Tropical Storm NOUL Advisory 9月18日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 13W (NOUL) WARNING NR
010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 13W (NOUL), LOCATED APPROXIMATELY 105 NM EAST
OF DA NANG, VIETNAM, HAS TRACKED WEST-NORTHWESTWARD AT 13 KNOTS OVER
THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
DEPICTS A SLIGHT IMPROVEMENT IN CONVECTIVE BANDING OVER THE WESTERN
SEMICIRCLE WITH DEEP CONVECTION OBSCURING THE LOW-LEVEL CIRCULATION
CENTER (LLCC). A 171811Z ATMS 88.2GHZ MICROWAVE IMAGE INDICATES
CONVECTIVE BANDING OVER THE SOUTHERN SEMICIRCLE WITH SHALLOW BANDING
OVER THE NORTHERN SEMICIRCLE WRAPPING TIGHTLY INTO A DEFINED LLCC,
WHICH SUPPORTS THE INITIAL POSITION WITH GOOD CONFIDENCE. SURFACE
WINDS ALONG THE PERIPHERY OF THE SYSTEM HAVE INCREASED WITH HUE
(VVPB) SHOWING 23 KNOTS GUSTING TO 36 KNOTS WITH SLP NEAR 994MB AND
SANYA (59948) OVER SOUTHERN HAINAN ISLAND AT 30 KNOTS. BASED ON THE
SLIGHT IMPROVEMENT IN ORGANIZATION, THE INITIAL INTENSITY IS
INCREASED TO 50 KNOTS BASED ON KNES/PGTW DVORAK CURRENT INTENSITY
ESTIMATES OF 3.0-3.5 (45-55 KNOTS) AND ADT ESTIMATES RANGING FROM
3.0-3.2 (45-50 KNOTS). ENVIRONMENTAL ANALYSIS INDICATES PERSISTENT
NORTHEASTERLY VERTICAL WIND SHEAR (VWS) OF 25-30 KNOTS OFFSET BY
VIGOROUS EQUATORWARD OUTFLOW AND WARM SST VALUES (31C).
ADDITIONALLY, ANIMATED WATER VAPOR IMAGERY REVEALS IMPROVING
POLEWARD OUTFLOW. TS NOUL CONTINUES TO TRACK ALONG THE SOUTHERN
PERIPHERY OF THE SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTH.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS NOUL WILL TRACK GENERALLY WEST-NORTHWESTWARD TO WESTWARD
THROUGH THE FORECAST PERIOD UNDER THE STEERING INFLUENCE OF THE STR
ENTRENCHED TO THE NORTH. THE SYSTEM IS FORECAST TO INTENSIFY
SLIGHTLY TO 55 KNOTS PRIOR TO MAKING LANDFALL NEAR TAU 12, AND WILL
DISSIPATE AS IT TRACKS FURTHER INLAND OVER MOUNTAINOUS TERRAIN.
NUMERICAL MODEL GUIDANCE REMAINS IN GOOD AGREEMENT WITH A 55 NM
SPREAD IN SOLUTIONS AT TAU 12, LENDING HIGH CONFIDENCE IN THE JTWC
FORECAST TRACK.//
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