Overview
A strong storm system led to several rounds of strong to severe storms across the forecast area and the eastern U.S. as a whole. Widespread damaging winds were the most common occurrence locally, but the event also produced more than a dozen hail reports of quarter to in excess of golf ball size, a fairly uncommon event in our region.Wind & Hail
Nearly 50 reports of wind and hail were received on the day of the event with the wind reports being most widespread. Over one dozen reports of hail were received with sizes ranging from 1" to nearly 2".
Wind
Observational Data from the Automated Station at the Knoxville McGhee Tyson Airport Showing Wind Gusts in Excess of 60 mph |
German Creek Marina, Bean Station, TN (Courtesy Trained Spotter) | Downed Tree in Greeneville (Courtesy Christopher Starnes) | Dorsey Street on Chattanooga's Southside (Courtesy Viewer Photo to WTVC-TV) | Lenoir City (Courtesy Josh Marler) |
Hail
Golf Ball to Lime Sized Hail (1.75" to 2") in Loudon County (Courtesy Tim and Kelly Cutshaw) | Golf Ball to Lime Sized Hail (1.75" to 2") in Loudon County (Courtesy Tim and Kelly Cutshaw) | Hail to 1" or More in Diameter in Chestnut Hill, TN |
Radar
KMRX Radar of Reflectivity (left) and Velocity (right) at 2130 UTC (530 PM ET) across Grainger County, Near the Time of Damage at the German Creek Marina | KMRX Radar of Reflectivity (left) and Velocity (right) at 2028 UTC (428 PM ET) centered across the McGhee Tyson Airport, Knoxville |
KMRX Radar of Reflectivity (top left), Velocity (top right), Maximum Estimated Hail (MESH), and Correlation Coefficient at 2130 UTC (530 PM ET) across Loudon County. MESH estimated 2+ inch hail | Cross-Section from KMRX radar at 2130 UTC (530 PM ET) across Loudon County. High reflectivity core near 30kft+ above the ground. |
Storm Reports
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON... ..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE.... ..REMARKS.. 0712 PM TSTM WND DMG 1 WSW HILANDER PARK 36.77N 82.10W 05/06/2022 WASHINGTON VA PUBLIC A FEW TREES DOWN. 0700 PM TSTM WND DMG 3 SSW HARR 36.54N 82.01W 05/06/2022 SULLIVAN TN PUBLIC SOME TREES AND POWER LINES DOWN. 0640 PM TSTM WND DMG 5 S COLLINGWOOD 36.67N 82.32W 05/06/2022 WASHINGTON VA PUBLIC SEVERAL TREES DOWN. 0625 PM TSTM WND DMG 1 NNE JOHNSON CITY 36.35N 82.35W 05/06/2022 WASHINGTON TN LAW ENFORCEMENT TREES AND POWER LINES DOWN ACROSS THE ENTIRE COUNTY. 0612 PM TSTM WND DMG 1 WNW CHURCH HILL 36.53N 82.73W 05/06/2022 HAWKINS TN TRAINED SPOTTER TWO TREES BLOWN DOWN AND 58 MPH WIND GUST RECORDED ON HOME WEATHER STATION. 0612 PM HAIL 1 WNW CHURCH HILL 36.53N 82.73W 05/06/2022 M1.00 INCH HAWKINS TN TRAINED SPOTTER QUARTER SIZE HAIL REPORTED. 0608 PM TSTM WND DMG 2 SW ROGERSVILLE 36.39N 83.03W 05/06/2022 HAWKINS TN LAW ENFORCEMENT TREES AND POWER LINES DOWN SEVERAL LOCATIONS ACROSS THE COUNTY. 0604 PM TSTM WND DMG 6 NNE TAZEWELL 36.53N 83.53W 05/06/2022 CLAIBORNE TN PUBLIC SEVERAL TREES AND POWER LINES DOWN. 0542 PM HAIL 1 S GREENEVILLE 36.16N 82.82W 05/06/2022 E1.00 INCH GREENE TN PUBLIC QUARTER SIZE HAIL REPORTED 1 MILE SOUTH OF GREENVILLE. 0510 PM HAIL 3 SE BLOOMINGDALE 36.54N 82.46W 05/06/2022 E1.25 INCH SULLIVAN TN PUBLIC 0505 PM TSTM WND DMG LUTTRELL 36.21N 83.75W 05/06/2022 UNION TN LAW ENFORCEMENT TREES AND POWER LINES DOWN. 0505 PM TSTM WND DMG SHARPS CHAPEL 36.34N 83.81W 05/06/2022 UNION TN LAW ENFORCEMENT TREES AND POWER LINES DOWN. 0505 PM TSTM WND DMG MAYNARDVILLE 36.25N 83.81W 05/06/2022 UNION TN LAW ENFORCEMENT TREES AND POWER LINES DOWN. 0505 PM HAIL CHESTNUT HILL 35.93N 83.34W 05/06/2022 M1.00 INCH JEFFERSON TN PUBLIC 0455 PM HAIL 2 ESE BENHAMS 36.66N 82.18W 05/06/2022 E1.25 INCH WASHINGTON VA LAW ENFORCEMENT SEVERAL TREES AND POWER LINES DOWN AS WELL. 0448 PM HAIL 3 NNW GREENEVILLE 36.20N 82.84W 05/06/2022 E1.25 INCH GREENE TN PUBLIC 0430 PM TSTM WND DMG 2 NNW PIGEON FORGE 35.82N 83.58W 05/06/2022 SEVIER TN EMERGENCY MNGR TREES AND POWER LINES DOWN BETWEEN PIGEON FORGE AND SEVIERVILLE. 0330 PM HAIL 1 NNW PIONEER 36.44N 84.32W 05/06/2022 E1.25 INCH CAMPBELL TN PUBLIC CORRECTS PREVIOUS HAIL REPORT FROM 1 NNW PIONEER. TREES AND POWER LINES DOWN. 0250 PM HAIL 1 WNW TARIFFVILLE 35.49N 84.19W 05/06/2022 E1.50 INCH MONROE TN PUBLIC SEVERAL TREES DOWN. 0214 PM TSTM WND DMG 1 NE WHITWELL 35.21N 85.51W 05/06/2022 MARION TN LAW ENFORCEMENT A FEW TREES DOWN.
Environment
A strong upper trough moved across the midsection of the Ohio and Tennessee Valleys into the central and southern Appalachians from mid-afternoon through early Friday evening. The strongest part of the jet was over the southern Appalachians where 300mb winds exceeded 90 knots. This placed East Tennessee, southwest Virginia, and southwest North Carolina under strong upper forcing during the afternoon and evening of Friday, May 6th 2022.
A thermal trough of colder air pulled eastward into the southern Appalachians late Friday. The 500mb temperature map depicted temperatures dropping below -16 degrees Celsius. The colder air helped to increase the instability over the area as well as enhanced the potential for large hail.
The strong upper jet structure produced a relatively deep trough of low pressure system over the Ohio and Tennessee Valleys. This deep low pressure system strengthened the boundary layer jet over the southern Appalachians and southeast United States pulling abundant moisture and instability into the region.
Figure 1: 300mb Heights, Divergence, and Winds at 2300 UTC, 06 May 2022 | Figure 2: 500mb Heights, Winds, and Temperatures at 2000 UTC, 6 May 2022 | Figure 3: 850mb Heights, Temperatures, and Winds at 2000 UTC, 6 May 2022 |
The strong low-level jet pulled abundant moisture into the East Tennessee Valley and the southern Appalachian region. Unseasonably warm air was also pulled north into East Tennessee, southwest Virginia, and southwest North Carolina with temperatures climbing into the 70s over much of the area. The increased moisture and unseasonably warm temperatures produced an unstable air-mass over the Tennessee Valley and southern Appalachians.
Figure 4: 850mb Moisture Transport at 1800 UTC, 6 May 2022 | Figure 5: Surface Temperature, Dewpoints, Winds, and Isobars at 1800 UTC, 6 May 2022 | Figure 6: Surface Station Plot at 1900 UTC, 6 May 2022 |
Figure 7: Surface Analysis of Isobars, Temperatures, Dewpoints, Fronts, and Low Pressure Centers at 1900 UTC, 6 May 2022 | Figure 8: MLCAPE and CIN at 2000 UTC, 6 May 2022 | Figure 9: Mid-Level Lapse Rates (700-500mb) at 1900 UTC, 6 May 2022 |
Numerous storms produced large hail of 1 inch or greater with several reports up to golf ball size. The main contributors to the numerous hail was the cold air aloft and the sustained updrafts with the storms. The cold air produced high mid-level lapse rates and favorable values of Hail CAPE. The Significant Hail Parameter (SHIP) depicted values of 1 or greater across much of the area, which indicated the potential of large hail.
Figure 10: Hail CAPE (-10 to -30 Celsius) at 2000 UTC, 6 May 2022 | Figure 11: Significant Hail Parameter (SHIP) at 2000 UTC, 6 May 2022 | Figure 12: 0-1km Shear at 2000 UTC, 6 May 2022 |
Several of the storms late Friday exhibited mid-level and low-level rotation, but no confirmed tornadoes were reported. Effective and 0-1km shear were favorable for tornado development, but speed shear contributed to most of the available shear. The more favorable low-level environments occur with some directional shear when the low-level winds are southerly. The lack of low-level directional shear limited the Significant Tornado Parameter due the event.
Figure 13: Effective Shear at 2000 UTC, 6 May 2022 | Figure 14: Supercell Composite Parameter (SCP) at 2000 UTC, 6 May 2022 | Figure 15: Significant Tornado Parameter (STP) at 2000 UTC, 6 May 2022 |
The main severe weather threat from the line of showers and thunderstorms were damaging straight-line winds. The main reason why these storms produced high winds was due to the availability of mid-level dry air and the strong pressure rises behind the frontal boundary. The Derecho Composite Parameter depicted values between 2 and 4 across much of the area. Typically, values of 2 or greater indicate an environment favorable for damaging winds.
Figure 16: 2 Hour Surface Pressure Change at 2100 UTC, 6 May 2022 | Figure 17: Derecho Composite Parameter (DCP) at 2000 UTC, 6 May 2022 |
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