Tropical Storm HALONG Advisory 11月4日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 24W (HALONG) WARNING NR 006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 24W (HALONG), LOCATED APPROXIMATELY 453 NM EAST-
NORTHEAST OF SAIPAN, CNMI, HAS TRACKED NORTHWESTWARD AT 10 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY SHOWS THE SYSTEM CONTINUED TO DEEPEN AS IT DEVELOPED A 10-NM
RAGGED AND OBSCURED OBLONG EYE. THE INITIAL POSITION IS PLACED WITH
GOOD CONFIDENCE BASED ON THE EYE FEATURE, SLIGHTLY ADJUSTED FOR
TILT. THE INITIAL INTENSITY OF 65KTS IS BASED ON THE PGTW DVORAK
INTENSITY ESTIMATE OF T4.0/65KTS. ENVIRONMENTAL ANALYSIS REVEALS
FAVORABLE CONDITIONS WITH NEAR-RADIAL OUTFLOW, LOW (<15KTS) VERTICAL
WIND SHEAR (VWS), WARM SST (29-30C) AND FAVORABLE OCEAN HEAT CONTENT
VALUES. TY 24W IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A
DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE NORTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 24W WILL CONTINUE ON ITS CURRENT TRACK THROUGH TAU 36.
AFTERWARD, IT WILL ROUND THE STR AXIS AND TURN NORTHWARD THEN
ACCELERATE NORTHEASTWARD ON THE POLEWARD SIDE OF THE STR AND BEGIN
EXTRA-TROPICAL TRANSITION (ETT) AS IT INTERACTS WITH THE MIDLATITUDE
WESTERLIES. THE SYSTEM WILL INTENSIFY UNDER FAVORABLE CONDITIONS TO
A PEAK OF 105 KNOTS BY TAU 48 DUE TO IMPROVED POLEWARD OUTFLOW INTO
THE MIDLATITUDE WESTERLIES. THE NUMERICAL MODELS ARE IN FAIR
AGREEMENT WITH THE TRACK AND TIMING OF THE RECURVE LENDING HIGH
CONFIDENCE TO THIS PORTION OF THE JTWC TRACK FORECAST.
   C. IN THE EXTENDED PERIOD, TY HALONG WILL CONTINUE TO ACCELERATE
NORTHEASTWARD AS IT TRACKS WITHIN THE MIDLATITUDE WESTERLIES AND
SHOULD COMPLETE ETT BY TAU 120. THE SYSTEM IS FORECAST TO SLOW AFTER
TAU 96 AS IT ENCOUNTERS A STRONG, LOW-LEVEL MIDLATITUDE HIGH, WHICH
MAY TURN THE SYSTEM MORE POLEWARD. TY 24W WILL WEAKEN RAPIDLY DUE TO
INCREASING VWS AND COOLER SST, HOWEVER, THE SYSTEM WILL STILL BE A
GALE FORCE COLD-CORE LOW AT TAU 120 WITH AN EXPANSIVE WIND FIELD.
NUMERICAL MODELS DIVERGE SIGNIFICANTLY AFTER TAU 72, LENDING LOW
CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC TRACK FORECAST.//
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