Tropical Storm LINGLING Advisory 9月6日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 15W (LINGLING) WARNING NR 16//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 15W (LINGLING), LOCATED APPROXIMATELY 141 NM WEST OF
KADENA AB, OKINAWA, JAPAN, HAS TRACKED NORTHWARD AT 11 KNOTS (KTS) OVER
THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE
IMAGERY SHOWS THE SYSTEM HAS MAINTAINED A SYMMETRIC SIGNATURE AND A
WELL-DEFINED 16-NM EYE AS IT SLIGHTLY DEEPENED WITH FEEDER BANDS
WRAPPING TIGHTER INTO THE EYE. THE INITIAL POSITION IS PLACED WITH
HIGH CONFIDENCE BASED ON A SHARPLY-OUTLINED CIRCULATION FEATURE IN A
COMPOSITE RADAR REFLECTIVITY LOOP FROM JMA THAT STACKED UP VERTICALLY
WITH THE EYE IN THE EIR ANIMATION. THE INITIAL INTENSITY OF 120KTS IS
BASED ON AN OVERALL ASSESSMENT OF AGENCY AND OBJECTIVE DVORAK
ESTIMATES RANGING FROM T6.0 TO T6.2 AND REFLECTS THE SLIGHT
INTENSIFICATION. UPPER LEVEL ANALYSIS INDICATES THAT THE SYSTEM IS IN
AN AREA OF LOW (05-10KT) RELATIVE VERTICAL WIND SHEAR, MITIGATED BY
THE STORM MOTION BEING IN-PHASE WITH UPPER LEVEL WIND FLOW.
ADDITIONALLY, POLEWARD OUTFLOW REMAINS ROBUST. ALONG-TRACK SEA
SURFACE TEMPERATURES (SST) AT 30C ARE ALSO CONDUCIVE. THE CYCLONE IS
TRACKING ALONG THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR)
TO THE EAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY LINGLING WILL CONTINUE ON ITS CURRENT TRACK, STEERED BY THE
STR. AFTER TAU 36, IT WILL TRACK MORE NORTH-NORTHEASTWARD AS IT
BEGINS TO ROUND THE STR AXIS, MAKE LANDFALL ALONG THE SOUTH COAST OF
NORTH KOREA NEAR HAEJU THEN DRAG OVER RUGGED TERRAIN AND CROSS INTO
NORTHEASTERN CHINA BY TAU 72. THE FAVORABLE CONDITIONS MENTIONED IN
PARA 2 WILL PROMOTE A LITTLE BIT MORE INTENSIFICATION TO A PEAK OF
125KTS BY TAU 12. AFTERWARD, INCREASING VWS AND COOLING SST IN THE
YELLOW SEA WILL GRADUALLY WEAKEN THE SYSTEM. AT TAU 36, TY 14W WILL
ENTER THE MIDLATITUDE BAROCLINIC ZONE AND BEGIN EXTRA-TROPICAL
TRANSITION (ETT) AND DECAY RAPIDLY AS IT TRACKS OVER RUGGED TERRAIN.
BY TAU 72, THE SYSTEM WILL COMPLETE ETT AND TRANSFORM INTO A STRONG
GALE-FORCE COLD CORE LOW. NUMERICAL MODELS ARE IN TIGHT AGREEMENT
THROUGHOUT THE FORECAST, WITH ONLY A SLIGHT INCREASE IN UNCERTAINTY
DUE TO DIFFERENCES IN ALONG-TRACK SPEED AFTER TAU 36. BASED ON THE
RELATIVELY LOW UNCERTAINTY, THERE IS HIGH CONFIDENCE IN THE JTWC
TRACK FORECAST WHICH CLOSELY FOLLOWS CONSENSUS.//
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