Tropical Storm MANGKHUT Advisory Fri Sep 14

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 26W (MANGKHUT) WARNING
NR 26//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   SUPER TYPHOON 26W (MANGKHUT), LOCATED APPROXIMATELY 528 NM EAST
OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 11 KNOTS OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A
195NM DIAMETER CONVECTIVE CORE WITH A 30NM ROUND EYE. A 130656Z
SSMIS 91GHZ MICROWAVE IMAGE SUGGESTS THAT THE EYEWALL REPLACEMENT
CYCLE IS NEARING COMPLETION, LEAVING A BROADER EYE SURROUNDED BY THE
NEW PRIMARY EYEWALL. THE INITIAL INTENSITY IS ASSESSED TO REMAIN AT
145 KTS BASED ON MULTIAGENCY DVORAK CURRENT INTENSITY ESTIMATES
RANGING FROM T7.0 (140 KNOTS) TO T7.5 (155 KNOTS) AND A 130427Z
SATCON ESTIMATE OF 146 KTS. UPPER-LEVEL ANALYSIS CONTINUES TO
INDICATE A VERY FAVORABLE ENVIRONMENT WITH RADIAL OUTFLOW, ENHANCED
BY A TUTT CELL TO THE EAST, AND LOW VERTICAL WIND SHEAR.
ADDITIONALLY, WARM SST (29-30C) AND HIGH OCEAN HEAT CONTENT VALUES
ARE VERY FAVORABLE. STY 26W IS TRACKING WESTWARD UNDER THE STEERING
INFLUENCE OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) ENTRENCHED TO
THE NORTH.
 3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. STY 26W WILL TRACK WEST-NORTHWESTWARD ALONG THE SOUTHERN
PERIPHERY OF THE STR THROUGH THE FORECAST PERIOD WITH LANDFALL ALONG
THE NORTHEAST COAST OF LUZON AT ABOUT TAU 36, CONSISTENT WITH THE
PREVIOUS FORECAST’S TIMING. STY 26W WILL MAINTAIN STY INTENSITY
THROUGH TAU 36 UNDER VERY FAVORABLE ENVIRONMENTAL CONDITIONS. IT IS
POSSIBLE THAT STY 26W WILL RE-INTENSIFY SLIGHTLY IN THE AFTERMATH OF
THE EYEWALL REPLACEMENT CYCLE AS THE PRIMARY EYEWALL CONTRACTS.
AFTER TAU 36, STY 26W WILL WEAKEN SIGNIFICANTLY AS IT TRACKS OVER
THE MOUNTAINOUS REGION OF LUZON, RE-EMERGING OVER THE SOUTH CHINA
SEA (SCS) AROUND TAU 48 HAVING WEAKENED BUT STILL A SIGNIFICANT
TYPHOON AT 110 KTS. MODELS ARE IN CLOSE AGREEMENT, WITH ONLY 96 NM
OF SPREAD AT TAU 48, LENDING HIGH CONFIDENCE TO THIS PORTION OF THE
JTWC FORECAST TRACK.
   C. AFTER TAU 72, STY MANGKHUT WILL CONTINUE ON A WEST-
NORTHWESTWARD TRAJECTORY UNDER THE STEERING INFLUENCE OF THE STR.
THE SYSTEM WILL TRACK ACROSS THE SCS, PASSING SOUTH OF HONG KONG,
MAKING LANDFALL NEAR THE BORDER OF VIETNAM AND CHINA BY TAU 96. THE
SYSTEM WILL WEAKEN PRIOR TO TAU 96 AS SHEAR INCREASES, OUTFLOW
DECREASES, AND THE SYSTEM BEGINS TO INTERACT WITH LAND AND THE
LEIZHOU PENINSULA. THE SYSTEM WILL WEAKEN EVEN MORE RAPIDLY AFTER
MAKING LANDFALL AT TAU 96. THE DYNAMIC MODEL GUIDANCE AND ENSEMBLE
MODEL GUIDANCE REMAINS IN EXCEPTIONALLY TIGHT AGREEMENT, WITH ECMWF
AND THE ECMWF ENSEMBLE BEING SOUTHERN OUTLIERS, 100NM SOUTHWEST OF
THE MULTI-MODEL CONSENSUS AT TAU 96. THERE IS OVERALL HIGH
CONFIDENCE IN THE JTWC FORECAST TRACK.//
NNNN
NNNN