Tropical Storm KONG-REY Advisory Wed Oct 03

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 30W (KONG-REY) WARNING NR 21//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 30W (KONG-REY), LOCATED APPROXIMATELY 398 NM SOUTH-
SOUTHEAST OF KADENA AB, HAS TRACKED NORTHWESTWARD AT 09 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY SHOWS THAT DEEP CONVECTION HAS CONTINUED TO STRUGGLE, WITH
TWO PARTIAL EYEWALLS STILL APPARENT TO THE SOUTH.  THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE 9 NM EYE IN EIR
IMAGERY. THE INITIAL
INTENSITY OF 125 KNOTS IS HEDGED BETWEEN THE PGTW AND RJTD DVORAK
CURRENT INTENSITY ESTIMATES OF T6.0 (115 KTS) AND THE KNES ESTIMATE
OF T6.5 (127 KTS), AS WELL AS A 022228Z SATCON ESTIMATE OF 130 KTS.
ENVIRONMENTAL ANALYSIS SHOWS THAT TY 30W IS EXPERIENCING FAVORABLE
VERTICAL WIND SHEAR (10 TO 15 KNOTS) ALONG WITH EXCELLENT
EQUATORWARD OUTFLOW AND GOOD POLEWARD OUTFLOW, ALTHOUGH OUTFLOW INTO
THE TUTT CELL TO ITS SOUTHEAST HAS SLACKENED OVER THE PAST 6 HOURS.
TY 30W HAS CROSSED INTO THE POOL OF COOLER (26-27 DEGREE CELSIUS)
SEA SURFACE TEMPERATURES RESULTING FROM UPWELLING GENERATED BY TY
TRAMI SEVERAL DAYS PRIOR, LEADING TO WEAKENING. 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
ALONG THE SOUTHWESTERN PERIPHERY OF THE STR. BETWEEN TAU 48 AND 72,
TY 30W WILL ROUND THE AXIS OF THE AFOREMENTIONED STR AND BEGIN
MOVING TO THE NORTHEAST. IN THE NEAR TERM, TY 30W WILL LOSE ITS
FAVORABLE ORIENTATION WITH RESPECT TO THE TUTT CELL TO THE SOUTHEAST
AND TROUGH TO THE NORTH, DECREASING OUTFLOW. THE DIMINISHED OUTFLOW
AND COOLER SSTS WILL CAUSE TY 30W TO WEAKEN TO 75 KTS BY TAU 48.
HOWEVER, THERE MAY BE SHORT-TERM INTENSITY FLUCTUATIONS AS THE NEW
PRIMARY EYEWALL CONTRACTS. ADDITIONALLY, TY 30W WILL TAP INTO
ANOTHER PASSING MIDLATITUDE TROUGH AT TAU 48, TEMPORARILY ENHANCING
OUTFLOW AND SLOWING THE WEAKENING TREND. DYNAMIC MODEL GUIDANCE
REMAINS IN GOOD AGREEMENT THROUGH TAU 48 WITH A SPREAD OF 125 NM.
HOWEVER, MODEL TRACKERS DIVERGE AFTER TAU 48 AT THE POINT OF THE
RECURVE AND HAVE A SPREAD OF 396 NM BY TAU 72. GALWEM, NAVGEM, AND
COAMPS-NAVGEM ARE THE WESTERN OUTLIERS AND PREDICT SLOWER MOTION.
HWRF, COAMPS-GFS, AND GFS ARE THE EASTERN OUTLIERS AND PREDICT A
TIGHTER RECURVE AND SIGNIFICANT ACCELERATION AS TY 30W ROUNDS THE
STR AXIS. THE JTWC FORECAST IS PLACED NEAR BUT SLIGHTLY TO THE EAST
OF THE MULTI-MODEL CONSENSUS. THERE IS OVERALL HIGH CONFIDENCE IN
THIS PORTION OF THE JTWC FORECAST TRACK UNTIL TAU 48, ALTHOUGH
UNCERTAINTY INCREASES AT TAU 72.
   C. AFTER TAU 72, TY 30W WILL ACCELERATE TO THE NORTHEAST
INFLUENCED BY THE PREVAILING MIDLATITUDE WESTERLIES. BY THIS TIME,
TY 30W WILL HAVE MOVED OVER EVEN COOLER SSTS BELOW 26 DEGREES
CELSIUS. AS TY 30W BECOMES FIRMLY EMBEDDED IN THE TROUGH, SUFFERS
FROM THE INCREASED VWS ASSOCIATED WITH THE TROUGH, AND TRACKS OVER
VERY COOL SSTS, IT WILL WEAKEN RAPIDLY. BETWEEN TAU 72 AND 96, LAND
INTERACTION WITH THE MOUNTAINOUS KOREAN PENINSULA WILL ALSO
CONTRIBUTE TO WEAKENING. TY 30W WILL BEGIN EXTRA-TROPICAL TRANSITION
(ETT) WITH AN EXPANDING WIND FIELD BY TAU 72 AS IT INTERACTS WITH
THE MIDLATITUDE WESTERLIES, AND IS FORECAST TO COMPLETE ETT BY TAU
96. DYNAMIC MODEL GUIDANCE IS IN AGREEMENT THAT TY 30W WILL TRACK TO
THE NORTHEAST AFTER TAU 72, BUT THERE ARE SIGNIFICANT DIFFERENCES IN
ALONG-TRACK SPEED, WITH A SPREAD OF 1053 NM AT TAU 120. THEREFORE,
THERE IS LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.//
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