Tropical Storm MEGI Advisory сб, 24.09.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 20W (MEGI) WARNING
NR 04//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A BROAD
SYSTEM WITH IMPROVED FORMATIVE BANDING AND COOLING CLOUD TOPS
ASSOCIATED WITH DEEP FLARING CENTRAL CONVECTION OVER THE LAST SIX
HOURS. THE INITIAL POSITION IS PLACED WITH POOR CONFIDENCE AND IS
BASED ON A 231550Z AMSR2 IMAGE AND A 231218Z AMSU 89 GHZ IMAGE, BOTH
SHOWING THE APPROXIMATE LOW LEVEL CIRCULATION CENTER WITH THE
POSSIBILITY OF MULTIPLE VORTICES EXISTING AT THE SURFACE. THE
INITIAL INTENSITY IS ASSESSED AT 35 KNOTS AND IS BASED ON THE LOWER
END OF AGENCY DVORAK ESTIMATES RANGING FROM T2.5 TO T3.0 (35 TO 45
KNOTS). HIGHER DVORAK ESTIMATES ARE ATTRIBUTED TO IMPROVED
CONVECTIVE ACTIVITY RELATED TO DIURNAL CHANGES, HOWEVER THE
CIRCULATION REMAINS BROAD AND THE CONVECTIVE SIGNATURE OBSERVED IN
THE AFOREMENTIONED MICROWAVE IMAGES DOES NOT WARRANT AN INTENSITY
INCREASE AT THIS TIME. UPPER-LEVEL ANALYSIS INDICATES A FAVORABLE
ENVIRONMENT WITH A WELL-ESTABLISHED EQUATORWARD OUTFLOW CHANNEL AND
A POLEWARD CHANNEL STARTING TO IMPROVE. VERTICAL WIND SHEAR IS LOW
(5 TO 10 KNOTS) AND SSTS ARE FAVORABLE, NEAR 30 CELSIUS. CURRENTLY
TS MEGI IS TRACKING NORTHWESTWARD ALONG THE PERIPHERY OF A MID TO
LOW LEVEL SUBTROPICAL RIDGE POSITIONED TO THE NORTHEAST.
3. FORECAST REASONING.
    A. THERE IS NO CHANGE TO FORECAST PHILOSOPHY FROM THE PREVIOUS
PROGNOSTIC REASONING BULLETIN.
    B. TS MEGI WILL CONTINUE TO TRACK NORTHWESTWARD THROUGHOUT THE
FORECAST PERIOD AS THE STEERING RIDGE BUILDS AND EXTENDS WESTWARD.
STEADY INTENSIFICATION IS EXPECTED THROUGH TAU 72 AS TS MEGI
CONTINUES TO CONSOLIDATE WITHIN A VERY FAVORABLE ENVIRONMENT
REACHING A PEAK INTENSITY OF 80 KNOTS.
    C. IN THE EXTENDED PERIOD, BEYOND TAU 72 TS MEGI IS EXPECTED TO
CONTINUE ITS NORTHWESTERN TRACK MAKING LANDFALL OVER THE SOUTHERN
PORTION OF TAIWAN WEAKENING RAPIDLY INTO A TROPICAL STORM. THIS
TRACK WILL CONTINUE INTO CHINA BEFORE DISSIPATING NEAR TAU 120.
DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGHOUT THE FORECAST
PERIOD WITH THE EXCEPTION OF GFDN DEPARTING FROM THE GROUP CLUSTER
SHOWING A TRACK SIGNIFICANTLY SOUTH. THE FORECAST TRACK IS PLACED
WITH GOOD CONFIDENCE LOCATED CLOSE TO THE MULTI-MODEL CONSENSUS.//
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