WDPN32 PGTW 251500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (SAOLA) WARNING NR 008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.4N 123.8E
   INITIAL INTENSITY: 90 KTS
   GEOGRAPHIC REFERENCE: 480 NM SOUTH-SOUTHWEST OF KADENA AB
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A LARGE
CENTRAL DENSE OVERCAST (CDO), FULLY OBSCURING THE LOW LEVEL
CIRCULATION CENTER (LLCC) BENEATH. A MUCH NEEDED 250953Z RCM-2
SYNTHETIC APERTURE RADAR (SAR) PASS REVEALED A SIGNIFICANTLY
IMPROVED CIRCULATION, BOTH IN SIZE AND INTENSITY OF THE WIND FIELD
IN EVERY QUADRANT. THERE IS A BAND OF 86-90KT WINDS THAT NEARLY
ENCIRCLES THE CORE OF THE SYSTEM WITH TWO SMALL PATCHES OF 95-100KT
WINDS IN THE EASTERN AND NORTHERN QUADRANTS. A 251013Z SSMIS 91GHZ
MICROWAVE IMAGE REVEALS A ROBUST MICROWAVE EYE WITH DEEP CONVECTION
STILL STRUGGLING TO WRAP THE NORTHWESTERN QUADRANT OF THE
CIRCULATION. AS CLOUD TOP TEMPERATURES HAVE CONTINUED TO COOL, NOW
ANALYZED AT -82C, DVORAK INTENSITY ESTIMATES HAVE CLIMBED TO
T4.5-5.0 THOUGH BASED ON THE RECENT SAR PASS, AN EYE WILL BE NEEDED
BEFORE DVORAK ESTIMATES REJOIN THE SYSTEMS RAPID INTENSIFICATION.
THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON EIR,
SAR AND SSMIS DATA. THE INITIAL INTENSITY OF 90 KTS IS ASSESSED
WITH MEDIUM CONFIDENCE BASED ON THE RECENT SAR PASS INTENSITY
GREATLY DIVERGING FROM ALL OTHER INTENSITY ESTIMATES.

INITIAL WIND RADII BASIS: SAR DATA 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE WEST,
CENTERED NEAR HONG KONG. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T4.0 - 65 KTS
   RCTP: T4.0 - 65 KTS
   KNES: T5.0 - 90 KTS
   CIMSS SATCON: 64 KTS AT 251111Z
   CIMSS ADT: 77 KTS AT 251130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE RADIAL
   OTHER FACTORS: ONGOING RAPID INTENSIFICATION (RI)

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: BASED ON THE RECENT 250953Z RCM-2 SAR
PASS, 09W IS MUCH STRONGER THAN PREVIOUSLY FORECAST AND IS STILL 
UNDERGOING RI. 

FORECAST DISCUSSION: CURRENT UNDERGOING RAPID INTENSIFICATION (RI),
TYPHOON 09W (SAOLA) IS FORECAST TO INCREASE EQUATORWARD TRACK SPEED
OVER THE COMING HOURS, UNDER THE STEERING INFLUENCE OF THE STR TO
THE WEST. OVER THE NEXT 36 HOURS, 09W WILL PROCEED GENERALLY
EQUATORWARD UNTIL ITS FORWARD PROGRESS IS HALTED BY A NEAR
EQUATORIAL RIDGE (NER) TO THE SYSTEMS SOUTH. BY TAU 48, 09W WILL
EXECUTE A GRACEFUL EASTWARD AND EVENTUALLY NORTHWARD COURSE CHANGE.
POTENTIAL INTERACTION WITH A VERY LARGE TROPICAL CYCLONE NORTH OF
GUAM, IF IT ACTUALLY DEVELOPS, WILL HAVE A SIZEABLE IMPACT ON THE
EXACT EXTENDED TRACK FORECAST OF 09W. IF THE NEW SYSTEM DOES
DEVELOP, THEN THE TRACK WILL LIKELY PUSH THROUGH THE LUZON STRAIT.
IF IT DOES NOT DEVELOP OR IS WEAKER THAN SEVERAL DETERMINISTIC
MODELS INDICATE, THIS WOULD LEAD TO A TRACK FURTHER TOWARDS THE
NORTH. IN TERMS OF INTENSITY, 09W IS FORECAST TO QUICKLY INTENSIFY
TO 115KTS BY TAU 36, AS THE SYSTEM EXECUTES THE HAIRPIN NORTHWARD
TURN, THERE IS POTENTIAL FOR COOLER WATER TO BE UPWELLED BENEATH
THE SYSTEM, RESULTING IN A SOMEWHAT FLATTENED INTENSITY TREND. THIS
STAGNATION HOWEVER, IS QUICKLY RESOLVED AS POLEWARD TRACK MOVEMENT
IS ONCE AGAIN ACHIEVED. THE SYSTEM IS FORECAST TO REACH A PEAK
INTENSITY AT THE END OF THE CURRENT FORECAST PERIOD IN THE
NEIGHBORHOOD OF 130KTS AND POSSIBLY HIGHER.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT WITH ALL
MEMBERS GENERALLY FOLLOWING THE JTWC FORECAST TRACK THOUGH TAU 72.
AFTER TAU 72 HOWEVER, CROSS TRACK SPREADING INCREASES AS VARIOUS
MEMBERS ATTEMPT TO ACCOUNT FOR THE AFOREMENTIONED POTENTIAL VERY
LARGE TROPICAL CYCLONE THAT MAY FORM IN THE PHILIPPINE SEA. FOR
THESE REASONS THE JTWC TRACK FORECAST IS PLACED INITIALLY WITH
MEDIUM CONFIDENCE AND WITH LOW CONFIDENCE THERE AFTER. RELIABLE
MODEL INTENSITY GUIDANCE IS IN FAIR AGREEMENT WITH ALL MEMBERS
REFLECTING A SHARP INTENSIFICATION TREND THROUGH TAU 24 WITH A MORE
GRADUAL INCREASE THROUGH TAU 48. AFTER TAU 48, GENERAL STAGNATION
AND EVENTUALLY RENEWED INTENSIFICATION THROUGH THE FORECAST PERIOD.
WHILE THE JTWC INTENSITY TREND IS ECHOED BY A VAST MAJORITY OF THE
MEMBERS, THERE IS A ROUGHLY 30-40KT SPREAD IN THE GUIDANCE BY TAU
120. FOR THESE REASON THE JTWC INTENSITY FORECAST IS PLACED WITH
OVERALL MEDIUM CONFIDENCE.  

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