WDPN31 PGTW 070300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 03W (GUCHOL) 
WARNING NR 005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.6N 134.1E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 797 NM SOUTH-SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 02 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A STEADILY,
ALBEIT SLOWLY, CONSOLIDATING SYSTEM WITH FRAGMENTED CONVECTIVE
BURSTS STRUGGLING TO MAINTAIN AND WRAP AROUND THE LOW LEVEL
CIRCULATION CENTER (LLCC). SIMILAR TO SIX HOURS AGO, DEEP
CONVECTIVE TOWERS CONTINUE TO FLARE UP AROUND THE LLCC BUT NONE
HAVE YET BEEN ABLE TO SUSTAIN THEMSELVES FOR MORE THAN AN HOUR TO
TWO. THUS, THE INNER CORE, WHILE IMPROVING, REMAINS SOMEWHAT
DISORGANIZED AND TRUE INTENSIFICATION HAS YET TO BEGIN. THE MOST
RECENT MICROWAVE IMAGE FROM 062009Z INDICATED A BROAD SWATH OF DEEP
CONVECTION LAYING IN A BAND ACROSS THE SOUTHERN HALF OF THE SYSTEM,
BUT LITTLE IN THE WAY OF ORGANIZED CONVECTIVE ACTIVITY IN THE
NORTHERN HEMISPHERE, DUE TO THE PRESENCE OF DRY AIR IN THE
MID-LEVELS TO THE NORTH. THE INITIAL POSITION IS ASSESSED WITH
MEDIUM CONFIDENCE AS THE PRECISE LLCC IS OBSCURED BUT ANALYSIS OF
THE OUTER BANDS PROVIDES SOME HINT AS TO THE CENTER. THE INITIAL
INTENSITY IS ALSO ASSESSED WITH MEDIUM CONFIDENCE, HEDGED SLIGHTLY
HIGHER THAN THE MULTI-AGENCY DVORAK CURRENT INTENSITY ESTIMATES IN
LIGHT OF AN ADT ESTIMATE OF 43 KNOTS AND THE GENERALLY IMPROVING
STRUCTURE. THE ENVIRONMENT REMAINS FAVORABLE, CHARACTERIZED BY LOW
VWS, WARM SSTS, HIGH OHC AND GOOD EASTWARD AND EQUATORWARD OUTFLOW
INTO A TUTT CELL LOCATED NEAR 19N 150E. THE SYSTEM HAS SLOWED DOWN
TO JUST TWO KNOTS AND TURNED MORE WESTWARD AS IT BUTTS UP AGAINST
AN EXTENSION OF THE SUBTROPICAL RIDGE (STR) THAT EXTENDS FROM
TAIWAN TO 30N 175E.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SOUTHERN SIDE OF A NARROW EXTENSION OF
THE STR TO THE NORTH. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.5 - 35 KTS
   KNES: T2.5 - 35 KTS
   CIMSS ADT: 43 KTS AT 062330Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 0-5 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE EASTWARD
   OTHER FACTORS: MODERATE EQUATORWARD OUTFLOW; DRY MID-LEVEL
AIRMASS TO THE NORTH

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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 03W HAS SLOWED DOWN AND TURNED A BIT
FURTHER TOWARDS THE WEST, AS THE NARROW RIDGE TO THE NORTH HAS
STRENGTHENED A BIT BASED ON THE LATEST SOUNDING FROM MINAMI DAITO
JIMA. BUT OTHER THAN THAT NEAR-TERM ADJUSTMENT, NO OTHER
SIGNIFICANT CHANGES TO THE STEERING PATTERN ARE EXPECTED AND THE
SYSTEM WILL TRACK SLOWLY TOWARDS THE WEST-NORTHWEST THROUGH THE
NEXT 36 TO 48 HOURS ALONG THE SOUTHERN SIDE OF THE RIDGE TO THE
NORTH. THE PASSAGE OF A STRONG SHORTWAVE TROUGH AND JET MAX OVER
JAPAN AROUND TAU 48 WILL BREAK THE RIDGE TO THE NORTH WHILE ALSO
BUILDING A NEW STR CENTER NEAR 30N 155E. THIS COMBINATION OF EVENTS
WILL ALLOW FOR TS 03W TO TURN NORTHWARD 72, THEN ACCELERATE
NORTHEASTWARD ALONG THE WESTERN SIDE OF THE BUILDING STR TO THE
EAST THROUGH THE REMAINDER OF THE FORECAST PERIOD. CONTINUED GOOD
ENVIRONMENTAL CONDITIONS; OUTFLOW INTO THE TUTT CELL TO THE EAST,
LOW VWS AND WARM SSTS, WILL FUEL RAPID INTENSIFICATION (RI) THROUGH
TAU 36, TO A PEAK OF 85 KNOTS, ASSUMING THE INNER CORE OF THE
SYSTEM CAN CONSOLIDATE QUICKLY. AFTER TAU 48, A REDUCTION IN
UPPER-LEVEL OUTFLOW, AND SOME INCREASED PRESSURE FROM A PUNCH OF
NORTHWESTERLY FLOW WILL LEAD TO A PERIOD OF STAGNANT INTENSITY
THROUGH TAU 72. THEREAFTER, OUTFLOW INTO THE BASE OF THE
UPPER-LEVEL TROUGH TO THE NORTH WILL OFFSET INCREASED VWS AND
DECREASING SSTS, ALLOWING FOR A VERY SLOW STEP-DOWN IN INTENSITY AS
THE SYSTEM ACCELERATES NORTHEASTWARD THROUGH THE REMAINDER OF THE
FORECAST. 

MODEL DISCUSSION: TRACK GUIDANCE REMAINS IN GOOD AGREEMENT ON THE
OVERALL RECURVE SCENARIO AND SPREAD IS A BIT LESS THAN IN THE
PREVIOUS RUN BUT AS IS NORMAL WITH A RECURVE SCENARIO, THERE
REMAINS A FAIR AMOUNT OF CROSS-TRACK SPREAD THROUGH THE TURN. THE
EUROPEAN MODELS CONTINUE TO SHOW A WIDER TURN, REACHING FURTHER TO
THE WEST, WHILE THE US MODELS LIE ON THE OPPOSITE SIDE OF THE
ENVELOPE. THE JTWC FORECAST STILL HEDGES TOWARDS THE US MODELS BUT
STILL LIES WEST OF THEIR TRACKERS. CONFIDENCE IS HIGH THROUGH THE
FIRST 48 HOURS, DECREASING TO MEDIUM THEREAFTER DUE TO THE
INCREASED SPREAD THROUGH AND AFTER THE TURN POLEWARD. INTENSITY
GUIDANCE HAS STARTED TO COME INTO BETTER AGREEMENT WITH ALL MEMBERS
OF THE CONSENSUS NOW AGREEING ON A FAIRLY RAPID INTENSIFICATION
TREND THROUGH TAU 48, FOLLOWED BY A SLOW WEAKENING TREND. SEVERAL
RI AIDS CONTINUE TO TRIGGER AND BRING THE CONSENSUS MEAN UP TO
ABOUT 80 KNOTS. THE JTWC FORECAST GOES A BIT HIGHER, TO 85 KNOTS,
IN LINE WITH THE BULK OF THE RI GUIDANCE, THEN RESUMES THE
CONSENSUS MEAN BY TAU 96. 

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