Tropical Storm MOLAVE Advisory 10月27日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 21W (MOLAVE) WARNING NR
012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 21W (MOLAVE), LOCATED APPROXIMATELY 472 NM EAST-
SOUTHEAST OF DA NANG, VIETNAM, HAS TRACKED WESTWARD AT 18 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY DEPICTS A STRENGTHENING SYSTEM WITH A  TRANSIENT
EYE THAT HAS BEGUN TO REFORM STARTING 1900Z. THE INITIAL POSITION
IS PLACED WITH HIGH CONFIDENCE BASED ON THE REFORMATION OF THE EYE
FEATURE IN THE EIR LOOP AND THE MICROWAVE EYE FEATURE PRESENT IN A
261830Z ATMS 16.5 GHZ IMAGE. THE INITIAL INTENSITY OF 90 KTS IS
ALSO PLACED WITH HIGH CONFIDENCE AND IS BASED ON A PGTW DVORAK
CURRENT INTENSITY ESTIMATE OF T5.0 (90 KTS). TY MOLAVE CONTINUES
TO TRACK UNDER THE STEERING INFLUENCE OF A SUBTROPICAL RIDGE (STR)
POSITIONED TO THE NORTH AND THROUGH AN ENVIRONMENT THAT IS
MARGINALLY FAVORABLE FOR FURTHER DEVELOPMENT WITH WARM (29-30
CELSIUS) SEA SURFACE TEMPERATURES (SST) AND WELL ESTABLISHED
EQUATORWARD AND WESTWARD OUTFLOW ALOFT OFFSET BY CONVERGENT UPPER
LEVEL FLOW ALONG THE NORTHERN PERIPHERY OF THE SYSTEM AND MODERATE
(20-25 KTS) VERTICAL WIND SHEAR (VWS).
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY MOLAVE IS FORECAST TO CONTINUE TRACKING WEST TO WEST-
NORTHWESTWARD THROUGH THE REMAINDER OF THE FORECAST PERIOD UNDER
THE STEERING INFLUENCE OF THE DEEP-LAYER STR OVER SOUTHERN CHINA.
THE SYSTEM IS EXPECTED TO CONTINUE TO INTENSIFY TO A PEAK OF 100
KNOTS IN THE NEXT 12 HOURS, LARGELY DUE TO FAVORABLE SSTS,
WEAKENING VWS (10-15 KTS BY TAU 12) AND IMPROVED UPPER LEVEL
OUTFLOW. AFTER TAU 12, THE ENVIRONMENT WILL BECOME LESS FAVORABLE
AS VWS INCREASES TO 20-25 KTS BY TAU 24, LEADING TO A SUSTAINED
INTENSITY OF 100 KTS BY TAU 24. BETWEEN TAU 24 AND TAU 36, COOLING
SSTS AND CONTINUED MARGINAL VWS WILL LEAD TO A GRADUAL WEAKENING
BEFORE LANDFALL AT TAU 36 SOUTH OF DA NANG, VIETNAM. BY THIS TIME,
TY MOLAVE WILL BEGIN TO DISSIPATE OVER LAND AND WEAKEN TO 65 KTS
DUE TO INTERACTION WITH THE UNDERLYING TERRAIN OF VIETNAM AND
INCREASING VWS. THE SYSTEM IS THEREAFTER FORECAST TO CONTINUE TO
DISSIPATE OVER LAND AS IT TRACKS THROUGH LAOS AND INTO THAILAND,
WHEREUPON IT WILL DISSIPATE OVER LAND BY TAU 72. NUMERICAL MODEL
TRACK GUIDANCE IS IN TIGHT AGREEMENT FOR THE ENTIRE 72 HOUR
FORECAST PERIOD WITH A MAXIMUM SPREAD IN MODEL TRACKS OF 140 NM BY
TAU 72. MODEL INTENSITY GUIDANCE CONTINUES TO DIVERGE IN THE NEAR
TERM WITH A WEAKENING TREND PREDICTED BY GFS DRIVEN GLOBAL AND
MESOSCALE MODELS, AND A GRADUAL INTENSIFICATION PREDICTED THROUGH
TAUS 12-24 BY COAMPS AND STATISTICAL-DYNAMICAL MODELS. OVERALL, THE
TIGHT AGREEMENT IN NUMERICAL MODEL GUIDANCE LENDS HIGH CONFIDENCE
IN THE JTWC FORECAST TRACK, WHICH IS PLACED ALONG THE JTWC MULTI-
MODEL CONSENSUS.//
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