WDPN31 PGTW 030300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (AERE) WARNING NR 
011//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 27.8N 127.2E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 84 NM NORTH-NORTHWEST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A FULLY
EXPOSED LOW-LEVEL CIRCULATION DEVOID OF DEEP CONVECTION. THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON RECENT
POSITION FIXES FROM PGTW AND RJTD AND MULTISPECTRAL SATELLITE
IMAGERY. THE INITIAL INTENSITY OF 35 KTS, CONSERVATIVELY SET A BIT
HIGHER THAN SUBJECTIVE DVORAK CURRENT INTENSITY ESTIMATES INDICATE,
IS ASSESSED WITH MEDIUM CONFIDENCE. ANIMATED WATER VAPOR IMAGERY
AND ATMOSPHERIC MOTION VECTORS SHOW A NARROW TROPICAL UPPER
TROPOSPHERIC TROUGH PERSISTING DIRECTLY OVER THE LOW-LEVEL
CIRCULATION.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE TO THE
EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T2.0 - 30 KTS
   CIMSS ADT: 25 KTS AT 022350Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 20-25 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: WEAK POLEWARD
   OTHER FACTORS: UPPER TROPOSPHERIC TROUGH DIRECTLY OVER THE
LOW-LEVEL CIRCULATION

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: OVER THE NEXT 48 HOURS, TS 05W IS EXPECTED TO
TRACK POLEWARD AND TURN EASTWARD TOWARD MAINLAND JAPAN AS IT
FOLLOWS THE FLOW ALONG THE WESTERN AND NORTHERN PERIPHERIES OF THE
CURRENT SUBTROPICAL STEERING RIDGE CURRENTLY SITUATED TO THE EAST. 
THE SYSTEM WILL CONTEND WITH A HOSTILE ENVIRONMENT THROUGHOUT THE
FORECAST PERIOD. A PERSISTENT UPPER-LEVEL TROUGH WILL INDUCE
UNFAVORABLE VERTICAL WIND SHEAR AND SUBSIDENCE ALOFT IN THE
NEAR-TERM, AND LAND INTERACTION AND VERTICAL WIND SHEAR INDUCED BY
A MID-LATITUDE SHORTWAVE TROUGH WILL LIKELY INFLUENCE THE SYSTEM
DURING THE EXTENDED PERIOD. WHILE THERE IS POTENTIAL FOR DEEP
CONVECTION TO REDEVELOP OVER THE LOW-LEVEL CIRCULATION WITHIN THE
NEXT 48 HOURS AS THE UPPER-LEVEL TROUGH FILLS AND OUTFLOW IMPROVES,
IT IS UNLIKELY THAT THE SYSTEM WILL REINTENSIFY APPRECIABLY PRIOR
TO LANDFALL. DISSIPATION BELOW WARNING CRITERIA OVER MAINLAND JAPAN
IS ANTICIPATED, BUT A SMALL CHANCE REMAINS THAT BAROCLINIC
INFLUENCES FROM THE MID-LATITUDE FLOW PATTERN WILL ALLOW FOR
INTENSIFICATION AND TRANSITION TO A SUBTROPICAL OR EXTRATROPICAL
STRUCTURE NEAR THE END OF THE FORECAST PERIOD. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD GENERAL AGREEMENT
WITH THE OVERALL FORECAST SCENARIO, ALTHOUGH THE EXACT ORIENTATION
AND SPEED OF THE TURN AROUND THE STEERING RIDGE IS UNCERTAIN.
SEVERAL MEMBERS OF THE GEFS ENSEMBLE, AS WELL AS THE LATEST GFS
DETERMINISTIC MODEL RUN, STILL INDICATE THAT A MORE POLEWARD TRACK
INTO THE YELLOW SEA OR SEA OF JAPAN IS POSSIBLE. HOWEVER, THE
MAJORITY OF THE REMAINING NUMERICAL MODEL GUIDANCE IS TIGHTLY
PACKED AROUND BOTH THE CONSENSUS TRACK AND THE CURRENT JTWC
OFFICIAL TRACK FORECAST. CONSIDERING OVERALL SPREAD IN THE
GUIDANCE, TRACK FORECAST CONFIDENCE IS MEDIUM FOR BOTH THE
NEAR-TERM AND EXTENDED RANGE. THERE IS HIGH CONFIDENCE IN THE
INTENSITY FORECAST GIVEN NOTED CONSTRAINTS IN THE ENVIRONMENT,
WHICH WILL VERY LIKELY INDUCE CONTINUED GRADUAL WEAKENING
THROUGHOUT THE FORECAST PERIOD. NUMERICAL MODEL GUIDANCE IS IN GOOD
AGREEMENT WITH THE CURRENT INTENSITY FORECAST.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: HIGH
   INTENSITY 72-120 HR: HIGH//
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