Tropical Storm SAOLA Advisory Fri Aug 31

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 10W (SAOLA) WARNING NR 16//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 10W (SAOLA), LOCATED APPROXIMATELY 195 NM SOUTHEAST OF
TAIPEI, TAIWAN, HAS TRACKED NORTH-NORTHWESTWARD AT 07 KNOTS OVER THE
PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY
SHOWS DEEP BANDING CONVECTION CONTINUES TO BUILD AROUND THE LOW
LEVEL CIRCULATION CENTER (LLCC) ALONG THE NORTHWESTERN QUADRANT.
TRACK SPEEDS HAVE BEEN SLOW BUT STEADY OVER THE PAST 12 HOURS. THE
CURRENT INTENSITY OF 75 KNOTS IS BASED ON DVORAK ESTIMATES FROM
PGTW, KNES AND RJTD. THE MAIN STEERING INFLUENCE APPEARS TO BE THE
NEAR EQUATORIAL RIDGE (NER) TO THE SOUTHEAST. IT APPEARS THE NER IS
SLOWLY BUILDING NORTHWESTWARD PUSHING TY 10W TOWARDS THE DEEP
LAYERED SUBTROPICAL RIDGE (STR) THAT EXTENDS OVER SOUTHERN JAPAN
INTO NORTHEASTERN CHINA. UPPER LEVEL ANALYSIS INDICATES THE
EQUATORWARD AND EASTWARD OUTFLOW CHANNELS REMAINS WELL ESTABLISHED,
HOWEVER RECENT ANIMATED WATER VAPOR IMAGERY INDICATES THE POLEWARD
OUTFLOW MIGHT BE STARTING TO IMPROVE AS AN INDUCED UPPER LEVEL
TROUGH MOVES INTO THE NORTHWESTERN QUADRANT BETWEEN TY 10W AND THE
PREVIOUSLY MENTIONED STR.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING.
   B. TY 10W IS FORECAST TO SLOWLY DRIFT IN A GENERAL NORTHWARD
DIRECTION UNDER THE INFLUENCE OF THE COMPETING STEERING MECHANISMS
OVER THE NEXT 24-36 HOURS. AFTER TAU 36 THE STR TO THE NORTH IS
EXPECTED TO BECOME THE DOMINANT STEERING INFLUENCE CAUSING THE TRACK
TO SHIFT TO THE NORTHWEST WITH A SUBSEQUENT SPEED INCREASE. UPPER-
LEVEL CONDITIONS SHOULD GRADUALLY BECOME MORE FAVORABLE AND SEA
SURFACE TEMPERATURES SHOULD PEAK NEAR 29C ALLOWING FOR TY 10W TO
INTENSIFY NEAR A PEAK OF 105 KNOTS BY TAU 48. LANDFALL IS EXPECTED
AROUND TAU 60, WITH FRICTIONAL FORCES STARTING TO WEAKEN TY 10W
THROUGH TAU 72.
   C. BEYOND TAU 72 TY 10W SHOULD RAPIDLY DISSIPATE OVER LAND.
NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT WITH EGRR REMAINING
THE EASTERN OUTLIER. THE FORECAST IS SLIGHTLY FASTER THAN THE
CONSENSUS THROUGH TAU 48 BUT SLOWS MORE QUICKLY ONCE TY 10W MAKES
LANDFALL. TRACK FORECAST CONFIDENCE REMAINS LOW DUE TO THE WEAK
STEERING ENVIRONMENT AND TIMING OF THE NORTHWESTWARD SHIFT.//
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