Tropical Storm YUTU Advisory Sun Oct 28

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 31W (YUTU) WARNING NR
28//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   SUPER TYPHOON (STY) 31W (YUTU), LOCATED APPROXIMATELY 501 NM EAST-
NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 10 KNOTS
OVER THE PAST SIX HOURS. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON A 45-NM RAGGED EYE IN ANIMATED MULTISPECTRAL
SATELLITE IMAGERY (MSI) WHICH ALSO SHOWS THE DEEP CONVECTION HAS
ERODED ON THE EASTERN SIDE OF THE CYCLONE. THE INITIAL INTENSITY OF
130 KNOTS FOLLOWS MULTI-AGENCY DVORAK ESTIMATES OF T6.5-T7.0 (127-
140 KNOTS). THE ENVIRONMENT IS MARGINALLY FAVORABLE WITH LOW (10-15
KNOT) VERTICAL WIND SHEAR (VWS), GOOD RADIAL OUTFLOW, AND WARM SEA
SURFACE TEMPERATURE (28-29 CELSIUS) BEING OFFSET BY DRY AIR FROM THE
WEST WRAPPING AROUND TO THE EASTERN PERIPHERY OF THE CYCLONE. STY
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. STY 31W WILL CONTINUE TO TRACK WESTWARD TO WEST-SOUTHWESTWARD
TOWARD LUZON, MAKE LANDFALL SHORTLY AFTER TAU 36 AND RE-EMERGE INTO
THE SOUTH CHINA SEA (SCS) AFTER TAU 48. THE SYSTEM IS EXPECTED TO
WEAKEN TO 115 KNOTS PRIOR TO LANDFALL AS DRY AIR CONTINUES TO IMPACT
THE CYCLONE, WEAKEN SIGNIFICANTLY OVER LUZON, AND RE-INTENSIFY
SLIGHTLY IN THE SCS. THE INTENSITY FORECAST CLOSELY FOLLOWS THE HWRF
INTENSITY FORECAST, WHICH HAS A TRACK VERY SIMILAR TO THE JTWC
FORECAST TRACK. THE JTWC TRACK FORECAST IS CLOSE TO THE CONSENSUS
TRACK. WITH SPREAD IN THE MODELS OF ABOUT 150 NM AT TAU 72,
UNCERTAINTY IN THE JTWC TRACK FORECAST IS LOW FOR THIS PORTION OF
THE FORECAST.
   C. BEYOND TAU 72, AN APPROACHING MID-LATITUDE TROUGH WILL WEAKEN
THE STR AND ALLOW STY 31W TO RECURVE NORTHWARD. ENVIRONMENTAL
CONDITIONS ARE EXPECTED TO BE MARGINALLY FAVORABLE WITH STRONG
RADIAL OUTFLOW BEING OFFSET BY HIGH VWS AND THE ENTRAINMENT OF COOL,
DRY AIR. EVERY NUMERICAL MODEL MEMBER IN THE CONSENSUS PREDICTS
RECURVATURE BUT, BY TAU 120, THE SPREAD IS ABOUT 400 NM DUE TO
DIFFERENCES IN THE TIMING AND DEGREE OF RECURVATURE. BASED ON THIS
SPREAD, UNCERTAINTY IS LOW IN THE EXTENDED PORTION OF THE JTWC
TRACK FORECAST.//
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