WDPN32 PGTW 010300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 19W (JEBI) WARNING NR 019//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 32.7N 141.7E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 185 NM SOUTH-SOUTHEAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 19 KTS
   SIGNIFICANT WAVE HEIGHT: 28 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TYPHOON (TY) 19W (JEBI) HAS RAPIDLY INTENSIFIED OVER THE LAST 24
HOURS, INCREASING INTENSITY FROM 40 KNOTS TO 70 KNOTS AS IT RACES
POLEWARD TO THE EAST OF JAPAN. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) DEPICTS SHOWS THAT TY 19W DEVELOPED A CLOUD-FILLED
EYE AROUND 302100Z, WHEN IT LIKELY REACHED PEAK INTENSITY. THE
LATEST MSI SHOWS THE EYE ALREADY BEGINNING TO FILL. A 302122Z WSF-M
37GHZ MICROWAVE IMAGE SHOWED A WELL-DEFINED MICROWAVE EYE FEATURE,
WITH THE UPPER-LEVEL MICROWAVE EYE TILTED A BIT TO THE NORTHEAST
UNDER MODERATE SOUTHWESTERLY SHEAR. THE INITIAL POSITION WAS
ASSESSED WITH HIGH CONFIDENCE BASED ON AN EXTRAPOLATION OF THE
MICROWAVE EYE NOTED ABOVE, AND THE RAGGED EYE IN THE MSI. A 302023Z
RCM-3 SAR PASS REVEALED AN ASYMMETRIC WIND FIELD, THOUGH IT HAS
EXPANDED ON THE WEST SIDE A MODEST AMOUNT. THE SAR RECORDED A LARGE
ARC OF 65KT OR HIGHER WINDS COMPLETELY ENCOMPASSING THE EASTERN
HEMISPHERE OF THE CIRCULATION AND A PEAK WIND OF 77 KNOTS. THE
ENVIRONMENT REMAINS GENERALLY FAVORABLE, THOUGH WILL NOT LAST AS SUCH
MUCH LONGER, AS SHEAR IS RAPIDLY PICKING UP. OTHERWISE, SSTS REMAIN
WARM AND OUTFLOW REMAINS VERY STRONG TO POLEWARD.

INITIAL WIND RADII BASIS: SAR DATA 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T3.5 - 55 KTS
   KNES: T4.0 - 65 KTS
   CIMSS ADT: 51 KTS AT 010030Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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: TY 19W (JEBI) WILL CONTINUE TRACKING
NORTH-NORTHEASTWARD FOR THE NEXT FEW HOURS AND ONCE IT REACHES THE
RIDGE AXIS, EXPECTED IMMINENTLY, WILL STEP ON THE GAS AND
ACCELERATE OFF TO THE NORTHEAST AS IT ROUNDS THE RIDGE. THE SYSTEM
HAS MOST LIKELY REACHED PEAK INTENSITY AT 302100Z, AND EVEN THOUGH
SHEAR WILL INCREASE FROM HERE ON OUT, THE WIND FIELD WILL TAKE TIME
TO SPIN DOWN. THUS, NO MAJOR CHANGE IN INTENSITY IS EXPECTED FOR
THE FIRST 12 HOURS OF THE FORECAST. WITHIN THE NEXT 12 TO 18 HOURS
HOWEVER, SHEAR IS FORECAST TO PICK UP TO OVER 30 KNOTS, WHICH WILL
DECAPITATE THE VORTEX AS IT STARTS EXTRATROPICAL TRANSITION BY TAU
12. THE SYSTEM WILL COMPLETE ETT BETWEEN TAU 24 AND 36 AS IT MOVES
UNDER A JET MAX AND DEVELOPS FRONTAL CHARACTERISTICS. 

MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE IS IN VERY TIGHT
AGREEMENT, BOTH IN TERMS OF CROSS- AND ALONG-TRACK SPREAD. THE
ANTICIPATED NORTH-NORTHWEST JOG DID NOT OCCUR AS EXPECTED, AND THUS
CPA TO YOKOSUKA HAS OPENED UP ONCE MORE TO 150NM. OVERALL, WITH THE
TIGHT GROUPING IN THE GUIDANCE, THERE IS HIGH CONFIDENCE TO THE
JTWC FORECAST TRACK. INTENSITY GUIDANCE IS ALSO IN GOOD AGREEMENT
WITH A STEADY INTENSITY THROUGH TAU 12 FOLLOWED BY RAPID WEAKENING
THROUGH ETT. THE JTWC FORECAST IS PLACED ON TOP OF THE HAFS-A
TRACKER WITH HIGH CONFIDENCE. 

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