WDPN32 PGTW 010900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 19W (JEBI) WARNING NR 020//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 34.8N 142.3E
   INITIAL INTENSITY: 65 KTS
   GEOGRAPHIC REFERENCE: 227 NM EAST-SOUTHEAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 22 KTS
   SIGNIFICANT WAVE HEIGHT: 27 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS DEEP
CONVECTION OBSCURING WHAT WAS PREVIOUSLY AN EYE FEATURE AS THE
SYSTEM TRACKS INTO COOLER 26-27C WATERS. OCEAN HEAT CONTENT RAPIDLY
DECLINES AS THE SYSTEM TRACKS NORTHWARD OF THE KUROSHIO CURRENT.
THE NOTABLY FAST TRACK SPEED CONTINUES TO BE ENHANCED BY THE
CONSTRUCTIVE INFLUENCE OF A TROPICAL UPPER TROPOSPHERIC TROUGH
(TUTT) CELL TO THE WEST AND A SUBTROPICAL RIDGE (STR) TO THE 
SOUTHEAST. WATER VAPOR IMAGERY DEPICTS AN UPPER-LEVEL TROUGH THAT IS 
BEGINNING TO IMPACT THE NORTHWESTERN PERIPHERY OF TYPHOON (TY) 19W AS 
IT BECOMES SLIGHTLY ELONGATED ON A NORTHEAST-SOUTHWEST AXIS. MOIST
OUTFLOW IS PULLED NORTHWESTWARD WHILE DRY AIR ASSOCIATED WITH THE
TUTT ERODES THE SOUTHERN SEMICIRCLE OF THE SYSTEM. THE INITIAL
POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE OBSCURED
LOW-LEVEL CIRCULATION CENTER (LLCC) AND ELONGATED STRUCTURE OF THE
SYSTEM. THE INITIAL INTENSITY OF 65 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON THE DRY AIR ENTRAINMENT FROM THE SOUTH AND
INTRODUCTION OF COOLER WATERS NORTH OF THE KUROSHIO CURRENT,
SUPPLEMENTED BY THE AGENCY AND OBJECTIVE FIXES LISTED BELOW.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: A STR TO THE SOUTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T4.0 - 65 KTS
   RCTP: T4.0 - 65 KTS
   KNES: T4.5 - 77 KTS
   CIMSS ADT: 51 KTS AT 010530Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 5-10 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: STRONG POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: HIGH
   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 19W WILL CONTINUE TO BE DRIVEN
NORTHEASTWARD AS IT CONTINUES TO ROUND THE STR TO THE SOUTHEAST.
THE TRACK SPEED WILL CONTINUE TO INCREASE AS THE SYSTEM UNDERGOES
EXTRATROPICAL TRANSITION WHILE THE VORTEX SHALLOWS AND TY 19W
BECOMES EMBEDDED WITHIN THE JET. IN THE MEANTIME, EXTRATROPICAL
TRANSITION WILL BE INITIATED BY COOLER SEA SURFACE TEMPERATURES
BELOW 26C WITHIN THE FIRST 12 HOURS. BY TAU 24, AN UPPER-LEVEL
TROUGH ASSOCIATED WITH THE JET STREAM WILL SWEEP OVER THE
CIRCULATION, INTRODUCING BAROCLINIC FORCING. EXTRATROPICAL
TRANSITION WILL COMPLETE BY TAU 36 WHEN THE SYSTEM HAS FULLY
DEVELOPED FRONTS. AFTER TAU 0, THE INTENSITY WILL WEAKEN AS SHEAR
PICKS UP TO 25-30KTS AND INCREASES THROUGH THE END OF THE FORECAST
PERIOD.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN GOOD AGREEMENT
THAT THE SYSTEM WILL TRACK NORTHEASTWARD THROUGH THE END OF THE
FORECAST, AS REPRESENTED BY A 300NM SPREAD BY THE END OF THE
FORECAST PERIOD. THE ONLY OUTLIER IS GALWEM, WHICH TRACKS THE
SYSTEM IN A NORTH-NORTHEASTWARD DIRECTION BETWEEN TAU 24-36. THE
INTENSITY GUIDANCE ALSO IS IN GENERALLY GOOD AGREEMENT AS TO
CONSISTENT AND GRADUAL WEAKENING THROUGH THE END OF THE FORECAST
WITH THE EXCEPTION OF GFS, WHICH PREDICTS A SLIGHT INTENSIFICATION
THROUGH THE FIRST 12 HOURS.

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