Tropical Storm NAKRI Advisory 11月9日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 25W (NAKRI) WARNING NR 013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 25W (NAKRI), LOCATED APPROXIMATELY 347 NM WEST-
SOUTHWEST OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 11 KNOTS
(KTS) OVER THE PAST SIX HOURS. BASED ON CONVECTIVE BANDING WRAPPING
INTO THE LOW LEVEL CIRCULATION CENTER OBSERVED IN ANIMATED ENHANCED
INFRARED (EIR) SATELLITE IMAGERY, THE INITIAL POSITION IS SET WITH
GOOD CONFIDENCE. THE INITIAL INTENSITY REMAINS 65 KTS BASED ON MULTI-
AGENCY DVORAK CURRENT INTENSITY ESTIMATES OF T4.0 (65 KTS) FROM PGTW,
RJTD, RCTP, AND DEMS ALONG WITH A 081707Z SATCON ESTIMATE OF 58 KTS,
AND IS ABOVE A 081940Z ADVANCED DVORAK TECHNIQUE ESTIMATE OF 53 KTS.
THE SYSTEM IS TRANSITING THROUGH AN AREA OF STRONG (20-25 KTS)
VERTICAL WIND SHEAR (VWS), OFFSETTING THE UNIMPRESSIVE WESTWARD
DIFFLUENCE. HOWEVER, SEA SURFACE TEMPERATURES REMAIN FAVORABLE FOR
DEVELOPMENT AT 29 CELSIUS. TY 25W HAS ACCELERATED IN THE PAST SIX
HOURS, MOVING WESTWARD AT 11 KTS UNDER THE STEERING INFLUENCE OF A
SUBTROPICAL RIDGE (STR) TO THE NORTHWEST, THAT IS BUILDING EASTWARD
FROM MAINLAND SOUTHEAST ASIA.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE. WIND RADII HAVE BEEN
UPDATED BASED ON THE 081330Z METOP-A ASCAT PASS.
   B. THROUGHOUT THE FORECAST PERIOD, A STEERING RIDGE WILL CONTINUE
TO BUILD EASTWARD FROM MAINLAND SOUTHEAST ASIA. TY 25W WILL TRACK
ALONG THE SOUTHERN PERIPHERY OF THIS STR. TY 25W WILL MAINTAIN A
WESTWARD TRACK THROUGH TAU 36. AT THAT POINT, THE TRACK WILL SHIFT
WEST-NORTHWEST. THE INTENSITY WILL SLOWLY BEGIN TO WEAKEN AFTER TAU 12
AS VWS INCREASES. TY 25W HAS ALREADY LOST ITS PREVIOUSLY WELL DEFINED
POLEWARD OUTFLOW CHANNEL AS THE JET MOVED TO THE NORTHEAST, OUT OF THE
AREA. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT REGARDING THE
OVERALL TRACK FORECAST SCENARIO. HOWEVER, NAVGEM IS THE OUTLIER TO THE
NORTH. AFTER TAU 72, TRACK SPREAD BEGINS TO INCREASE, BUT THERE IS
SIGNIFICANT SPREAD, PARTICULAR WITH RESPECT TO TRACK SPEED, THROUGH
TAU 72. NOTABLY, HOWEVER, THE MULTI-MODEL CONSENSUS HAS REMAINED
FAIRLY CONSISTENT IN LOCATION FOR THE PAST TWO FORECAST CYCLES. THE
CURRENT JTWC FORECAST LIES WITHIN THE MAJORITY MODEL GROUPING NEAR THE
MULTI-MODEL CONSENSUS TRACK, WITH LOW CONFIDENCE GIVEN NOTED MODEL
SPREAD.
   C. TY 25W WILL DISSIPATE AS IT MOVES INLAND AFTER TAU 72. MODEL
GUIDANCE GENERALLY INDICATES PERSISTENT WESTWARD TO NORTHWESTWARD
MOTION OF THE WEAKENED LOW-LEVEL CENTER DURING THIS PERIOD.//
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