Tropical Storm SOUDELOR Advisory Mon Aug 31

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 13W (SOUDELOR) WARNING
NR 07//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 13W (SOUDELOR), LOCATED APPROXIMATELY 540 NM
EAST OF SAIPAN, HAS TRACKED WESTWARD AT 10 KNOTS OVER THE PAST SIX
HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS AN
INCREASING MOISTURE FIELD WITH IMPROVED ORGANIZATION IN THE
CONVECTION ASSOCIATED WITH A CONSOLIDATING LOW LEVEL CIRCULATION
CENTER (LLCC). THE WATER VAPOR LOOP SHOWS POLEWARD MOVEMENT AND SOME
WEAKENING TO THE TUTT CELL LOCATED NORTH OF THE CYCLONE, ALLOWING
THE INCREASED ORGANIZATION. A 311632Z SSMI 37GHZ MICROWAVE IMAGE
SHOWS INCREASED DEFINITION TO THE LLCC WITH THE MOST SIGNIFICANT
CONVECTION ALONG THE NORTHEASTERN QUADRANT. THE CURRENT POSITION IS
BASED ON THE LLCC IDENTIFIED IN THE AFOREMENTIONED IMAGERY AND
SUPPORTED BY SATELLITE FIXES FROM PGTW AND RJTD. THE INITIAL
INTENSITY IS HELD AT 35 KNOTS BASED ON AN ASSESSMENT OF DVORAK
INTENSITY ESTIMATES FROM ALL AGENCIES AND SUPPORTED BY AN ASCAT PASS
FROM 311121Z SHOWING 35 KNOT WINDS ALONG THE NORTHERN PERIPHERY. THE
UPPER LEVEL ENVIRONMENT IS IMPROVING WITH THE DECREASED EFFECTS OF
THE TUTT CELL ALLOWING INCREASED RADIAL OUTFLOW AND DECREASED WIND
SHEAR. TS SOUDELOR IS CURRENTLY 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. TS 13W IS FORECAST TO TRACK GENERALLY TO THE WEST-NORTHWEST
THROUGHOUT THE FORECAST PERIOD UNDER THE STEERING INFLUENCE OF THE
STR. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO CONTINUE TO IMPROVE
OVER THE NEXT 12 HOURS WHICH, IN ADDITION TO ALONG-TRACK SEA SURFACE
TEMPERATURES (SSTS) ABOVE 30 CELSIUS, WILL SUPPORT A PERIOD OF RAPID
INTENSIFICATION AFTER TAU 12. THIS INTENSIFICATION TREND WILL
CONTINUE THROUGH TAU 72 AS ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE.
   C. IN THE EXTENDED FORECAST, INTENSIFICATION WILL BE TEMPERED BY
A DECREASE IN SSTS AND OCEAN HEAT CONTENT AS WELL AS A SLIGHT
INCREASE IN VWS. DYNAMIC MODEL GUIDANCE IS IN DECENT AGREEMENT
THROUGH TAU 48, WITH A 130NM SPREAD AS THE CYCLONE PASSES THROUGH
THE MARIANAS ISLAND CHAIN. AFTER TAU 48, THE SPREAD INCREASES DUE TO
THE MODEL'S DEPICTION IN THE EXTENT OF THE STEERING RIDGE. NAVGEM,
COAMPS-TC AND GFDN TRACK THE SYSTEM ON A NORTHWESTWARD TRAJECTORY AS
THEY DEPICT THE STR WEAKER AND SITUATED FURTHER EAST. GFS, HWRF, AND
ECMF KEEP TS SOUDELOR ON A FLATTER TRACK WITH THE STR MORE
PRONOUNCED AND SET UP FURTHER WEST. THE JTWC TRACK IS POSITIONED
JUST SOUTH OF THE MULTI-MODEL CONSENSUS, CLOSER TO THE GFS AND
EUROPEAN MODELS BASED ON THEIR INITIALIZATION OF THE STR. DUE TO THE
INCREASING MODEL SPREAD BEYOND TAU 48, THERE IS LOW CONFIDENCE IN
THE JTWC TRACK FORECAST.//
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