Tropical Storm NAKRI Advisory 11月6日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 25W (NAKRI) WARNING
NR 01//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION 25W (NAKRI), LOCATED APPROXIMATELY 466 NM EAST-
SOUTHEAST OF DA NANG, VIETNAM, HAS TRACKED NORTHEASTWARD AT 04 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE
IMAGERY AND A 051408Z METOP-B ASCAT PASS DEPICT A CONSOLIDATING,
CLOSED LOW LEVEL CIRCULATION CENTER (LLCC) WITH CONVECTION AND 25-30
KT WINDS DISPLACED 50-90 NM FROM THE CENTER. THE INITIAL INTENSITY IS
SET AT 25 KTS BASED ON THE AFOREMENTIONED ASCAT PASS, WHICH SHOWED 30-
35 KTS TO THE NORTH IN THE ENVIRONMENTAL NORTHEASTERLY SURGE, BUT
MOSTLY 25 KT WINDS WRAPPED AROUND IN A BROAD SWATH TO THE SOUTH.
DVORAK CURRENT INTENSITY ESTIMATES RANGE FROM T1.0 (25 KTS) TO T2.0
(30 KTS) FROM KNES, PGTW, AND RJTD RESPECTIVELY. EXCELLENT POLEWARD
OUTFLOW TAPPING INTO THE MIDLATITUDE JET TO THE NORTH IS COMPETING
WITH HIGH (20-25 KT) VERTICAL WIND SHEAR (VWS) SURROUNDING THE SYSTEM
TO ENABLE SLOW CONSOLIDATION AND DEVELOPMENT. TD 25W HAS BEEN SLOWLY
MEANDERING EASTWARD IN THE SOUTH CHINA SEA IN A WEAK STEERING
ENVIRONMENT.
3. FORECAST REASONING.
   A. THIS IS THE INITIAL PROGNOSTIC REASONING MESSAGE ON THIS
SYSTEM AND SETS THE FORECAST PHILOSOPHY.
   B. TD 25W IS FORECAST TO DRIFT SLOWLY EASTWARD IN THE NEXT 48 HOURS
IN AN AMBIGUOUS STEERING ENVIRONMENT. IT WILL GRADUALLY INTENSIFY TO A
PEAK OF 60 KTS AT TAU 48 DUE TO THE ROBUST POLEWARD OUTFLOW AND WARM
(29 DEGREES CELSIUS) SEA SURFACE TEMPERATURES, WHICH WILL BE OFFSET BY
SUSTAINED MODERATE TO HIGH VWS, WHICH WILL LIMIT TOTAL INTENSIFICATION
POTENTIAL. THERE IS HIGH UNCERTAINTY IN THIS PORTION OF THE FORECAST
TRACK. NAVGEM AND THE UKMET ENSEMBLE TURN 25W TO THE NORTH IN THE NEAR
TERM, WHILE GFS, THE GFS ENSEMBLE, UKMET, AND ECMWF TURN 25W SLOWLY TO
THE SOUTH IN THE NEAR TERM, WITH GFS THE SOUTHERNMOST OUTLIER. ALL
MODELS THEN REFLECT A WESTWARD TURN AND ACCELERATION AFTER TAU 48 AS A
SUBTROPICAL RIDGE BUILDS IN TO THE WEST AND BECOMES THE DOMINANT
STEERING FEATURE. THE JTWC FORECAST TRACK FAVORS THE SOUTHERN SOLUTION
AND IS PLACED NEAR THE ECMWF SOLUTION AND THE MULTIMODEL CONSENSUS
WITH LOW CONFIDENCE.
C. AFTER TAU 72, ALL MODELS AGREE ON A WESTWARD TRACK TOWARDS VIETNAM.
TD 25W IS FORECAST TO MAKE LANDFALL AFTER TAU 96. IT WILL BEGIN A
GRADUAL WEAKENING TREND AFTER TAU 72 AS UPPER LEVEL DIVERGENCE
DECREASES, AND THEN WEAKEN MORE RAPIDLY DUE TO LAND INTERACTION AFTER
TAU 96. THERE IS HIGH CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST
TRACK.//
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