Tropical Storm KONG-REY Advisory Tue Oct 02

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 30W (KONG-REY) WARNING NR 17//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   SUPER TYPHOON 30W (KONG-REY), LOCATED APPROXIMATELY 599 NM SOUTH-
SOUTHEAST OF KADENA AB, HAS TRACKED WEST-NORTHWESTWARD AT 09
KNOTS OVER THE PAST SIX HOURS. ENHANCED INFRARED (EIR) SATELLITE
IMAGERY SHOWS CLOUD TOPS HAVE WARMED SLIGHTLY OVER THE PAST SIX
HOURS. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON
A 15 NM ROUND EYE IN THE EIR SATELLITE IMAGERY. THE INITIAL
INTENSITY OF 140 KNOTS IS IN AGREEMENT WITH THE DVORAK CURRENT
INTENSITY ESTIMATES OF T7.0 (140 KTS) FROM RJTD AND KNES, AND BELOW
THE PGTW ESTIMATE OF T7.5 (155 KTS). WHILE VERTICAL WIND SHEAR (VWS)
IS LOW (5-10 KTS), THE POLEWARD OUTFLOW CHANNEL TO THE NORTH HAS
WEAKENED. AN EYEWALL REPLACEMENT CYCLE IS ALSO POSSIBLY ONGOING,
BASED ON A FORMATIVE SECONDARY EYEWALL AND MOAT FEATURE IN A 012153Z
SSMIS 91GHZ IMAGE, WHICH COULD LEAD TO SHORT-TERM WEAKENING. SEA
SURFACE TEMPERATURES REMAIN FAVORABLE FOR CONTINUED INTENSIFICATION
BETWEEN 29-30 DEGREES CELSIUS. THE CYCLONE CONTINUES TO TRACK ALONG
THE SOUTHWESTERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR)
TO ITS NORTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. THROUGH TAU 72, STY 30W WILL CONTINUE TO TRACK NORTHWESTWARD
ALONG THE SOUTHWESTERN PERIPHERY OF THE STR. STY 30W IS FORECAST TO
MAINTAIN ITS CURRENT INTENSITY THROUGH TAU 12, THEN BEGIN TO WEAKEN
AS THE MIDLATITUDE TROUGH TO THE NORTH MOVES WESTWARD AND IS NO
LONGER ENHANCING OUTFLOW. THE POSSIBLE EYEWALL REPLACEMENT CYCLE MAY
ALSO LEAD TO SHORT-TERM INTENSITY FLUCTUATIONS, WITH INITIAL
WEAKENING AND LATER STRENGTHENING POSSIBLE AS THE PRIMARY EYEWALL IS
STARVED OF INFLOW THEN THE SECONDARY EYEWALL CONTRACTS.
ADDITIONALLY, AFTER TAU 24, STY 30W WILL MOVE INTO AN AREA OF COOLER
(26-27 C) SEA SURFACE TEMPERATURES AND SUBOPTIMAL OCEAN HEAT CONTENT
THAT WAS CHURNED UP BY THE QUASISTATIONARY PERIOD OF STY 28W SEVERAL
DAYS PRIOR, CONTRIBUTING TO THE WEAKENING TREND. NUMERICAL MODEL
GUIDANCE IS IN EXCELLENT AGREEMENT, WITH 100 NM OF SPREAD BY TAU 48,
LENDING HIGH CONFIDENCE TO THIS PORTION OF THE JTWC TRACK FORECAST.
THE INTENSITY FORECAST IN THE NEAR TERM REMAINS ON THE HIGH SIDE OF
MESOSCALE MODEL INTENSITY GUIDANCE.
   C. AFTER TAU 72, TY 30W WILL BEGIN TO GRADUALLY ROUND THE STR
AXIS, TRACKING NORTH-NORTHEASTWARD BY TAU 120, ALTHOUGH NUMERICAL
MODELS VARY GREATLY IN THEIR DEPICTIONS OF THE PLACEMENT AND TIMING
OF THE RECURVE. NAVGEM IS STILL THE WESTERNMOST OUTLIER, THOUGH IT
HAS SHIFTED CLOSER TO THE MULTI-MODEL CONSENSUS. ECMWF AND GALWEM
ARE ALSO WEST OF THE MULTI-MODEL CONSENSUS, TAKING LONGER TO
COMPLETE THE RECURVE. HWRF, COAMPS-GFS, AND GFS CONTINUE TO BE TO
THE EAST OF THE MULTI-MODEL CONSENSUS AND PREDICT A TIGHTER RECURVE,
AND ALSO ACCELERATE THE SYSTEM FURTHER INTO THE SEA OF JAPAN AT TAU
120. THE MAJOR VARIATIONS BETWEEN MODELS ARE IN TRACK SPEED. THE
JTWC TRACK FORECAST IS PLACED CLOSE TO THE MULTIMODEL CONSENSUS.
BEFORE TAU 96, STY 30W WILL MOVE INTO COOLER WATERS BELOW 26C, WHILE
A MIDLATITUDE TROUGH MOVES OVER MANCHURIA, ALLOWING STY 30W TO TAP
INTO THE MIDLATITUDE WESTERLIES AND AGAIN DEVELOP A POLEWARD OUTFLOW
CHANNEL. THE ENHANCED OUTFLOW WILL SOMEWHAT OFFSET THE LAND
INTERACTION WITH THE KOREAN PENINSULA, COOLER SSTS, AND HIGHER VWS
ASSOCIATED WITH THE TROUGH PROVIDING AN OTHERWISE UNFAVORABLE
ENVIRONMENT. AT TAU 120, AS STY 30W ACCELERATES POLEWARD AND
INTERACTS WITH THE APPROACHING TROUGH, IT WILL BEGIN EXTRATROPICAL
TRANSITION. THE INTENSITY FORECAST IN THE LATE TERM IS HEDGED
SLIGHTLY ABOVE THE MULTI-MODEL INTENSITY CONSENSUS. GIVEN THE ALONG-
TRACK MODEL SPREAD OF 970 NM BY TAU 120, CONFIDENCE IN THIS PORTION
OF THE JTWC TRACK FORECAST IS LOW.//
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