Tropical Storm YUTU Advisory 10月24日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 31W (YUTU) WARNING NR 10//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 31W (YUTU), LOCATED APPROXIMATELY 243 NM EAST-
SOUTHEAST OF ANDERSEN AFB, GUAM, HAS TRACKED WEST-NORTHWESTWARD AT 09
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY SHOWS THE SYSTEM HAS DEVELOPED A WELL-DEFINED 23-NM
EYE AS FEEDER BANDS WRAPPED TIGHTER INTO A HIGHLY COMPACT AND DEEP
CENTRAL CONVECTION. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE EYE FEATURE, ADJUSTED FOR SLANT AND
SUPERIMPOSED OVER A MICROWAVE EYE IN THE 231734Z 37GHZ SSMIS PASS.
THE INITIAL INTENSITY OF 110 KNOTS IS AVERAGED FROM THE PGTW AND RJTD
DVORAK ESTIMATES OF T6.0/115KTS AND T5.5/102KTS, RESPECTIVELY, AND
REFLECTS THE CONTINUED RAPID INTENSIFICATION (RI). UPPER LEVEL
ANALYSIS INDICATES TY 31W IS IN A VERY FAVORABLE AREA WITH LOW (10-15
KNOT) VERTICAL WIND SHEAR (VWS) AND EXCELLENT RADIAL OUTFLOW WITH A
STRONG POLEWARD BIAS. ADDITIONALLY, ALONG-TRACK SEA SURFACE
TEMPERATURES (SST) AND OCEAN HEAT CONTENT (OHC) ARE HIGHLY CONDUCIVE.
THE CYCLONE IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A
DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE NORTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 31W IS EXPECTED TO TRACK WEST-NORTHWESTWARD UNDER THE STR
THROUGHOUT THE FORECAST. ENVIRONMENTAL CONDITIONS WILL REMAIN
FAVORABLE FOR RI WITH THE SYSTEM REACHING SUPER TYPHOON INTENSITY OF
130 KNOTS IN 12 HOURS, THEN A MORE GRADUAL INTENSIFICATION TO A PEAK
OF 150 KNOTS BY TAU 72. NUMERICAL MODEL GUIDANCE IS IN GOOD
AGREEMENT WITH MINIMAL SPREADING UP TO 150 NM BY TAU 72. A NOTABLE
RIGHT OF ENVELOPE OUTLIER IS HWRF. THERE IS HIGH CONFIDENCE IN THIS
PORTION OF THE JTWC TRACK FORECAST THAT IS LAID JUST LEFT OF
CONSENSUS TO OFFSET THE UNLIKELY POLEWARD TRACK OFFERED BY HWRF.
   C. BEYOND TAU 72, TY YUTU WILL SLOW DOWN AS IT APPROACHES A COL
AREA AHEAD OF A MIDLATITUDE TROUGH. VWS, SST, AND OHC VALUES WILL
REMAIN FAVORABLE. HOWEVER, POLEWARD OUTFLOW WILL DIMINISH NEAR THE
COL, RESULTING IN A SLIGHT WEAKENING TO 130 KNOTS BY TAU 120. THE
NUMERICAL MODEL GUIDANCE SIGNIFICANTLY SPREADS OUT TO OVER 680 NM BY
TAU 120 WITH CTCX ON THE RIGHT MARGIN OF THE ENVELOPE OFFERING A
SHARP AND EARLY RECURVATURE AND EGRR AND AFUM ON THE LEFT MARGIN
OFFERING A FLAT WESTWARD TRACK. IN VIEW OF THE WIDE SPREAD, THERE IS
LOW CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC TRACK FORECAST
THAT IS LAID JUST LEFT OF AND SLOWER THAN CONSENSUS TO OFFSET THE
UNLIKELY SHARP POLEWARD RECURVATURE OFFERED BY CTCX.//
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