Tropical Storm YUTU Advisory 10月25日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 31W (YUTU) WARNING NR
14//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   SUPER TYPHOON (STY) 31W (YUTU), LOCATED APPROXIMATELY 30 NM
WEST-NORTHWEST OF SAIPAN, HAS TRACKED NORTHWESTWARD AT 11 KNOTS OVER
THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
SHOWS A WELL DEFINED EYE WITH DEEP CONVECTION AROUND IT. HOWEVER, THE
COLDEST CLOUD TOPS HAVE SLIGHTLY WARMED OVER THE PAST SEVERAL HOURS.
THE INITIAL POSITION IS BASED ON A 241800Z HIMAWARI INFRARED
SATELLITE IMAGE WHICH SHOWS THE 20NM WIDE EYE. THE INITIAL INTENSITY
OF 150 KNOTS IS HEDGED SLIGHTLY BELOW DVORAK CURRENT INTENSITY (CI)
ESTIMATES OF T7.5 (155 KNOTS) FROM PGTW, RJTD, AND KNES BASED ON A
241608Z AMSR2 89GHZ MICROWAVE IMAGE SHOWING CONCENTRIC EYEWALLS
INDICATING AN EYEWALL REPLACEMENT CYCLE (ERC). ENVIRONMENTAL ANALYSIS
SHOWS STY 31W IS EXPERIENCING FAVORABLE VERTICAL WIND SHEAR (10 TO 15
KNOTS) AND HAS EXCELLENT RADIAL OUTFLOW. SEA SURFACE TEMPERATURES
ALSO REMAIN FAVORABLE, NEAR 30 DEGREES CELSIUS. STY 31W IS TRACKING
ALONG THE SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) LOCATED
TO THE NORTHEAST AND THE SOUTHEASTERN PERIPHERY OF AN STR LOCATED TO
THE NORTHWEST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE. HOWEVER, MAXIMUM SIGNIFICANT
WAVE HEIGHT HAS BEEN LOWERED TO 30 FEET BASED ON A 241211Z ALTIMETRY
PASS SHOWING 27 FEET SOUTH OF TINIAN.
   B. THE CURRENT ERC WILL RESULT IN A SLIGHT WEAKENING IN THE SHORT
TERM. STY 31 WILL CONTINUE TO TRACK TO THE NORTHWEST WHILE POSITIONED
BETWEEN THE AFOREMENTIONED STRS. MODEL GUIDANCE REMAINS IN FAIRLY
GOOD AGREEMENT THOUGH TAU 24, INDICATING A NORTHWESTWARD TRACK, BUT
QUICKLY DIVERGES AFTER THAT WITH A SPREAD OF 380 NM BY TAU 72. AT TAU
72 JGSM IS THE OUTLIER TO THE SOUTHWEST INDICATING A WESTWARD TRACK
WITH NVGM THE OUTLIER TO THE NORTHEAST INDICATING A RECURVE SCENARIO.
THE JTWC FORECAST TRACK IS PLACED NEAR THE MULTI-MODEL CONSENSUS IN
THE MIDDLE GROUP OF A TRIFURCATION, FAVORING THE ECMWF AND GFS
TRACKERS. DUE TO WIDE SPREAD IN MODEL GUIDANCE THERE IS LOW
CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.
   C. BEYOND TAU 72 THE TRIFURCATION IN THE MODELS CONTINUES. JGSM,
EGRR, AND AFUM INDICATE A WEST-SOUTHWESTWARD TRACK WITH NVGM AND CTCX
INDICATING A NORTHEASTWARD TRACK. ECMWF, GFS, AND HWRF INDICATE A
NORTHWESTWARD TRACK. NVGM AND EGRR ARE AT THE EDGES OF THE MODEL
ENVELOPE AND HAVE A MASSIVE SPREAD OF NEARLY 1900 NM BY TAU 120. THE
JTWC FORECAST TRACK IS PLACED TO THE SOUTHWEST OF THE MULTI-MODEL
CONSENSUS, FAVORING THE GFS AND ECMWF SOLUTIONS. DUE TO THE WIDE
SPREAD IN MODEL GUIDANCE THERE IS LOW CONFIDENCE IN THIS PORTION OF
THE JTWC FORECAST TRACK.//
NNNN
NNNN