Tropical Storm NARI Advisory 7月26日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 07 (SEVEN) WARNING
NR 004//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM 07W (SEVEN), LOCATED APPROXIMATELY 278 NM
WEST-NORTHWEST OF CHICHI JIMA, HAS TRACKED NORTHWARD AT 10 KNOTS OVER
THE PAST SIX HOURS. THE CURRENT POSITION IS BASED ON RECENT AGENCY
SATELLITE FIXES FROM VARIOUS REPORTING AGENCIES AND MICROWAVE
SATELLITE IMAGERY INCLUDING A 251651Z ATMS PASS, WHICH SHOWS A
PARTIALLY-EXPOSED LOW LEVEL CIRCULATION (LLCC) WITH CONVECTION
LARGELY OFFSET TO THE EAST. THE INTENSITY IS SET AT 35 KNOTS BASED ON
A 251225Z ASCAT METOP-C PASS INDICATING AN EXTENSIVE AREA OF 30-35
KNOT WINDS TO THE EAST AND NORTH OF THE LOW LEVEL CIRCULATION CENTER.
ADDITIONALLY, A 251940Z ADT ESTIMATE OF 35 KNOTS FURTHER SUPPORTS
THIS CONCLUSION. TS 07W HAS CONTINUED POLEWARD OVER THE PAST SIX
HOURS ALONG THE PERIPHERY OF A SUBTROPICAL RIDGE TO THE EAST.
PERSISTENT, MODERATE SOUTHWESTERLY VERTICAL WIND SHEAR (VWS)
ASSOCIATED WITH THE FLOW AROUND AN UPPER-LEVEL LOW TO THE WEST HAS
KEPT DEEP CONVECTION CONFINED TO THE EASTERN AND NORTHERN PORTIONS OF
THE STORM CIRCULATION. WARM SEA SURFACE TEMPERATURES (28-29C) AND
GOOD POLEWARD OUTFLOW ALOFT HAVE COUNTERED THE IMPACT OF THE
PERSISTENT VWS, ENABLING THE SYSTEM TO MAINTAIN OVER THE PAST SEVERAL
HOURS.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS
WARNING.
   B. TS 07W WILL CONTINUE TRACKING POLEWARD THROUGH TAU 36, AND
SUBSEQUENTLY TURN EASTWARD AS IT ROUNDS THE SUBTROPICAL STEERING
RIDGE AXIS. PASSAGE OVER WARM WATER AND FAVORABLE OUTFLOW SHOULD
ALLOW THE SYSTEM TO MAINTAIN WEAK TROPICAL STORM INTENSITY FOR THE
NEXT 24 HOURS DESPITE THE MODERATE TO STRONG SHEAR ALONG THE FORECAST
TRACK. AFTER TAU 24, PASSAGE OVER LAND WILL INDUCE PRONOUNCED WEAKENING.
   C. TS 07W WILL DISSIPATE BY TAU 72 DUE TO PASSAGE OVER LAND AND
COOL WATER (24-26 DEGREES CELSIUS). THE CIRCULATION IS EXPECTED TO
REMAIN SEPARATE FROM THE MID-LATITUDE FLOW PATTERN AS IT DISSIPATES,
SO EXTRATROPICAL TRANSITION IS NOT ANTICIPATED. NUMERICAL MODEL
GUIDANCE REMAINS IN GOOD AGREEMENT REGARDING THE STEERING SCENARIO,
LENDING HIGH CONFIDENCE TO THE CURRENT JTWC TRACK FORECAST.//
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