WDPN32 PGTW 091500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (MUIFA) 
WARNING NR 013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.9N 128.0E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 396 NM SOUTH OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY INDICATES THAT
14W CONTINUES TO IMPROVE AND CONSOLIDATE ITS CENTRAL CONVECTION. IN 
THE PAST FEW HOURS, CONVECTIVE COVER HAS RADIALLY EXPANDED AND IS 
NOW THOROUGHLY OBSCURING THE LOW LEVEL CIRCULATION CENTER (LLCC). 
A 091005Z SSMIS 91GHZ MICROWAVE IMAGE REVEALS THAT WHILE OVERALL
CONVECTION HAS IMPROVED, THE SYSTEM HAS FAILED TO PRODUCE AN 
EYE AND CONSOLIDATE AROUND THAT FEATURE RESULTING IN LACK-LUSTER 
DVORAK NUMBERS. THE INITIAL POSITION IS PLACED WITH LOW CONFIDENCE 
BASED ON THE FULLY OBSCURED NATURE OF THE LLCC, AND POSITIONING 
PROVIDED BY FRUSTRATINGLY INFREQUENT MICROWAVE IMAGERY. THE INITIAL 
INTENSITY OF 60 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON PGTW 
AND KNES DVORAK INTENSITY ESTIMATES BOTH INDICATING 65 KTS, WHILE 
RJTD REMAINS CONSERVATIVE AT 50 KTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T3.0 - 45 KTS
   KNES: T4.0 - 65 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   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: TS 14W CONTINUES TO TRACK NORTHWESTWARD UNDER
THE STEERING INFLUENCE OF THE STR TO THE EAST. THE REPRESSIVE
TROPICAL UPPER TROPOSPHERE TROUGH (TUTT) THAT WAS SUPPRESSING
CONVECTION ON THE WESTERN SIDE OF 14W, HAS MOVED OFF TO THE WEST
ALLOWING THE SYSTEM TO GREATLY INCREASED ITS CONVECTIVE ENVELOPE
AND GET FRUSTRATINGLY CLOSE TO EYE DEVELOPMENT. OVER THE NEXT 12
HOURS THE SYSTEM WILL CONTINUE TO DEVELOP, EVENTUALLY REACHING
TYPHOON STRENGTH. AS THE SYSTEM CONTINUES TO INTENSIFY TO A
POSSIBLE PEAK OF 110 KTS BY TAU 48, THE STEERING FLOW SURROUNDING
THE SYSTEM BECOMES EERILY SIMILAR TO 12W AND WITH A SIMILARLY
NEGATIVE OUTCOME. A NEAR EQUATORIAL RIDGE (NER) WILL SET UP TO THE
SOUTH, A STR WILL BAR THE PATH TO THE NORTHEAST AND ANOTHER STR
WILL PREVENT ESCAPE TO THE NORTHWEST, AS THIS SETS UP, TRACK SPEEDS
WILL SLOW CONSIDERABLY THROUGH TAU 72. 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 ARE
IN THIS COLD POOL. THEREFOR, BY TAU 96, AS THE SYSTEM FINALLY
REGAINS NORTHWARD PROGRESSION THANKS TO A PASSING MID LATITUDE
TROUGH, 14W WILL BE ON A WEAKENING TREND. AS THE SYSTEM CONTINUES
INTO THE EAST CHINA SEA BY TAU 120, IT WILL HAVE LOST A SIGNIFICANT
PORTION OF ITS INTENSITY, BUT WILL LIKELY STILL BE A TYPHOON
STRENGTH TROPICAL CYCLONE.

MODEL DISCUSSION: NUMERICAL MODEL CROSS TRACK AGREEMENT REMAINS
GOOD THROUGH TAU 72, HOWEVER, AS DISCUSSED ABOVE THE COMPETING
STEERING ENVIRONMENT CREATES SIGNIFICANT ALONG TRACK DISCREPANCIES
AFTER TAU 48, AS VARIOUS MODELS TRY TO RESOLVE THE STEERING FLOW.
FOR THIS REASON, THE INITIAL JTWC FORECAST TRACK IS PLACED WITH
HIGH CONFIDENCE, AND THE EXTENDED TRACK FORECAST IS PLACED WITH LOW
CONFIDENCE. WITH THE EXCEPTION OF COAMPS-TC (GFS VERSION) RELIABLE
MODEL INTENSITY GUIDANCE IS IN FAIR AGREEMENT WITH ALL MEMBERS
SHOWING RAPID INTENSIFICATION (RI) THROUGH TAU 36 - TAU 48 AFTER
WHICH INTENSITIES STAGNATE AND EVENTUALLY FALL THROUGHOUT THE
REMAINING FORECAST PERIOD. COAMPS-TC (GFS VERSION) INITIALLY
FOLLOWS THE RI TREND BUT AFTER TAU 12, TAKES A DRAMATIC RAPID
WEAKENING TREND THROUGH TAU 36 AND THEN ANOTHER RI TREND THROUGH
THE FORECAST PERIOD. THE MAIN FACTOR INFLUENCING THE MODEL SPREAD
IS THE DURATION AND SOUTHWARD EXTENT THE SYSTEM IS QS OFF THE COAST
OF TAIWAN. FOR THESE REASONS 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//
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