Tropical Storm TRAMI Advisory пн, 24.09.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 28W (TRAMI)
WARNING NR 13//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 28W (TRAMI), LOCATED APPROXIMATELY 563 NM SOUTH-SOUTHEAST
OF KADENA AB, HAS TRACKED WEST-NORTHWESTWARD AT 12 KNOTS OVER THE
PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS
WARMING CLOUD TOPS AND A SMALL 7NM ROUND EYE, WHICH SUPPORTS THE
CURRENT POSITION WITH HIGH CONFIDENCE. AN EYEWALL REPLACEMENT CYCLE
WAS ONGOING IN A 231204Z MHS 89GHZ IMAGE, WHICH SHOWED DOUBLE
EYEWALLS SURROUNDED BY A MOAT. A MORE RECENT 231650Z AMSR-2 89GHZ
IMAGE SHOWS THE PRIMARY EYEWALL HAS ERODED AS THE SECONDARY EYEWALL
BEGINS TO PREDOMINATE. THE INITIAL INTENSITY OF 28W IS ESTIMATED AT
120 KTS, BETWEEN ALL AGENCY DVORAK CURRENT INTENSITY ESTIMATES OF
T6.0 (115 KTS) AND A 231711Z SATCON ESTIMATE OF 127 KTS. THE EYEWALL
REPLACEMENT CYCLE HAS TEMPERED THE RECENT RAPID INTENSIFICATION
TREND AS THE SECONDARY EYEWALL STARVES THE PRIMARY EYEWALL OF
INFLOW, AND THE LATEST INTENSITY ESTIMATE REFLECTS ONLY 5 KTS OF
INTENSIFICATION IN THE LAST 6 HOURS. UPPER-LEVEL ANALYSIS INDICATES
A FAVORABLE ENVIRONMENT WITH NEAR-RADIAL OUTFLOW, ENHANCED BY A TUTT
CELL TO THE NORTHEAST AND A MIDLATITUDE TROUGH TO THE NORTH, AND LOW
VERTICAL WIND SHEAR. SEA SURFACE TEMPERATURES ARE FAVORABLE AT 29C.
TY 28W IS TRACKING WESTWARD ALONG THE SOUTHERN PERIPHERY 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. TY TRAMI IS FORECAST TO TRACK WEST-NORTHWESTWARD UNDER THE
STEERING INFLUENCE OF THE AFOREMENTIONED STR THROUGH TAU 24. AFTER
TAU 24, A MIDLATITUDE SHORTWAVE TROUGH WILL MOVE INTO THE EAST CHINA
SEA (ECS) AND JAPAN REGION, ERODING THE STR. AS THE TROUGH PASSES
AND ERODES THE STR, THE FORWARD MOTION OF 28W WILL SLOW DRAMATICALLY
AND IT WILL TURN POLEWARD. THE MAJORITY OF MODELS AND THE MULTI-
MODEL CONSENSUS SHOW A SMALL KINK IN THE TRACK TO THE NORTH. GFS,
HWRF, AND THE MOST RECENT RUN OF ECMWF ARE THE OUTLIERS AND SHOW A
MORE DRAMATIC TURN TO THE NORTH, WITH ECMWF STARTING THE NORTHWARD
TURN AT TAU 36. THIS IS A SHIFT IN PREDICTED TRACK FOR ECMWF, WHICH
LAST RUN SHOWED A LESS DRASTIC TURN TO THE NORTH AND WAS MORE IN
LINE WITH THE MULTI-MODEL CONSENSUS. TRACK SPEEDS ARE EXPECTED TO
REMAIN SLOW THROUGH TAU 72 AS THE STR SLOWLY REBUILDS TO THE NORTH
AND THE SYSTEM RETURNS TO A WEST-NORTHWESTWARD COURSE. THERE IS A
155 NM SPREAD IN MODELS AT TAU 72, AND GIVEN THE RECENT SHIFT IN
ECMWF MODEL TRACK, CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST
TRACK IS LOW. RAPID INTENSIFICATION IS INDICATED IN NUMERICAL MODEL
GUIDANCE THROUGH TAU 24. AFTER THE EYEWALL REPLACEMENT CYCLE
CONCLUDES AND THE SECONDARY EYEWALL CONTRACTS, THE SYSTEM IS
EXPECTED TO INTENSIFY TO SUPER TYPHOON STRENGTH BY TAU 12 UNDER VERY
FAVORABLE CONDITIONS, WITH A PEAK INTENSITY OF 145 KNOTS ANTICIPATED
BY TAU 24. GRADUAL WEAKENING WILL START AFTER TAU 48 AS
ENVIRONMENTAL CONDITIONS DEGRADE.
   C. THROUGH TAU 120, TY 28W WILL MOVE NORTHWESTWARD UNDER THE
REBUILT STR. TOWARDS THE END OF THE FORECAST PERIOD, A MIDLATITUDE
SHORTWAVE TROUGH WILL APPROACH THE ECS. THE NORTHERN OUTLIERS OF
GFS, HWRF, AND ECMWF THEN SHOW A MORE NORTH-NORTHWESTWARD TRACK IN
RESPONSE TO THIS TROUGH ERODING THE STR. THE JTWC OFFICIAL FORECAST
HAS BEEN SHIFTED SLIGHTLY TO THE NORTHEAST TO REFLECT THE SHIFTING
ECMWF GUIDANCE, BUT STILL IS PLACED CLOSE TO THE MULTI-MODEL
CONSENSUS WITH A TRACK TOWARD ISHIGAKI-JIMA. THERE IS LOW CONFIDENCE
IN THIS PORTION OF THE JTWC TRACK FORECAST DUE TO THE 382 NM SPREAD
IN MODEL GUIDANCE AT TAU 120. THE GRADUAL WEAKENING TREND IS
FORECAST TO CONTINUE THROUGH TAU 120.//
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