Tropical Storm HAGIBIS Advisory 10月7日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 20W (HAGIBIS) WARNING NR 007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 20W (HAGIBIS), LOCATED APPROXIMATELY 368 NM EAST-
NORTHEAST OF ANDERSEN AFB, GUAM, HAS TRACKED WEST-NORTHWESTWARD AT
14 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY DEPICTS A RAPIDLY CONSOLIDATING SYSTEM WITH A
CENTRAL DENSE OVERCAST FEATURE AND DEEP CONVECTIVE BANDING. A
061742Z SSMIS 91GHZ IMAGE INDICATES TIGHTLY-CURVED BANDING WRAPPING
INTO A SMALL MICROWAVE EYE FEATURE, WHICH, ALONG WITH EIR, SUPPORTS
THE CURRENT POSITION WITH GOOD CONFIDENCE. UPPER-LEVEL ANALYSIS
INDICATES RADIAL OUTFLOW WITH LOW VERTICAL WIND SHEAR. SST VALUES OF
30-31C AND HIGH OCEAN HEAT CONTENT VALUES ALSO SUPPORT SIGNIFICANT
INTENSIFICATION. THE CURRENT INTENSITY IS ASSESSED AT 65 KNOTS BASED
ON DVORAK INTENSITY ESTIMATES OF T4.0 (65 KNOTS) FROM PGTW, KNES AND
RJTD. THE SYSTEM IS TRACKING ALONG THE SOUTHERN PERIPHERY OF A DEEP-
LAYERED SUBTROPICAL RIDGE (STR) ENTRENCHED TO THE NORTH.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE. ADDITIONALLY, THIS
FORECAST REMAINS CONSISTENT WITH THE PREVIOUS JTWC FORECAST.
   B. TY 20W IS FORECAST TO TRACK WEST-NORTHWESTWARD TO
NORTHWESTWARD THROUGH TAU 72 UNDER THE STEERING INFLUENCE OF THE STR
POSITIONED TO THE NORTH. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO
REMAIN VERY FAVORABLE THROUGH THE FORECAST PERIOD WITH ROBUST
OUTFLOW, WARM SST AND HIGH OCEAN HEAT CONTENT VALUES SUPPORTING
PERIODS OF RAPID INTENSIFICATION (RI). JTWC INTENSITY GUIDANCE
CONTINUES TO INDICATE POTENTIAL FOR RI WITHIN THE NEXT 36 HOURS.
THIS FORECAST INDICATES AN 85-95 KNOT SYSTEM IMPACTING THE NORTHERN
MARIANAS. OVERALL, THERE IS HIGH CONFIDENCE IN THE JTWC TRACK
FORECAST THROUGH TAU 24 WITH A 30 NM SPREAD IN SOLUTIONS AT
TAU 24. AFTER TAU 24, TY 20W WILL CONTINUE TO INTENSIFY UNDER
FAVORABLE CONDITIONS. IMPROVED POLEWARD OUTFLOW WILL AID IN BOOSTING
THE INTENSITY TO SUPER TYPHOON STRENGTH BY TAU 72. NUMERICAL MODELS
DIVERGE SO THERE IS INCREASING UNCERTAINTY IN THE LATER TAUS WITH A
213 NM SPREAD IN SOLUTIONS AT TAU 72.
   C. IN THE EXTENDED PERIOD, TY 20W WILL GENERALLY TRACK
NORTHWESTWARD TO NORTH-NORTHWESTWARD TOWARD A BREAK IN THE STR
ASSOCIATED WITH A DEEP, DYNAMIC SHORTWAVE TROUGH FORECAST TO DEEPEN
OVER WESTERN JAPAN. THERE IS INCREASING UNCERTAINTY AS THE NUMERICAL
MODEL GUIDANCE DIVERGES WITH A 373 NM SPREAD IN SOLUTIONS AT TAU
120. THE 06/12Z ECMWF ENSEMBLE STRIKE PROBABILITY PRODUCT ALSO
INDICATES INCREASING UNCERTAINTY IN THE TIMING OF THE RECURVE SOUTH
OF WESTERN JAPAN, THEREFORE, THERE IS LOW OVERALL CONFIDENCE IN THE
JTWC TRACK FORECAST. NAVGEM (NVGI) AND GFS (AVNI) REMAIN OUTLIERS ON
THE EASTERN EDGE OF THE AIDS ENVELOPE.//
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