WDPN31 PGTW 280900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 19W (KULAP) WARNING NR 011//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 33.2N 147.7E
   INITIAL INTENSITY: 65 KTS
   GEOGRAPHIC REFERENCE: 393 NM EAST-SOUTHEAST OF NARITA AIRPORT
   MOVEMENT PAST 6 HOURS: EAST-NORTHEASTWARD AT 24 KTS
   SIGNIFICANT WAVE HEIGHT: 35 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
NOW TYPHOON KULAP HAS QUICKLY CONSOLIDATED AND INTENSIFIED, AND NOW
CAN BE SAFELY SAID TO HAVE REACHED MINIMAL TYPHOON STRENGTH.
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS DEEP
CONVECTIVE BANDS FORMING UP ON THE WEST SIDE AND SLIDING UPSHEAR TO
THE SOUTH OF THE SYSTEM. ENHANCED INFRARED IMAGERY SUGGESTS
DEVELOPMENT OF A RAGGED EYE FEATURE AS WELL. A 280340Z AMSR2 37GHZ
MICROWAVE IMAGE SHOWED WELL DEFINED SPIRAL BANDS OF DEEP CONVECTION
WRAPPING INTO A 35NM RAGGED MICROWAVE EYE FEATURE. EXTRAPOLATION OF
THE MICROWAVE EYE FEATURE PROVIDED HIGH CONFIDENCE TO THE INITIAL
POSITION. AGENCY FIXES ARE PREDOMINANTLY AT T3.5, WITH THE
EXCEPTION OF KNES, WHICH DERIVED A T4.5 USING THE EYE METHOD. THE
AMSR2 WINDSPEED PRODUCT SHOWS SOME VALUES UP TO 70 KNOTS IN THE
NORTHWEST QUADRANT UNDER THE DEEPEST CONVECTION, WHICH LENT SUPPORT
TO INCREASE THE INITIAL INTENSITY TO 65 KNOTS WITH MEDIUM
CONFIDENCE. CIMSS ANALYSIS SUGGEST 40 PLUS KNOTS OF SHEAR OVER THE
SYSTEM, BUT CLEARLY IT HAS BEEN ABLE TO FIGHT BACK AGAINST THIS AND
THE RELATIVE SHEAR IS OBVIOUSLY LOWER AS THE SHEAR VECTOR IS IN
PHASE WITH THE STORM MOTION. HWRF SOUNDINGS INDICATE A MAXIMUM
SHEAR VALUE IN THE 15-20 KNOT RANGE WHICH SEEMS REASONABLE BASED ON
THE IMPROVING STRUCTURE. OTHERWISE THE ENVIRONMENT IS GENERALLY
FAVORABLE WITH ROBUST POLEWARD OUTFLOW AND WARM (27-28C) SSTS.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: NORTHWEST PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) TO THE EAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T3.5 - 55 KTS
   KNES: T4.5 - 77 KTS
   CIMSS SATCON: 66 KTS AT 280317Z
   CIMSS ADT: 53 KTS AT 280540Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15-20 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: MID-LEVEL DRY AIR TO THE SOUTH

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING. HOWEVER THE FORECAST LENGTH
HAS BEEN CUT TO 24 HOURS. 

FORECAST DISCUSSION: THERE IS NO SIGNIFICANT CHANGE EXPECTED IN THE
FORECAST TRACK THROUGH THE FORECAST PERIOD. TYPHOON KULAP WILL
CONTINUE TO RACE NORTHEASTWARD THROUGH THE SHORT FORECAST (24
HOURS) ALONG THE TIGHTENING GRADIENT BETWEEN THE STEERING RIDGE TO
THE EAST AND A DEEP TROUGH APPROACHING FROM THE WEST. THE SYSTEM
HAS ALREADY STARTED TO FEEL SOME OF THE EFFECTS OF THE APPROACHING
MAJOR SHORTWAVE TROUGH, THE AXIS OF WHICH IS CURRENTLY MOVING INTO
THE SEA OF JAPAN, THOUGH THE SYSTEM REMAINS A WARM-CORE TROPICAL
CYCLONE. EXTRATROPICAL TRANSITION IS EXPECTED TO BEGIN IN EARNEST
WITHIN THE NEXT 12 HOURS, AS THE TROUGH TO WEST BECOMES NEGATIVELY
TILTED, AND TYPHOON KULAP MOVES INTO PHASE WITH THE TROUGH, MOVES
INTO THE RIGHT ENTRANCE REGION (RER) OF A 150 KNOT 200MB JET MAX,
AND STARTS TO EXPERIENCE STRONG THERMAL ADVECTION AND
FRONTOGENESIS. HOWEVER, THE SYSTEM IS EXPECTED TO RETAIN ITS
WARM-CORE PROPERTIES, TRANSITIONING VERY QUICKLY AS AN INSTANT WARM
CORE SECLUSION, ALL THE WHILE CONTINUING TO INTENSIFY DUE TO THE
EXCEPTIONALLY STRONG BAROCLINIC FORCING. 

MODEL DISCUSSION: NUMERICAL TRACK GUIDANCE IS IN VERY TIGHT
AGREEMENT THROUGH THE DURATION OF THE FORECAST PERIOD WITH ONLY
MINIMAL CROSS AND ALONG-TRACK SPREAD IN THE CONSENSUS MEMBERS,
GIVING HIGH CONFIDENCE TO THE JTWC FORECAST TRACK. INTENSITY
GUIDANCE IS IN GOOD AGREEMENT AS WELL THAT THE SYSTEM WILL IN FACT
INTENSIFY AS IT TRANSITIONS, WITH COAMPS-TC, HWRF, GFS AND
DECAY-SHIPS (GFS) INDICATING A PEAK BETWEEN 75 AND 80 KNOTS BY TAU
24, PROVIDING HIGH CONFIDENCE TO THE JTWC INTENSITY FORECAST. 

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