Tropical Storm SOUDELOR Advisory Thu Aug 06

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 13W (SOUDELOR) WARNING NR 30//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 13W (SOUDELOR), LOCATED APPROXIMATELY 324 NM SOUTH OF
KADENA AB, HAS TRACKED WESTWARD AT 10 KNOTS OVER THE PAST SIX HOURS.
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A 30NM
EYE WITH DECAYING DEEP CONVECTION OVER THE NORTHERN SEMI-CIRCLE AND
CURVED DEEP CONVECTIVE BANDING PERSISTING OVER THE SOUTHERN SEMI-
CIRCLE. THERE IS GOOD CONFIDENCE IN THE CURRENT POSITION BASED ON
THE EYE FEATURE. A 061240Z METOP-B IMAGE REVEALS CONCENTRIC EYEWALLS
WITH A SMALL INNER EYEWALL OF ABOUT 50NM DIAMETER AND A LARGER,
160NM DIAMETER EYEWALL, SEPARATED BY A WELL-DEFINED MOAT FEATURE.
THIS DOUBLE EYEWALL CONFIGURATION HAS PERSISTED FOR ABOUT 18 HOURS
WITH LITTLE CHANGE IN INTENSITY; THE CURRENT INTENSITY IS ASSESSED
AT 90 KNOTS BASED ON CURRENT INTENSITY ESTIMATES RANGING FROM 77 TO
102 KNOTS. UPPER-LEVEL ANALYSIS INDICATES A GENERALLY FAVORABLE
ENVIRONMENT WITH LOW VERTICAL WIND SHEAR AND RADIAL OUTFLOW;
HOWEVER, DRY AIR IS EVIDENT OVER THE NORTHWESTERN PERIPHERY OF THE
SYSTEM IN THE ISHIGAKI-JIMA SOUNDING AND RECENT TOTAL PRECIPITABLE
WATER IMAGERY. TY SOUDELOR IS TRACKING ALONG THE SOUTHERN PERIPHERY
OF A DEEP-LAYERED SUB-TROPICAL RIDGE (STR) TO THE NORTH.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 13W WILL CONTINUE ON A WEST-NORTHWESTWARD TRAJECTORY
THROUGH TAU 48 UNDER THE STEERING INFLUENCE OF THE DOMINANT STR. IN
THE SHORT TERM, TY 13W IS FORECAST TO RE-INTENSIFY AFTER THE SYSTEM
COMPLETES THE CURRENT EYEWALL REPLACEMENT CYCLE (ERC); HOWEVER,
THERE IS A GREAT DEAL OF UNCERTAINTY IN TIMING AN ERC AS THEY CAN
PERSIST FOR 2 TO 3 DAYS. THIS UNCERTAINTY IS REFLECTED IN THE
INTENSITY GUIDANCE, WHICH VARIES SIGNIFICANTLY IN THE DEGREE OF RE-
INTENSIFICATION THROUGH TAU 36. THE JTWC FORECAST CONTINUES TO
REFLECT A RE-INTENSIFICATION TO 105 KNOTS BY TAU 24 DUE TO
ENHANCED POLEWARD OUTFLOW, INCREASING SST AND INCREASING OCEAN HEAT
CONTENT. NEAR TAU 36, TY 13W IS FORECAST TO MAKE LANDFALL OVER
TAIWAN THEN WEAKEN RAPIDLY AS IT TRANSITS ACROSS THE MOUNTAINOUS
TERRAIN THEN RE-EMERGE OVER THE TAIWAN STRAIT AS A WEAK TYPHOON. BY
TAU 48, TY SOUDELOR WILL MAKE A SECOND LANDFALL OVER THE EASTERN
COAST OF CHINA NEAR QUANZHOU.
   C. IN THE EXTENDED TAUS, TY SOUDELOR WILL APPROACH THE WESTERN
EXTENT OF THE STEERING STR AND TURN POLEWARD. THE CYCLONE WILL
CONTINUE TO DETERIORATE AS IT TRACKS INLAND, LEADING TO ITS
DISSIPATION OVER LAND BY THE END OF THE FORECAST PERIOD. DYNAMIC
MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT THROUGHOUT THE FORECAST
PERIOD, LENDING HIGH CONFIDENCE IN THE JTWC TRACK FORECAST.//
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