Tropical Storm YUTU Advisory Mon Oct 29

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 31W (YUTU) WARNING NR 32//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 31W (YUTU), LOCATED APPROXIMATELY 281 NM EAST-
NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 09 KNOTS
OVER THE PAST SIX HOURS. THE INITIAL POSITION IS PLACED WITH GOOD
CONFIDENCE USING ANIMATED MULTISPECTRAL SATELLITE IMAGERY WHICH
SHOWS A PARTIALLY CLOUD-FILLED 26 NM EYE. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY SHOWS THAT CLOUD TOP TEMPERATURES IN THE EYEWALL
HAVE COOLED OVER THE PAST SEVERAL HOURS. THE 90 KNOT INTENSITY
ESTIMATE IS CONSISTENT WITH PGTW/RJTD DVORAK CURRENT INTENSITY
ESTIMATES OF T5.0 (90 KNOTS) AND REFLECTS A PAUSE IN THE WEAKENING
TREND. THE SYSTEM IS IN A MARGINALLY FAVORABLE REGION WITH LOW (10-
15 KNOT) VERTICAL WIND SHEAR (VWS) AND WARM (28-29 CELSIUS) SEA
SURFACE TEMPERATURE BEING PARTIALLY OFFSET BY WEAK RADIAL OUTFLOW.
TY 31W IS TRACKING ALONG THE SOUTHERN PERIPHERY OF AN EAST-WEST
ORIENTED SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 31W WILL CONTINUE ON A WESTWARD TO WEST-SOUTHWESTWARD TRACK
AND MAKE LANDFALL ON LUZON SHORTLY AFTER TAU 12 WITH AN INTENSITY OF
ABOUT 85 KNOTS. AFTER MAKING LANDFALL, LAND INTERACTION WILL WEAKEN
THE SYSTEM SIGNIFICANTLY BEFORE IT EXITS LUZON INTO THE SOUTH CHINA
SEA (SCS) SHORTLY AFTER TAU 24. ONCE IN THE SCS, AN APPROACHING MID-
LATITUDE TROUGH WILL CREATE A BREAK IN THE STR AND ALLOW THE CYCLONE
TO TURN NORTHWARD AND RE-INTENSIFY TO 80 KNOTS BY TAU 72. MODEL
GUIDANCE IS IN TIGHT AGREEMENT WITH A 65NM SPREAD AT TAU 48 AND A
165NM SPREAD AT TAU 72. THE JTWC TRACK FORECAST IS PLACED CLOSE
TO THE CONSENSUS TRACK WITH LOW UNCERTAINTY IN THIS PORTION OF THE
JTWC FORECAST.
   C. AFTER TAU 72, TY 31W WILL CREST THE STR AXIS AND TRACK MORE
EAST-NORTHEASTWARD. HIGH VWS AND COOL CONTINENTAL AIR WILL REDUCE
THE INTENSITY TO 30 KNOTS BY TAU 120. AS IS COMMON WITH A RECURVING
TROPICAL CYCLONE, SPREAD IN THE MODEL GUIDANCE INCREASES
SIGNIFICANTLY AS THE DEGREE AND TIMING OF THE TURNING VARIES AMONG
THE MODELS. IN THE LATEST RUN, JGSM, COAMPS-GFS, AND (TO SOME
DEGREE) HWRF ARE NOT PREDICTING RECURVATURE BEFORE TAU 120 AND
DEPICT A MORE NORTHWESTWARD TRACK TOWARDS CHINA. THE REMAINING
MODELS ALL DEPICT A RECURVING TRACK, SIMILAR TO THE JTWC TRACK
FORECAST. THE SPREAD BETWEEN THE SOUTHERNMOST (COAMPS-GFS) AND
NORTHERNMOST (GALWEM) MODELS IS OVER 800 NM BY TAU 120, REFLECTING
HIGH UNCERTAINTY IN THE EXTENDED JTWC TRACK FORECAST.//
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