Tropical Storm KONG-REY Advisory Thu Oct 04

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
RMKS/
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 30W (KONG-REY) WARNING NR 25//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 30W (KONG-REY), LOCATED APPROXIMATELY 247 NM SOUTH OF
KADENA AB, OKINAWA, JAPAN, HAS TRACKED NORTHWESTWARD AT 10 KNOTS OVER
THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
SHOWS THE SYSTEM WEAKENED AT A MORE RAPID RATE AS EVIDENCED BY
CENTRAL CONVECTIVE TOPS SIGNIFICANTLY WARMING UP AND FEEDER BANDS
UNRAVELING FAST AND BECOMING FRAGMENTED. THE INITIAL POSITION IS
PLACED WITH HIGH CONFIDENCE BASED ON A CLOUD-FILLED PINHOLE EYE IN
THE 040000Z 1-KM VISIBLE SATELLITE IMAGE. THE INITIAL INTENSITY OF 70
KNOTS IS BASED ON DVORAK ESTIMATES OF T4.0 TO 4.5 FROM PGTW, KNES,
AND RJTD AND REFLECTS THE RAPID WEAKENING. UPPER LEVEL ANALYSIS
INDICATES TY 30W IS STILL IN AN AREA OF LOW (05-10 KNOT) VERTICAL
WIND SHEAR (VWS) AND EXCELLENT DUAL OUTFLOW CHANNELS WITH A VERY
STRONG POLEWARD BIAS. ALONG TRACK SEA SURFACE TEMPERATURES (SSTS)
REMAIN WARM AT (28-29 CELSIUS). HOWEVER, THE CYCLONE IS TRACKING
ALONG A SWATH OF LOW OCEAN HEAT CONTENT. PLUS, COLD DRY AIR IS
ADVECTING FROM THE NORTHWEST AND BEGINNING TO WRAP INTO THE CENTER.
THESE SURFACE DYNAMICS ARE THE PRIMARY CAUSES FOR THE SIGNIFICANT
WEAKENING OF THE SYSTEM. THE CYCLONE IS TRACKING ALONG THE
SOUTHWESTERN PERIPHERY OF THE DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO
THE NORTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 30W WILL CONTINUE TO ROUND THE WESTERN EDGE OF THE STR AND
TURN MORE POLEWARD, CRESTING THE RIDGE AXIS NEAR TAU 24. AFTERWARD,
IT WILL RECURVE AND ACCELERATE NORTHEASTWARD AHEAD OF THE
MID-LATITUDE TROUGH APPROACHING FROM THE NORTHWEST. BY TAU 72, TY 30W
WILL BE IN THE SEA OF JAPAN (SOJ) JUST NORTHWEST OF MISAWA. NEAR TAU
36, THE SYSTEM WILL BEGIN EXTRA TROPICAL TRANSITION AND BY TAU 48
WILL BECOME A COLD-CORE LOW OVER THE COOLER WATERS OF THE KOREAN
STRAIT. INCREASING VWS AND DECREASING SSTS WILL CONTRIBUTE TO THE
WEAKENING TREND DOWN TO 45 KNOTS BY TAU 72.
   C. AFTER TAU 72, TY KONG-REY WILL CONTINUE TO ACCELERATE
NORTHEASTWARD AND BY TAU 96, WITH A TRACK SPEED EXCEEDING 30 KNOTS,
AND WILL HAVE CROSSED NORTHERN JAPAN EMERGING BACK IN THE PACIFIC
OCEAN EAST OF HOKKAIDO AS A GALE-FORCE 35-KNOT COLD CORE LOW, FULLY
EMBEDDED IN THE BAROCLINIC ZONE WITH AN EXPANSIVE WIND FIELD. DYNAMIC
MODEL GUIDANCE IS IN GOOD AGREEMENT WITH A SMALL ACROSS-TRACK SPREAD;
HOWEVER, THERE IS POOR AGREEMENT IN THE ALONG-TRACK FORECAST SPEEDS
AFTER TAU 36. THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC
FORECAST TRACK UP TO TAU 36, AND LOW CONFIDENCE AFTER TAU 36.
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