WDPN31 PGTW 270300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 19W (KULAP) WARNING NR 
006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 28.0N 141.9E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 195 NM NORTH OF IWO TO
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 17 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A 
CONSOLIDATING SYSTEM A DEEP CONVECTION BAND ON THE EASTERN
PERIPHERY WRAPPING INTO A PERSISTENT CONVECTIVE CLOUD STRUCTURE,
WHICH IS OBSCURING A LOW LEVEL CIRCULATION CENTER (LLCC). THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON VISIBLE
IMAGERY AND A PARTIAL METOP-B ASCAT PASS. THE INITIAL INTENSITY IS
ALSO PLACED WITH HIGH CONFIDENCE BASED ON THE AFOREMENTIONED
METOP-B ASCAT WHICH SHOWS UP TO 45 KNOT WIND BARBS ON THE EASTERN
PERIPHERY. ALONG WITH A BLEND OF THE AUTOMATED DVORAK ESTIMATES
INTENSITIES FROM CMISS ADT OF 39 KNOTS, WHILE SATCON SHOWS UP TO 49
KNOTS IN COMBINATION WITH AGENCY DVORAK INTENSITIES FROM PGTW T3.0,
RJTD T3.0, AND KNES T3.5.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE (STR) TO
THE NORTHEAST 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T3.0 - 45 KTS
   CIMSS SATCON: 49 KTS AT 262247Z
   CIMSS ADT: 39 KTS AT 262340Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: TS 19W (KULAP) IS FORECAST TO TRACK ALONG THE
OUTER PERIPHERY OF THE
SUBTROPICAL RIDGE (STR) TO THE NORTHEAST, AS THE SYSTEM CONTINUES
TO DO SO IT WILL ROUND THE RIDGE AXIS WITHIN THE NEXT 12 HOURS. AS
THIS OCCURS, A SHORTWAVE TROUGH CURRENTLY MOVING OVER NORTHERN
JAPAN WILL WEAKEN THE STR ALLOWING TS 19W TO RECURVE AND ACCELERATE
NORTHEASTWARD. AS THE SYSTEM TRANSITS NORTHEASTWARD, THE
ENVIRONMENTAL CONDITIONS WILL REMAIN FAVORABLE FOR 19W INTENSIFY TO
A MAXIMUM INTENSITY OF 65 KTS BY TAU 48. AFTER TAU 48, 19W WILL BEGIN 
TO INTERACT WITH THE SHORTWAVE TROUGH AND BEGIN TO BECOME EMBEDDED 
WITHIN THE MID-LATITUDE WESTERLIES AND BAROCLINIC ZONE. BY TAU 72, THE 
SYSTEM WILL COMPLETE EXTRA-TROPICAL TRANSITION (ETT) AS IT GAINS 
FRONTAL CHARACTERISTICS WHILE DECREASING IN INTENSITY DUE TO COOLER SEA 
SURFACE TEMPERATURE VALUES (25-26C) AND STRONG VERTICAL WIND SHEAR.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE ARE IN VERY GOOD THROUGH
TAU 36, WITH ONLY A 83 NM SPREAD IN MODEL TRACK SOLUTIONS. BY TAU
72 THE MODEL GUIDANCE INCREASES IN UNCERTAINLY WITH A GRADUALLY
SPREAD TO 400 NM. LIKELY DUE TO HOW NUMERICAL MODELS ARE HANDLING
LARGE SCALE SHORTWAVE UPPER LEVEL TROUGH INTERACTION WITH 19W.
THEREFORE, THE JTWC TRACK FORECAST IS ASSESSED WITH MEDIUM
CONFIDENCE TO ACCOUNT FOR THE CROSS TRACK SPREAD AT TAU 72. THE
INTENSITY FORECAST IS ASSESSED WITH LOW CONFIDENCE WITH GFS DECAY
SHIPS (DSHA) REPRESENTING THE LOW END OF GUIDANCE WITH A PEAK OF 50
KNOTS BY TAU 36, AND COAMPS-TC GUIDANCE UP TO 85 KNTS BY TAU 36.
THE JTWC INTENSITY FORECAST REMAINS CLOSE TO THE MULTI-MODEL
CONSENSUS WITH CLOSER TO THE GFS (AHNI) AND HWRF GUIDANCE
ESPECIALLY THROUGH TAU 48 . 

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