Tropical Storm AERE Advisory Fri Oct 07

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 22W (AERE) WARNING
NR 04//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 22W (AERE), LOCATED APPROXIMATELY 267 NM
EAST-SOUTHEAST OF HONG KONG, HAS TRACKED WESTWARD AT 15 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
(MSI) SHOWS BUILDING DEEP CONVECTION OVER A PREVIOUSLY FULLY EXPOSED
AND WELL DEFINED LOW LEVEL CIRCULATION CENTER (LLCC). A 060353Z GCOM
91GHZ MICROWAVE IMAGE SHOWS A SYMMETRIC, ORGANIZED LLCC WITH
CONVECTIVE BANDING WRAPPING INTO THE CENTER FROM THE NORTHERN SEMI-
CIRCLE. THE CURRENT POSITION IS PLACED WITH GOOD CONFIDENCE BASED ON
AN ASSESSMENT OF THE ABOVE IMAGERY COMBINED WITH RADAR IMAGERY FROM
TAIWAN. THE INTENSITY HAS BEEN INCREASED TO 30 KNOTS BASED ON THE
TIGHTLY WOUND LLCC AND IS SUPPORTED BY DVORAK INTENSITY ESTIMATES
RANGING FROM 25 TO 30 KNOTS. TD AERE IS LOCATED IN A MARGINALLY
FAVORABLE ENVIRONMENT WITH MODERATE VERTICAL WIND SHEAR (VWS) BUT
GOOD DIVERGENCE ALOFT, AIDED BY A POINT SOURCE TO THE EAST. SEA
SURFACE TEMPERATURES (SSTS) NEAR 30 CELSIUS ARE VERY FAVORABLE. TD
22W IS TRACKING WESTWARD UNDER THE INFLUENCE OF A LOW TO MID-LEVEL
SUB-TROPICAL RIDGE (STR) TO THE NORTH.
3. FORECAST REASONING.
   A. NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TD 22W WILL CONTINUE TO TRACK GENERALLY WESTWARD ALONG THE
SOUTHERN PERIPHERY OF THE STEERING STR OVER THE NEXT 24 HOURS. NEAR
TAU 24, THE CYCLONE WILL REACH A WEAK STEERING ENVIRONMENT BETWEEN
THE WESTERN EDGE OF THE STEERING STR AND ANOTHER BUILDING RIDGE OVER
CHINA. THIS WILL RESULT IN A QUASI-STATIONARY TRACK MOTION WITH A
SLIGHT TURN TO THE NORTH BEFORE THE SECOND RIDGE OVER CHINA ASSUMES
CONTROL AS THE DOMINANT STEERING MECHANISM. THIS WILL DRIVE THE
SYSTEM ON A SOUTHWESTWARD TRAJECTORY TOWARDS HAINAN. ENVIRONMENTAL
CONDITIONS WILL REMAIN MARGINALLY FAVORABLE WITH UPPER LEVEL OUTFLOW
IMPROVING THROUGH TAU 48, ALLOWING THE STORM TO REACH A PEAK
INTENSITY OF 50 KNOTS. AFTERWARDS, THE EASTERN EDGE OF THE BUILDING
RIDGE OVER CHINA WILL PRODUCE INCREASED VWS AND SUBSIDENCE ALOFT,
BEGINNING A WEAKENING TREND.
   C. IN THE EXTENDED FORECAST, THE STR BUILDING OVER CHINA WILL
CONTINUE TO PUSH TD 22W SOUTHWESTWARD. THE INCREASED VWS AND UPPER-
LEVEL SUBSIDENCE WILL HINDER FURTHER DEVELOPMENT AND LEAD TO A
GRADUAL DECAY. DYNAMIC MODEL GUIDANCE CONTINUES TO DEPICT A WIDE
SPREAD OF MODEL SOLUTIONS DUE TO THE COMPLICATED STEERING
ENVIRONMENT PAST TAU 12. THE JTWC FORECAST IS PLACED CLOSE TO THE
MULTI-MODEL CONSENSUS, HOWEVER, THERE HAS BEEN LITTLE TO NO
STABILITY IN THE MODEL GUIDANCE OVER THE FIRST FOUR CYCLES.
THEREFORE, THERE IS LOW CONFIDENCE IN THE JTWC TRACK FORECAST.//
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