WDPN31 PGTW 140900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 15W (MERBOK) WARNING 
NR 015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 29.8N 162.2E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 552 NM NORTHEAST OF MINAMI TORI SHIMA
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 15 KTS
   SIGNIFICANT WAVE HEIGHT: 31 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A WELL
DEFINED SYSTEM WITH MULTIPLE DEEP CONVECTIVE ELEMENTS ROTATING
AROUND THE LOW LEVEL CIRCULATION CENTER (LLCC) AND TIGHT LOW-LEVEL
AND DEEP CONVECTIVE BANDING IN ALL QUADRANTS. WORKING WITH VERY
LIMITED MICROWAVE IMAGERY, A 140148Z AMSR2 89GHZ COLOR COMPOSITE
MICROWAVE IMAGE INDICATES MULTIPLE CONCENTRIC CIRCLES AROUND THE
SYSTEMS CENTER, INDICATING THAT 15W IS STILL TRYING TO CONSOLIDATE
A CORE STRUCTURE. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON MSI AND AGENCY DVORAK FIX LOCATIONS. THE
INITIAL INTENSITY OF 70 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON ALL AGENCY DVORAK INTENSITY ESTIMATES INDICATING T4.0-T4.5
WHILE CIMSS ESTIMATES LAG SLIGHTLY BEHIND.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T4.5 - 77 KTS
   KNES: T4.0 - 65 KTS
   PHFO: T4.0 - 65 KTS
   CIMSS SATCON: 66 KTS AT 140236Z
   CIMSS ADT: 51 KTS AT 140640Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE RADIAL

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 15W (MERBOK) CONTINUES TO TRACK GENERALLY
NORTHWARD AROUND THE PERIPHERY OF THE STR TO THE EAST. OVER THE
NEXT 12 HOURS, TRACK SPEEDS WILL INCREASE AND THE SYSTEM WILL
TRANSITION TO A NORTH-NORTHEASTWARD HEADING. AS 15W CONTINUES
POLEWARD, IT WILL BEGIN TO RAPIDLY INTERACT WITH A PASSING
UPPER-LEVEL TROUGH PASSING SOUTH OF THE KAMCHATKA PENINSULA. AFTER
TAU 12 AND THROUGH THE FORECAST PERIOD AS THE SYSTEM RAPIDLY
PROGRESSES THROUGH EXTRA-TROPICAL TRANSITION, INTENSITIES WILL
CONTINUE TO INCREASE AS 15W BECOMES INCREASINGLY FRONTAL IN NATURE.
BY TAU 36, ETT WILL COMPLETE AS THE REMAINING TROPICAL
CHARACTERISTICS ARE EXTINGUISHED, AND THE NOW FRONTAL SYSTEM
CONTINUES TOWARDS THE ALEUTIAN ISLANDS, WITH A POTENTIAL MAX
INTENSITY OF 85 KNOTS. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN TIGHT AGREEMENT WITH THE
JTWC FORECAST TRACK AND IT HAS THEREFOR BEEN PLACED WITH HIGH
CONFIDENCE. RELIABLE MODEL INTENSITY GUIDANCE IS IN GOOD AGREEMENT,
WITH A NOTABLE SPREAD TAKING PLACE AFTER TAU 24 WITH COAMPS-TC
CONTINUING TO RAPIDLY INTENSIFY AND HWRF WEAKENING THE SYSTEM
AGGRESSIVELY. THE JTWC FORECAST INTENSITY HAS BEEN PLACED CLOSE TO
THE MULTI-MODEL CONSENSUS WITH MEDIUM CONFIDENCE. 

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