WDPN31 PGTW 022100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (AERE) WARNING NR 
010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 27.4N 127.5E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 56 NM NORTH-NORTHWEST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 11 KTS
   SIGNIFICANT WAVE HEIGHT: 17 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS WANING
CONVECTION OVER AN EXPOSED LOW-LEVEL CIRCULATION. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON AN EXPOSED
LOW-LEVEL CIRCULATION CENTER (LLCC) EVIDENT IN EIR IMAGERY AND 37
GHZ MICROWAVE IMAGERY FROM A 021647Z GMI PASS. THE INITIAL
INTENSITY OF 40 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON A
CONSENSUS OF SUBJECTIVE DVORAK INTENSITY ESTIMATES EQUIVALENT TO 35
KNOTS, A 021722Z AUTOMATED SATELLITE INTENSITY CONSENSUS ESTIMATE
OF 44 KNOTS AND A RECENT WIND SPEED OBSERVATION FROM YORONJIMA
ISLAND EXCEEDING 35 KNOTS. ANIMATED WATER VAPOR IMAGERY AND
ATMOSPHERIC MOTION VECTORS SHOW A CLOSED TROPICAL UPPER
TROPOSPHERIC TROUGH (TUTT) CELL DIRECTLY OVER THE LOW-LEVEL
CIRCULATION.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK AND PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.5 - 35 KTS
   KNES: T2.5 - 35 KTS
   CIMSS SATCON: 44 KTS AT 021722Z
   CIMSS ADT: 33 KTS AT 021740Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 30+ KTS
   SST: 28-29 CELSIUS
   OUTFLOW: WEAK POLEWARD
   OTHER FACTORS: TUTT CELL 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: TS 05W WILL CONTINUE TO TRACK POLEWARD FOR THE
NEXT 36 HOURS BEFORE TURNING EASTWARD TOWARD MAINLAND JAPAN AS IT
FOLLOWS THE FLOW ALONG THE WESTERN AND NORTHERN PERIPHERIES OF THE
CURRENT SUBTROPICAL STEERING RIDGE CURRENTLY SITUATED THE EAST. THE
ENVIRONMENT WILL REMAIN UNFAVORABLE FOR DEVELOPMENT IN THE NEAR TO
MEDIUM TERM AS THE TUTT CELL ANALYZED OVER THE LLCC PERSISTS,
INDUCING MODERATE TO STRONG VERTICAL WIND SHEAR AND UPPER-LEVEL
SUBSIDENCE NEAR THE LLCC. AS THE TUTT CELL FILLS, THE POTENTIAL FOR
INCREASED UPPER-LEVEL DIFFLUENCE AND CONVECTIVE DEVELOPMENT WILL
IMPROVE, BUT NOT ENOUGH TO OFFSET GENERALLY UNFAVORABLE
ENVIRONMENTAL CONDITIONS INCLUDING MARGINAL ALONG-TRACK SEA SURFACE
TEMPERATURES. IN THE EXTENDED RANGE, PASSAGE OVER LAND AN PERSISTENT
SHEAR ARE EXPECTED TO RESULT IN DISSIPATION. HOWEVER, THERE IS A
CHANCE THAT BAROLINIC INFLUENCES FROM THE MID-LATITUDE FLOW PATTERN
WILL ALLOW FOR INTENSIFICATION AND TRANSITION NEAR THE END OF THE
FORECAST PERIOD, BUT LIKELY NOT UNTIL AFTER THE SYSTEM HAS PASSED
MAINLAND JAPAN. 

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. A FEW
ENSEMBLE MEMBERS, PARTICULARLY IN THE GEFS ENSEMBLE, INDICATE A
MORE POLEWARD TRACK INTO THE YELLOW SEA OR SEA OF JAPAN. HOWEVER,
THAT SCENARIO APPEARS TO BE VERY UNLIKELY AT THIS POINT. THE
CURRENT JTWC TRACK FORECAST IS PLACED NEAR THE MULTI-MODEL
CONSENSUS, SLIGHTLY INSIDE THE PREVIOUS FORECAST TO ACCOUNT FOR A
TIGHTER TURN IN SOME DETERMINISTIC MODELS INCLUDING THE ECMWF
MODEL. THERE IS HIGH CONFIDENCE IN THE INTENSITY FORECAST GIVEN
NOTED CONSTRAINTS IN THE ENVIRONMENT THAT WILL LEAD TO GRADUAL
WEAKENING DURING 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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