WDPN31 PGTW 080300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 03W (GUCHOL) WARNING NR 009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.9N 131.8E
   INITIAL INTENSITY: 65 KTS
   GEOGRAPHIC REFERENCE: 498 NM NORTH-NORTHWEST OF KAYANGEL
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 27 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A LARGE
CLUSTER OF PERSISTENT DEEP CONVECTION OVER THE EASTERN SEMICIRCLE
WITH SPIRAL CONVECTIVE BANDS WRAPPING INTO THE LOW LEVEL
CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH MEDIUM 
CONFIDENCE BASED ON AGENCY POSITION FIXES ALONG WITH THE MSI WHICH 
SHOWS A BANDING EYE FEATURE. A 072210Z SSMIS 91GHZ IMAGE SHOWED A 
MICROWAVE EYE FEATURE, WITH STRONG CONVECTIVE BANDS WRAPPING ON THE 
EASTERN PERIPHERY OF THE LLCC. THE INITIAL INTENSITY IS ASSESSED AT 
65 KTS BASED ON A COMBINATION OF OBJECTIVE AND SUBJECTIVE DVORAK 
INTENSITY ESTIMATES RANGING FROM T3.0 (45 KTS) TO T4.5 (77 KTS). 
ADDITIONALLY, AN EARLIER 072105Z SMAP WINDSPEED IMAGE SHOWS A BROAD 
SWATH OF 60-65 KNOTS ON THE NORTHERN SEMICIRCLE. ENVIRONMENTAL 
CONDITIONS REMAIN FAVORABLE WITH MODERATE EASTWARD OUTFLOW AND LOW 
VERTICAL WIND SHEAR (VWS) AS WELL AS WARM SEA SURFACE TEMPERATURES 
(SSTS) AND HIGH OCEAN HEAT CONTENT (OHC).

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: AN EXTENSION OF THE SUBTROPICAL RIDGE
(STR) TO THE NORTHEAST AND A NEAR-EQUATORIAL RIDGE (NER) TO THE
SOUTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T3.0 - 45 KTS
   KNES: T4.0 - 65 KTS
   CIMSS ADT: 59 KTS AT 072030Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE EASTWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: OVERALL, OVER THE PAST SIX HOURS TYPHOON 03W
HAS REMAINED ON A STEADY WEST-NORTHWESTWARD TRACK ALONG THE
SOUTHWESTERN PERIPHERIES OF THE SUBTROPICAL RIDGE (STR) TO THE 
NORTHEAST AND A NEAR-EQUATORIAL RIDGE (NER) TO THE SOUTH. AFTER TAU 
24, TY 03W IS EXPECTED TO TURN AND TRACK NORTH-NORTHWESTWARD, AS A 
MAJOR SHORTWAVE TROUGH MOVING OVER JAPAN WILL CREATE A BREAK IN THE 
STR TO THE NORTH. ADDITIONALLY, THE STR NEAR 30N 160E IS EXPECTED TO 
AMPLIFY. AS A RESULT, THE SYSTEM WILL RAPIDLY TURN POLEWARD AND 
ACCELERATE NORTHEASTWARD ALONG THE WESTERN PERIPHERY OF THE STR 
THROUGHOUT THE FORECAST. IN TERMS OF INTENSITY, 03W WILL CONTINUE TO 
RAPIDLY INTENSIFY OVER THE NEXT 36 HOURS, UNDER FAVORABLE CONDITIONS 
CHARACTERIZED BY ROBUST OUTFLOW, LOW VWS, WARM SSTS. THIS WILL ALLOW 
THE SYSTEM TO REACH A PEAK INTENSITY OF NEAR 90 KNOTS AT TAU 24. 
AFTER TAU 24, A COMBINATION OF COOLER SSTS, INCREASING NORTHWESTERLY 
VWS, AND CONSTRICTED OUTFLOW ALOFT, WILL COMBINED TO SLOWLY WEAKEN 
THE SYSTEM. BY TAU 120, THE SYSTEM IS EXPECTED TO BEGIN SUBTROPICAL
TRANSITION.

MODEL DISCUSSION: NUMERICAL TRACK GUIDANCE REMAINS IN GOOD
AGREEMENT ON THE OVERALL RECURVE SCENARIO BUT CONTINUES TO SHOW
LARGE CROSS TRACK SPREAD IN THE LATER TAUS. THE JTWC TRACK FORECAST
IS CLOSE TO THE MULTI-MODEL CONSENSUS THROUGH 48 HOURS WITH HIGH
CONFIDENCE AS THERE IS ONLY A 73 NM SPREAD IN MANY OF THE CONSENSUS
MEMBERS. AFTER TAU 48, MODEL SPREAD INCREASES WITH GFS AND NAVGEM
MAKING UP THE EASTERN EDGE OF THE ENVELOPE, WHILE JGSM AND UEM2
MAKE UP THE WESTERN OUTLIER. BEYOND TAU 48, CONFIDENCE REMAINS
MEDIUM DUE TO THE LARGE SPREAD IN TRACK GUIDANCE. THE JTWC INTENSITY 
FORECAST IS PLACED SLIGHTLY ABOVE CONSENSUS THROUGH TAU 48 DUE TO THE 
EXPECTED INTENSIFICATION TREND AND MULTIPLE RAPID INTENSIFICATION 
(RI) AIDS BEING TRIGGERED. THE INTENSITY FORECAST LIES NEAR CONSENSUS 
THROUGH THE REMAINDER OF THE FORECAST WITH MEDIUM CONFIDENCE.

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