The High Wind Event of 7 March 2004 in the Piedmont of the Western Carolinas

Harry GerapetritisNational Weather ServiceGreer, SC

High Impact EventSteeple blown off church in Hickory, NCWidespread grass firesBarns and mobile homes blown over in Gastonia, NC and an historic church moved off its foundationLarge limbs crashing through roofs in Salisbury, NCOver 30,000 people without power in Charlotte metro areaControl tower evacuated at Charlotte-Douglas International Airport due to wind gusts of 55 mphHuntersville, NC man killed by a falling tree limb, and a thirteen year-old boy drowned on Lake Greenwood, SC

Magnitude of Event Largely UnanticipatedFoothills:.TONIGHTPARTLY CLOUDY WITH A CHANCE OF RAIN SHOWERS THIS EVENING. VERY WINDY WITH LOWS IN THE MID 30S. NORTHWEST WINDS 20 TO 30 MPHWITH GUSTS NEAR 50 MPH AT THE HIGHER ELEVATIONS. CHANCE OF PRECIPITATION 40 PERCENT.Piedmont:.TONIGHTPARTLY CLOUDY WITH A 30 PERCENT CHANCE OF RAIN SHOWERS THIS EVENING. WINDY WITH LOWS IN THE MID 30S. WEST WINDS 15 TO 25 MPH.FOUS22 KHKY 071200KHKY GFS MOS GUIDANCE 3/07/2004 1200 UTCDT /MAR 7/MAR 8 /MAR 9 /MAR 10HR 18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 06 12N/X 38 55 32 45 27TMP 66 66 58 51 47 44 40 49 51 52 46 40 37 35 34 40 42 43 40 31 29DPT 40 36 33 31 27 24 23 24 24 23 22 22 24 23 23 24 26 26 26 24 22CLD SC SC OV CL CL CL CL CL SC SC CL CL SC SC OV OV OV OV OV OV SCWDR 25 27 30 31 30 30 30 32 32 32 32 32 32 32 33 00 10 05 03 36 35WSP 09 12 15 15 15 14 12 16 15 13 10 07 06 04 01 00 01 01 03 07 07P06 27 16 8 4 1 1 3 17 52 27 15P12 18 4 3 52 31

500 hPa Eta Forecast at 00 UTC March 8, 2004500 hPa heights, wind barbs, isotachs

850 hPa Eta Forecast for 12 UTC March 8, 2004850 hPa heights, winds, isotachs

Visible Imagery and Surface Observations 20 UTC

00 UTC March 8, 2004 Greensboro, NC Sounding (GSO)

KGSP Composite Reflectivity 0100 UTC 8 March 2004

Eta Frontogenesis Forecast at 00 UTC 8 March, 2004850 hPa 2-D Fn, MSLP, 1000-850 thickness

Eta Cross Section Valid at 00 UTC 8 March 2004Potential temperature, omega, wind barbs

00 UTC 5 February 2002 Blacksburg, VA Sounding (RNK)

500 hPa Eta Forecast valid at 00 UTC 5 February 2002500 hPa heights, wind barbs, isotachs

Eta Cross Section valid at 00 UTC 5 February 2002Potential temperature, omega, wind barbs

00 UTC 29 March 2000 Greensboro, NC Sounding (GSO)

Eta 500 hPa Forecast valid at 00 UTC 29 March 2000500 hPa heights, wind barbs, isotachs

Eta Cross Section valid at 00 UTC 29 March 2000Potential temperature, omega, wind barbs

Summary

Consider high wind potential if you have:A deep, surface-based, mixed layerDry-adiabatic into the 800-700 hPa layer, or higherUsually capped by a narrow moist zone with dewpoint depressions 5 degrees C or lessA strong, mid-tropospheric speed maximumWinds 50 knots or greater at 700 hPa, or top of mixed layerWinds 100 knots or greater at 500 hPaStrong downward omega in the lower troposphere6 to 9 microbars/second or strongerSubsidence is often due to cold advection, but frontogenesis or other sources can also contribute