WDPN32 PGTW 021500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 06W (KHANUN) WARNING NR 026//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 26.2N 125.7E
   INITIAL INTENSITY: 100 KTS
   GEOGRAPHIC REFERENCE: 114 NM WEST OF KADENA AB
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 37 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A WELL
DEFINED 20NM EYE AND DEEP CONVECTIVE BANDING FEATURES IN ALL
QUADRANTS. AS THE SYSTEM SLOWS DOWN, A SLIGHT TROCHOIDAL WOBBLE IS
ONCE AGAIN EVIDENT.  A RECENT 020830Z SSMIS 91GHZ MICROWAVE IMAGE
REVEALS A TIGHT INNER EYEWALL WITH A PRONOUNCED, ROUGHLY 90NM MOAT,
BEYOND WHICH IS THE SECONDARY EYEWALL. THIS RECENT MICROWAVE
IMAGERY ALONG WITH INCREASING MICROWAVE PROBABILITY OF EYEWALL
REPLACEMENT CYCLE (M-PERC) VALUES, INDICATE AN EYEWALL REPLACEMENT
CYCLE (ERC) IS LIKELY UNDERWAY. THE INITIAL POSITION IS PLACED WITH
HIGH CONFIDENCE BASED ON EIR AND SSMIS IMAGERY. THE INITIAL
INTENSITY OF 100 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON A
NEARLY COMPLETE CONSENSUS AMONGST AGENCY DVORAK AND AUTOMATED
INTENSITY FIXES THAT REFLECT PERSISTENT INTENSITY AND EVEN SLIGHT
INTENSIFICATION. THIS STAND IN STARK CONTRAST TO A RECENT 020859Z
SMAP PARTIAL PASS AND 020945Z SAR PASS WHICH BOTH SHOWED A PEAK
INTENSITY OF 85-91 KTS. BASED ON THIS DISSONANCE, THE CONFIDENCE IN
THE INITIAL INTENSITY IS MEDIUM.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: A DEEP-LAYER SUBTROPICAL RIDGE (STR)
CENTERED OVER THE YELLOW SEA TO THE NORTH AND A NEAR-EQUATORIAL
(NER) CENTERED TO THE SOUTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.0 - 115 KTS
   RJTD: T5.5 - 102 KTS
   RCTP: T5.5 - 102 KTS
   KNES: T5.5 - 102 KTS
   CIMSS ADT: 102 KTS AT 021130Z

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

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 06W (KHANUN) IS FORECAST TO CONTINUE
WEST-NORTHWESTWARD OVER THE NEXT 24 HOURS. DURING THAT TIME, THE
ONGOING ERC WILL INDUCE LIMITED SHORT TERM WEAKENING THAT WILL
EVENTUALLY BE EXACERBATED BY UPWELLING OF COOLER WATERS BENEATH
06W. THIS UPWELLING TAKES PLACE NEAR TAU 24, AS THE STR OVER THE
YELLOW SEA BEGINS TO SHIFT WESTWARD AND BLOCKS ANY FURTHER MOVEMENT
TOWARDS MAINLAND CHINA. AS TRACK SPEEDS GRIND TO A HALT, UPWELLING
BEGINS TO QUICKLY WEAKEN THE SYSTEM. BY TAU 36, 06W IS FORECAST TO
SHARPLY TURN GENERALLY EAST-NORTHEASTWARD EVENTUALLY PICKING UP
SPEED WHILE CONTINUING TO WEAKEN. BY TAU 72, THE SYSTEM WILL HAVE
WEAKENED TO AROUND 65KTS AS IT ONCE AGAIN PASSES KADENA AB. BEYOND
TAU 100, HAS SEEN SOME OF THE GREATEST RUN TO RUN VARIABILITY,
THANKS IN PART TO RIDGING, OR LACK THEREOF, THAT DEVELOPS TO THE
NORTHEAST OF THE SYSTEM. FOR THE TIME BEING, THE PREPONDERANCE OF
MODEL GUIDANCE BOTH DETERMINISTIC AND ENSEMBLE, INDICATES A
PERSISTENT EAST-NORTHEASTERLY COURSE FOLLOWING TAU 36 AND THROUGH
THE CURRENT FORECAST PERIOD.

MODEL DISCUSSION: WITH THE EXCEPTION OF NVGM AND HWRF, NUMERICAL
MODEL GUIDANCE IS IN FAIR AGREEMENT THROUGH TAU 36 WITH THE BULK OF
THE GUIDANCE INDICATING A SLOW APPROACH TO 124E BEFORE SHARPLY
TURNING EAST-NORTHEASTWARD. NVGM AND HWRF EXECUTE THEIR TURNS
SOONER AND MORE DRAMATICALLY, EVENTUALLY BEING JOINED BY COAMPS-TC
(NVGM AND GFS), THESE MEMBERS ALL PASS WITHIN 15-40NM OF KADENA AB.
THE REMAINING MODEL GUIDANCE MORE CLOSELY FOLLOWS THE JTWC TRACK
FORECAST MAINTAINING A GREATER CPA TO KADENA. WITH THE EXCEPTION OF
JGSM WHICH TARGETS SASEBO, ALL OTHER MEMBERS CONTINUE AN
EAST-NORTHEASTERLY HEADING FOLLOWING TAU 36 AND THROUGH TAU 120.
FOR ALL OF THESE REASONS THE JTWC TRACK FORECAST IS PLACED
INITIALLY WITH MEDIUM CONFIDENCE AND WITH LOW CONFIDENCE
THEREAFTER. RELIABLE MODEL INTENSITY GUIDANCE IS IN FAIR AGREEMENT
WITH ALL MEMBERS INDICATING SLIGHT WEAKENING THROUGH TAU 24 AND
MORE DRAMATIC WEAKENING THEREAFTER, WITH MINIMAL DEVIATION FROM THE
MULTI-MODEL CONSENSUS. FOR THIS REASON THE JTWC INTENSITY FORECAST
IS PLACED WITH OVERALL MEDIUM CONFIDENCE.

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