WDPN32 PGTW 081500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (MUIFA) 
WARNING NR 009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.3N 130.9E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 578 NM SOUTH-SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: WESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 19 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
GROWING SYSTEM OF DEEP CONVECTIVE PLUMES THAT ARE FULLY OBSCURING
THE LOW LEVEL CIRCULATION CENTER (LLCC). A 081008Z GMI 89GHZ COLOR
COMPOSITE MICROWAVE IMAGE SHOWS A WELL DEFINED CIRCULATION WITH A
SINGLE DEEP CONVECTIVE BAND WRAPPING INTO THE LLCC FROM THE
NORTHWESTERN SIDE OF THE CIRCULATION. THE 37GHZ IMAGE FROM THE SAME
GMI SERIES, REVEALS THAT AXISYMMETRIZATION HAS IN FACT TAKEN PLACE,
AND THE ULCC AND LLCC NOW VERTICALLY STACKED. THE INITIAL POSITION
IS PLACED WITH HIGH CONFIDENCE BASED ON EIR AND GMI IMAGERY. THE
INITIAL INTENSITY OF 45 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON AGENCY DVORAK ESTIMATES RANGING FROM 42-55 KNOTS WHILE
CIMMS ADT INDICATES A MORE CONSERVATIVE 35 KNOTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T2.5 - 35 KTS
   KNES: T3.5 - 55 KTS
   CIMSS ADT: 35 KTS AT 080810Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 0-5 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TS 14W IS CURRENTLY TRACKING GENERALLY
WESTWARD IN A FAVORABLE ENVIRONMENT CHARACTERIZED BY LOW VERTICAL
WIND SHEAR (0-5KTS), WARM SSTS (30-31C), AND GROWING DUAL CHANNEL
OUTFLOW ALOFT. OVER THE NEXT 12 HOURS, 14W IS FORECAST TO TURN
GENERALLY NORTHWESTWARD AS THE RIDGE TO THE EAST REORIENTS
VERTICALLY, AT THE SAME TIME THE SYSTEM WILL CONTINUE TO DEVELOP,
CONSOLIDATE AND INTENSIFY. BY TAU 24 THE SYSTEM IS FORECAST TO
REACH TYPHOON STRENGTH AND CONTINUE DEEPENING THROUGH TAU 48 BEFORE
REACHING ITS PEAK INTENSITY OF 110 KNOTS AND POSSIBLY HIGHER. DEEP
LAYERED STEERING FLOW FROM BOTH GFS AND ECMWF INCREASINGLY
INDICATION THAT THE NEW DOMINANT STEERING RIDGE THAT BUILDS INTO
THE NORTHEAST NEAR TAU 60 WILL NOT BE AS AFFECTED BY THE PASSING
SHORT WAVE TROUGH AS PREVIOUSLY FORECAST. THIS CHANGE TO THE STR
DYNAMICS WILL HAVE A POTENTIAL IMPACT ON THE EXTENDED TRACK
FORECAST BY WAY OF A MORE WESTERLY DRIFT TOWARDS TAIWAN OR A QS
PERIOD BEFORE THE RIDGE EVENTUALLY REORIENTS ALLOWING FOR NORTHWARD
PROGRESSION TO RESUME. THERE REMAINS A SIZABLE OHC COLD POOL EAST
OF TAIWAN THAT WILL CAUSE SIGNIFICANT WEAKENING AS THE SYSTEM
PASSES OVER IT. AS A RESULT DOWN TRACK INTENSITY WILL HAVE AN
INVERSE RELATIONSHIP TO THE DURATION OF TIME THE SYSTEMS IS IN THIS
COLD POOL. AFTER TURNING GENERALLY NORTH-NORTHWESTWARD PAST TAU 72
AND STARTING TO WEAKEN AS DISCUSSED, IF THE SYSTEM CAN ESCAPE THE
AFOREMENTIONED REGION RELATIVELY QUICKLY, 14W WILL ENTER THE EAST
CHINA SEA NEAR TAU 120, WEAKENED BUT STILL A TYPHOON STRENGTH
TROPICAL CYCLONE.

MODEL DISCUSSION: WITH THE EXCEPTION OF NAVGEM, NUMERICAL MODELS
REMAIN IN TIGHT AGREEMENT THROUGH TAU 48, AFTER WHICH AS MENTIONED
ABOVE VARIOUS MODELS ARE INDICATING A CHANGE TO THE STR DYNAMICS BY
WAY OF ALONG TRACK SPREADING. FOR EXAMPLE, ECMWF SHOWS AN EXTENSIVE
QS PERIOD AFTER TAU 48, WHILE GFS AND UKMET OFFER MORE CONSERVATIVE
OUTPUTS. ON THE OTHER END OF THE SPECTRUM, COAMPS-TC, NAVGEM AND
HWRF APPEAR UNFAZED BY THIS CHANGE IN THE LATER TAUS AND CONTINUE
THE SYSTEM WELL NORTH OF THE 26TH PARALLEL BY TAU 120. FOR THESE
REASONS THE INITIAL JTWC TRACK FORECAST IS PLACED WITH HIGH
CONFIDENCE, WHILE THE EXTENDED TRACK FORECAST IS PLACED WITH LOW
CONFIDENCE. RELIABLE MODEL INTENSITY GUIDANCE REMAINS IN FAIR
AGREEMENT WITH ALL MEMBERS SHOWING INTENSIFICATION THROUGH TAU 48
WITH A SIZABLE DISAGREEMENT ON THE PEAK INTENSITY. AFTER TAU 48 ALL
MODELS GENERALLY FLATTEN OUT AND EVENTUALLY TREND DOWNWARD THROUGH
THE FORECAST PERIOD. FOR THIS REASON THE JTWC INTENSITY FORECAST IS
PLACED WITH MEDIUM CONFIDENCE.

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