROWAVE IMAGER REVEALS THE COMPACT CONVECTIVE BANDING SURROUNDING
A SMALL MICROWAVE EYE. TY 25W HAS CONTINUED TO RAPIDLY INTENSIFY IN
A HIGHLY FAVORABLY ENVIRONMENT AND IS NOW ASSESSED TO BE 95KTS. THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE
AFOREMENTIONED ANIMATED EIR AND EXTRAPOLATION FROM A 201053Z
METOP-B ASCAT IMAGE REVEALING A DISTINCT LOW-LEVEL CIRCULATION
CENTER. THE INITIAL INTENSITY OF 95 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON THE SAME ASCAT IMAGE WHILE SUPPORTED BY THE
AGENCY AND OBJECTIVE FIXES LISTED BELOW.

INITIAL WIND RADII BASIS: 201053Z METOP-B ASCAT DATA 

CURRENT STEERING MECHANISM: A COMPETING STEERING ENVIRONMENT
BETWEEN TWO RIDGES

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.0 - 115 KTS
   RJTD: T6.0 - 115 KTS
   RCTP: T6.5 - 127 KTS
   KNES: T6.0 - 115 KTS
   CIMSS SATCON: 94 KTS AT 200754Z
   CIMSS ADT: 84 KTS AT 201130Z
   CIMSS AIDT: 93 KTS AT 201130Z
   CIMSS D-MINT: 105 KTS AT 201150Z
   CIMSS D-PRINT: 101 KTS AT 201230Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD AND 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: TY 25W WILL CURVE NORTHWESTWARD ALONG THE
SOUTHERN PERIPHERY OF A SUBTROPICAL RIDGE OVER THE NEXT 36 HOURS
WHILE THE STEERING ENVIRONMENT BECOMES INCREASINGLY COMPLEX. THE
SUBTROPICAL RIDGE TO THE WEST WILL BUILD OVER THE NEXT 36 HOURS,
SLOWING THE TRACK OF TY 25W AND CAUSING IRREGULAR TRACK MOTION
UNTIL TAU 48. AROUND TAU 48, A DEEP-LAYER TROUGH WILL BREAK DOWN
THE RIDGE TO THE WEST, ALLOWING FOR TY 25W TO TRACK NORTHEASTWARD
FOR THE REMAINDER OF THE FORECAST PERIOD. BY TAU 96, TY 25W WILL
BEGIN TO BECOME EMBEDDED WITHIN THE APPROACHING UPPER-LEVEL TROUGH,
AND BEGIN EXTRATROPICAL TRANSITION. THE ENVIRONMENT WILL BE
FAVORABLE OVER THE NEXT 48 HOURS FOR INTENSIFICATION WHILE IN WARM
SEA SURFACE TEMPERATURES, LOW VERTICAL WIND SHEAR, AND STRONG
UPPER-LEVEL DIVERGENCE. VERTICAL WIND SHEAR WILL INCREASE
UNFAVORABLY AFTER TAU 72 DUE TO THE APPROACHING TROUGH.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS SPREAD,
BIFURCATING AFTER TAU 36. SINCE THE LAST CYCLE, MORE OF THE JTWC
MULTI-MODEL CONSENSUS MEMBERS CURVE NORTHEASTWARD. THERE IS A
BIFURCATION SCENARIO WITHIN THE JTWC MULTI-MODEL CONSENSUS CENTERED
AROUND THE QUASI-STATIONARY PERIOD AT TAU 48-72 AND THE BREAKDOWN
OF THE RIDGE TO THE WEST. GIVEN THAT THERE IS SIGNIFICANT
UNCERTAINTY IN THE TRACK GUIDANCE, AND THAT THE DEEP-LAYER TROUGH
MAY NOT BREAK DOWN THE RIDGE OVER JAPAN, THE TRACK AND INTENSITY
FORECAST MAY DEVIATE FROM THE CURRENT FORECAST GREATLY DUE TO A
LONGER QUASI-STATIONARY PERIOD. THE INTENSITY GUIDANCE IS IN BETTER
AGREEMENT, BUT AS MENTIONED, IS ENTIRELY DEPENDENT ON THE TRACK
GUIDANCE ABOVE. 

FORECAST CONFIDENCE:
   TRACK 00-72 HR: LOW
   TRACK 72-120 HR: LOW
   INTENSITY 00-72 HR: LOW
   INTENSITY 72-120 HR: LOW//
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