Tropical Storm KONG-REY Advisory Thu Oct 04

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 30W (KONG-REY) WARNING NR 22//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 30W (KONG-REY), LOCATED APPROXIMATELY 351 NM
SOUTH-SOUTHEAST OF KADENA AB, OKINAWA, JAPAN, HAS TRACKED
NORTHWESTWARD AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY SHOWS THAT DEEP CONVECTION HAS
CONTINUED TO WEAKEN, SPECIFICALLY IN THE NORTHWEST QUADRANT. THE EYE
FEATURE REMAINS BUT IT HAS BECOME LESS DEFINED OVER THE PAST SEVERAL
HOURS. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A
030600Z HIMAWARI VISIBLE SATELLITE IMAGE WHICH SHOWS THE ERODING, NOW
7 NM WIDE EYE. THE INITIAL INTENSITY OF 105 KNOTS IS HEDGED SLIGHTLY
ABOVE DVORAK CURRENT INTENSITY (CI) ESTIMATES OF T5.5 (102 KNOTS)
FROM RJTD AND PGTW AND SLIGHTLY BELOW A 030454Z SATCON ESTIMATE OF
112 KNOTS. ENVIRONMENTAL ANALYSIS SHOWS THAT TY 30W IS EXPERIENCING
FAVORABLE VERTICAL WIND SHEAR (5 TO 10 KNOTS) AND HAS EXCELLENT
EQUATORWARD AND POLEWARD OUTFLOW CHANNELS. HOWEVER, TY 30W HAS
CROSSED INTO THE POOL OF COOLER (26-27 DEGREE CELSIUS) SEA SURFACE
TEMPERATURES WHICH ARE A PRODUCT OF UPWELLING CAUSED BY THE PASSAGE
OF TY TRAMI SEVERAL DAYS AGO. THESE COOLER SEA SURFACE TEMPERATURES
HAVE LED TO A RAPID DECREASE IN INTENSITY. TY 30W IS TRACKING
NORTHWESTWARD ALONG THE SOUTHWESTERN PERIPHERY OF THE SUBTROPICAL
RIDGE (STR) LOCATED TO THE NORTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. THROUGH TAU 48, TY 30W WILL CONTINUE TO TRACK NORTHWESTWARD AND
GRADUALLY TURN MORE NORTHWARD ALONG THE SOUTHWESTERN AND THEN WESTERN
PERIPHERY OF THE STR. BETWEEN TAU 48 AND 72, TY 30W WILL TRACK
NORTHEASTWARD AROUND AFOREMENTIONED STR AS ENVIRONMENTAL CONDITIONS
DETERIORATE AND TY 30W CONTINUES TO WEAKEN, REACHING AN INTENSITY OF
70 KNOTS BY TAU 72. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT WITH
A SMALL ACROSS-TRACK SPREAD. HOWEVER, THERE IS POOR AGREEMENT IN THE
ALONG-TRACK FORECAST SPEED, SPECIFICALLY AFTER TAU 48. COTC IS THE
WESTERN OUTLIER INDICATING A SLOWER TRACK SPEED WITH GFS AND HWRF THE
EASTERN OUTLIERS INDICATING A FASTER TRACK SPEED. HWRF AND COTC HAVE
A SPREAD OF 390 NM BY TAU 72. DUE TO THE DIFFERENCES IN THE
ALONG-TRACK SPEED AFTER TAU 48 THERE IS LOW CONFIDENCE IN THIS
PORTION OF THE JTWC FORECAST TRACK.
   C. AFTER TAU 72, TY 30W WILL INTERACT WITH AN APPROACHING
SHORTWAVE THROUGH AND ACCELERATE TO THE NORTHEAST AROUND THE
AFOREMENTIONED STR. COOLER SEA SURFACE TEMPERATURES OFFSET BY
ENHANCED POLEWARD OUTFLOW WILL LEAD TO A STEADY DECREASE IN
INTENSITY. TY 30W WILL ALSO BEGIN EXTRA-TROPICAL TRANSITION (ETT) BY
TAU 72 AND COMPLETE ETT BY TAU 96. MODEL GUIDANCE REMAINS IN GOOD
AGREEMENT, INDICATING A NORTHEASTWARD TRACK BUT SIGNIFICANT
DIFFERENCES IN ALONG-TRACK SPEED REMAIN. NOTABLY, CTCX AND ECMWF
HAVE A SPREAD OF 870 NM BY TAU 120 WITH CTCX THE SLOWER SOLUTION AND
ECMWF THE FASTER SOLUTION. THE JTWC FORECAST TRACK IS PLACED NEAR
THE MULTI-MODEL CONSENSUS, FAVORING THE FASTER SOLUTION. OVERALL,
THERE IS LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.//
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