WDPN32 PGTW 070300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 28W (HALONG) WARNING NR 011//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 26.9N 138.6E
   INITIAL INTENSITY: 80 KTS
   GEOGRAPHIC REFERENCE: 193 NM NORTHWEST OF IWO TO
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 27 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A CLEARING
EYE FEATURE BUILDING SYMMETRIC CONVECTION AROUND THE LOW-LEVEL
CIRCULATION CENTER (LLCC). COOLING CLOUD TOPS ON ANIMATED ENHANCED
INFRARED IMAGERY (EIR) REVEALS COOLING CLOUD TOPS INDICATIVE OF THE
INTENSIFICATION THAT TY 28W HAS UNDERGONE OVER THE LAST SIX HOURS.
THE SUBTROPICAL JET FLOWS ZONALLY TO THE NORTH OF TYPHOON (TY) 28W,
ENHANCING POLEWARD OUTFLOW WHILE EQUATORWARD OUTFLOW IS ENCOURAGED
BY STRAIGHT-LINE NORTHWESTERLY UPPER-LEVEL FLOW. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE AFOREMENTIONED
ANIMATED MSI. THE INITIAL INTENSITY OF 80 KTS IS ASSESSED WITH
MEDIUM CONFIDENCE BASED ON THE AGENCY AND OBJECTIVE FIXES LISTED
BELOW.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: A SUBTROPICAL RIDGE TO EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   RJTD: T4.5 - 77 KTS
   CIMSS ADT: 72 KTS AT 062030Z
   CIMSS AIDT: 73 KTS AT 062030Z
   CIMSS D-MINT: 75 KTS AT 061933Z
   CIMSS D-PRINT: 82 KTS AT 062300Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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 28W WILL GRADUALLY ROUND THE SUBTROPICAL
RIDGE TO THE EAST, FIRST CURVING NORTH-NORTHWESTWARD WHILE
APPROACHING THE RIDGE AXIS, FOLLOWED BUY A RECURVE TO THE
NORTH-NORTHEAST THROUGH TAU 48. THE TRACK SPEED WILL INCREASE AS
THE SYSTEM COMES UNDER THE INFLUENCE OF THE SUBTROPICAL JET TO THE
NORTH, INCREASING TRACK SPEED FROM SIGNIFICANTLY THROUGH TAU 96. AS
TY 28W APPROACHES THE BAROCLINIC ZONE TO THE NORTH BETWEEN TAU
48-72, THE SYSTEM WILL ACQUIRE EXTRATROPICAL QUALITIES BECOMING
VERTICALLY TILTED, COLD CORE, AND FRONTAL. FRONTOGENESIS WILL
CONTINUE THROUGH TAU 96, WHEN THE SYSTEM WILL BE CONSIDERED FULLY
EXTRATROPICAL. THE ENVIRONMENT WILL REMAIN HIGHLY FAVORABLE FOR
DEVELOPMENT OVER THE NEXT 36 HOURS WITH LOW VERTICAL WIND SHEAR,
ENHANCED UPPER-LEVEL DIVERGENCE, AND UNSEASONABLY WARM SEA SURFACE
TEMPERATURES ALONG THE KUROSHIO CURRENT. HOWEVER, COOL UPWELLING
FROM A COLD-CORE EDDY AND HIGH VERTICAL WIND SHEAR FROM THE
SUBTROPICAL JET WILL DOUBLE-DOWN TO INITIATE A WEAKENING TREND
FOLLOWING TAU 48. WEAKENING WILL GRADUALLY CONTINUE THROUGH
EXTRATROPICAL TRANSITION TO 50KTS BY THE END OF THE FORECAST
PERIOD.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN STRONG
AGREEMENT THAT TY 28W WILL RECURVE AROUND THE SUBTROPICAL RIDGE TO
THE EAST, INCREASING TRACK SPEED DURING EXTRATROPICAL TRANSITION.
THE CROSS-TRACK SPREAD AT TAU 96 IS 80NM. THE INTENSITY GUIDANCE IS
ALSO IN STRONG AGREEMENT, WITH RAPID INTENSIFICATION AIDS
INDICATING A PEAK BETWEEN 105-135KTS WITHIN THE NEXT 24-36 HOURS.
THE REMAINDER OF THE INTENSITY GUIDANCE FALLS MOSTLY IN LINE WITH
THE RAPID INTENSIFICATION AIDS, WITH THE EXCEPTION OF GFS, WHICH
PEAKS AT 95KTS.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   TRACK 72-120 HR: HIGH
   INTENSITY 00-72 HR: HIGH
   INTENSITY 72-120 HR: MEDIUM//
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