MAY1997 VOLUME 39 NUMBER 5 STORSTORMM DATDATAA AND UNUSUALWEATHER PHENOMENA WITH LATE REPORTS AND CORRECTIONS NATIONALOCEANIC AND NATIONALENVIRONMENTALSATELLITE NATIONALCLIMATIC DATACENTER noaa ATMOSPHERIC ADMINISTRATION DATA, AND INFORMATION SERVICE ASHEVILLE, N.C. Cover:AphotographoftheJarrell,TexasF5tornadoasitwasapproachingthetownofJarrell,TX.Thetornadowasspawnedbyasupercell thunderstormwhichformedalongthedryline(alineofsharpcontrastbetweenmoistanddryair).ThetornadotrackedsouththroughtheDoubleCreek Estatessubdivisionwhereitleveledhousesandkilled27poeple.(PhotocourtesyofScottBeckwith,JarrellFarmSupply,Jarrell,Texas) TABLEOF CONTENTS Page OutstandingStormsoftheMonth.................................................5 StormDataandUnusualWeatherPhenomena..........................................9 STORMDATA (ISSN0039-1972) NationalClimaticDataCenter Editor:StephenDelGreco AssistantEditor:StuartHinson STORMDATAisprepared,funded,anddistributedbytheNationalOceanicandAtmosphericAdministration(NOAA).The OutstandingStormsoftheMonthsectionispreparedbytheDataOperationsBranchoftheNationalClimaticDataCenter. TheStormDataandUnusualWeatherPhenomenanarrativesandHurricane/TropicalStormsummariesarepreparedbytheNational WeatherService.Monthlyandannualstatisticsandsummariesoftornadoandlightningeventsresultingindeaths,injuries,anddamage arecompiledbycooperativeeffortsbetweentheNationalClimaticDataCenterandtheStormPredictionCenter. STORMDATAcontainsallconfirmedinformationonstormsavailabletoourstaffatthetimeofpublication.However,dueto difficultiesinherentinthecollectionofthistypeofdata,itisnotall-inclusive.Latereportsandcorrectionsareprintedineachedition. MapsoftheNationalWeatherServiceCountyWarningAreaswhichareusedintheStormDataandUnusualWeatherPhenomena sectionwillbeprintedinalleditions. Exceptforlimitededitingtocorrectgrammaticalerrors,materialssubmittedaregenerallypublishedasreceived. Note:"NoneReported"meansthatnosevereweatheroccurredand"NotReceived"meansthatnoreportswerereceivedforthisregion atthetimeofprinting. 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ActingDirector, NationalClimaticDataCenter 2 May 1997 Confirmed Tornadoes 4 F Scale F0 F1 F2 F3 F4 F5 F Scale F0 F1 F2 F3 F4 F5 Total Num ber 153 39 10 2 1 1 207 OUTSTANDING STORMS OF THE MONTH JARRELL, TEXAS IS DEVASTATED BY F5 TORNADO On May 27th, an F5 tornado was spawned by a supercell thunderstorm which developed along the dryline in central Texas. Morning upper air soundings indicated thermodynamic conditions were favorable for the development of severe weather. The thunderstorm grew rapidly in intensity and size during the early afternoon. The Storm Prediction Center posted a tornado watch at 11:54AM CST (12:54PM CDT). A tornado warning was issued by the National Weather Service (NWS) Office in New Braunfels, TX at 2:30PM CST (3:30PM CDT). The F5 tornado touched down at approximately 2:40 PM CST and entered the Double Creek Estates subdivision near Jarrell, TX at 2:48PM CST. Six tornadoes swept through Williamson and Travis Counties causing 29 fatalities and damage estimated over $125 Million. Even though the upper level winds were moving from southwest to northeast, the tornadic thunderstorms developed in a south-southwest direction, due to a back-building formation of new cells along the dryline. Other reports of severe weather included four inch hail in Cedar Park and Kelly Air Force Base recorded a 122 mph wind gust. Other incredible phenomena include: The F5 tornado completely removed the pavement from the roads it crossed. Three hundred head of cattle were killed, a few were found as far away as a quarter mile. Left: A photograph of the tornado at approximately 2:40PM CST. The funnel dropped out of the wall cloud and touched down 3.5 miles north of Jarrell, TX and moved south-southwest. (Photo courtesy of Charlotte Vancil, Jarrell, TX) Right: A photograph of the above tornado taken by a different photographer approximately 5 minutes later as it approached the Double Creek Estates subdivision on the outskirts of Jarrell. Note the multiple vortices. (Photo courtesy of Scott Beckwith, Jarrell Farm Supply, Jarrell, TX) 5 Left: An aerial view of the tornado path and the remnants of the Double Creek estates. The tornado completely removed the homes from their foundations. (Note the cement slab foundations and the absence of debris) The dark lines in the photo are tire tracks of rescue vehicles as they drove through the fields looking for survivors. (Photo courtesy of Troy Kimmel, KimCo Meteorological Services, Austin, TX) Right: Another aerial view near Jarrell. The powerful F5 tornado scoured the ground in its path. The driveway in this photo led to a house which stood directly in the tornado’s path. (Photo courtesy of Troy Kimmel, KimCo Meteorological Services, Austin, TX) Left: One of the many foundations left by the tornado. Most of the homes in this area were fabricated on cement slabs similar to this one. All of the homes were completely demolished and debris was scattered for miles. Few homes had a basement or storm shelter of any type. (Photo courtesy of Larry Eblen, Jeff Orrock and Bruce Thoren, NWS, Austin/San Antonio, TX) 6 This house located in Cedar Park, TX was heavily This house, also located in Cedar Park, was damaged by airborne debris and tornadic winds. severely damaged. The tornado passed within close proximity to this house. (Photo courtesy of NWS, Austin/San Antonio, TX) (Photo courtesy of NWS, Austin/San Antonio, TX) The remnants of a mobile home and a trailer This vehicle, one of many destroyed by the located at the Double Creek Estates. Note the tornado, is located next to the remnants of a home. absence of large debris. (Photo courtesy of NWS, Austin/San Antonio, TX) (Photo courtesy of NWS, Austin/San Antonio, TX) An aerial view of the Buttercup Creek section of An aerial view of a collapsed roof of a store in Cedar Park depicts how a tornado can destroy a Cedar Park, just north of Austin, TX. home and leave neighbors homes untouched. (Photo courtesy of Troy Kimmel, KimCo , Austin, (Photo courtesy of Troy Kimmel, KimCo, Austin, TX) TX) 7 Right: The parent cloud that produced the Jarrell F5 tornado began as a small thunderstorm at the intersection of two cloud lines in East-Central Texas about 10:00AM CST. The thunderstorms developed southwest along a strong “dryline” and by the time (1:02PM CST) of the GOES-8 Visible Image (right), the primary cell was well established . Left: By 2:45PM CST, the primary cell was showing a distinctive “overshooting top” near the southwest edge (center of photo) of the anvil cloud, while below, the Jarrell F5 tornado was already on the ground. The Doppler radar indicated a maximum cell height of 58,000 feet at 2:35PM CST. Note also the “wake effect” in the cloud top as strong SW to NE winds aloft were forced to flow around the “overshooting top”. Right: By 4:02PM CST, the primary cell had continued to develop southwest and was about to merge into the cirrus “anvil” cloud shield that was streaming northeast from a cell complex that developed near the Texas-Mexico border. (Satellite images courtesy of the National Climatic Data Center) 8 Storm Data and Unusual Weather Phenomena Time Path Path Number of Estimated May 1997 Local/ Length Width Persons Damage Location Date Standard (Miles) (Yards) Killed Injured Property Crops Character of Storm ALABAMA, North Central Marion County Hamilton 02 1515CST 0 0 5K 0 Thunderstorm Wind (G50) Trees were reported down in Hamilton. Lamar County 10 N Vernon 02 1520CST 0 0 6K 0 Thunderstorm Wind (G50) Trees and a few power lines were reported down between Sulligent and Vernon. Time estimated. Colbert County Muscle Shoals 02 1526CST 0 0 5K 0 Thunderstorm Wind (G56) A gust to 64 mph was recorded by the ASOS at the Muscle Shoals Airport. Winston County Double Spgs 02 1605CST 0 0 6K 0 Tstm Wind/Hail Trees were down in Double Springs, and dime size hail was reported in many locations in the western part of the county. Walker County Eldridge 02 1630CST 0 0 3K 0 Hail (0.75) Dime size hail was reported in Eldridge, in the northwest part of the county. Cullman County 3 W West Pt 02 1652CST 0 0 3K 0 Hail (0.75) Dime size hail was reported in the northwest part of the county. Morgan County Decatur 02 1700CST 0 0 6K 0 Thunderstorm Wind (G50) Several trees were uprooted in Decatur and Hartselle. There were also some power outages due to trees falling on the lines. Marion County Guin 02 1705CST 0 0 5K 0 Thunderstorm Wind (G50) Trees were down near Guin in the southwest part of the county, in the southern part of the county, reported by the EMA. Winston County Haleyville 02 1740CST 0 0 4K 0 Hail (0.88) Nickel size