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I'm wondering if the NWS has changed it's parameters for Sev. Thunderstorm warnings. This was txmitted by NWS JAX this evening. Quick look at the Hail size and wind speed ...Should qualify for a Severe Thunderstorm Warning. "Significant Weather Alert"... is this something new...and Deadly? WWUS82 KJAX 122350 SPSJAX SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE JACKSONVILLE FL 750 PM EDT SAT AUG 12 2006 FLZ022-023-130030- BAKER-COLUMBIA- 750 PM EDT SAT AUG 12 2006 ...A SIGNIFICANT WEATHER ALERT HAS BEEN ISSUED FOR BAKER AND COLUMBIA COUNTIES FOR STRONG WINDS AND SMALL HAIL VALID UNTIL 830 PM EDT... AT 750 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM CENTERED 7 MILES NORTHWEST OF OLUSTEE...OR 9 MILES NORTHEAST OF LAKE CITY...MOVING EAST AT 10 MPH. THIS STRONG THUNDERSTORM WILL ALSO AFFECT AREAS AROUND OLUSTEE AND SANDERSON THROUGH 830 PM EDT. HAIL UP TO ONE HALF INCH IN DIAMETER AND GUSTY WINDS OF 45 TO 55 MPH CAN BE EXPECTED ALONG WITH POSSIBLE MINOR DAMAGE. REPORT DAMAGE TO THE NEAREST LAW ENFORCEMENT AGENCY OR YOUR COUNTY EMERGENCY MANAGEMENT...OR YOU CAN CALL THE NATIONAL WEATHER SERVICE IN JACKSONVILLE DIRECTLY AT 1-800-499-1594. $$ PETERSON http://www.srh.noaa.gov/productview.php?pil=SPSJAX&max=61 As of this edit...0025Z, there have been no SVR Thunderstorm Warnings for this particular Storm or County.~danielw |
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Nah, that doesn't quite meet severe thunderstorm warning criteria, though it's close. They go with dime-sized hail -- or 3/4" in diameter -- and winds of 58mph or higher. For what they mentioned in the special statement, the difference likely won't be noticeable to most people, but my guess is they didn't think things would quite make it to severe criteria. |
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I found the answer to the "Significant Weather Alert" Criteria is as follows: "Significant Weather Alert" - Bulletin issued to provide information about thunderstorms causing any of the following problems: Unusually frequent/intense cloud-to-ground lightning Winds 40 to 50 mph Hail smaller than pennies Heavy rain causing significant visibility restrictions...especially near major highways during high traffic times... or ponding of water on roadways. Product Identifiers - ___SPS___ or WWUS82 (Blank spaces are for the NWS Office Identifier~danielw) This product is updated... as conditions warrant using another "Significant Weather Alert". http://www.srh.noaa.gov/ffc/html/whatissps.shtml So this is issued when a heavy Thunderstorm does NOT meet Severe Thunderstorm criteria~danielw "Severe Thunderstorm Warning" - Bulletin issued when a severe thunderstorm has actually been observed by spotters or indicated on radar, and is occurring or imminent in the warning area. A "severe" thunderstorm is one that produces: Hail the size of pennies or larger, or damaging winds (winds above 58 mph). http://www.srh.noaa.gov/ffc/html/whatissvr.shtml |