July 2001 Severe Weather Events



July 4 - Squall Line    July 8 - Squall Line    July 25-29 - Flooding



July 4th

An upper level disturbance swept through the Ohio and Tennessee Valleys during the afternoon on July 4th. By late morning, there were 3 lines of storms: one extending from southeast Kentucky into the northern Cumberland Plateau, the second over central southern Kentucky, and the third was a small line over northern middle Tennessee. These eventually merged into one large line over the Morristown County Warning Area (CWA). You can view these line merges through two radar loops. The Morristown radar loop (1.03 MB) which runs from 1:03 p.m. EDT to 6:23 p.m., or the Hytop radar loop (691 KB) which runs from 4:00 p.m. EDT to 7:43 p.m. Data indicated that instability was high with CAPEs from 2000-3000 J/kg and lifted indices of -6 to -8. The National Weather Service in Morristown (MRX) issued severe thunderstorm warnings for 36 out of the 40 counties in the CWA during the event. Thirty-three of these thirty-six warnings verified with severe weather events (thunderstorm winds of 58 mph or greater, or hail 3/4 of an inch in diameter). All of the damage that was reported to the NWS MRX was either trees or power lines downed from severe winds.


July 8th

A dissipating Mesoscale Convective System (MCS) sent an outflow boundary across the Ohio Valley. This initiated new thunderstorm development in the early afternoon. The atmosphere was very unstable with CAPEs exceeding 4000 J/kg over the MRX CWA. The low and mid level winds were very strong, especially for July, with up to 80 knots at 7000 feet in Kentucky estimated by the Jackson, Kentucky radar. The thunderstorms that developed across the Ohio Valley organized into a squall line over northern Kentucky and moved south-southeast. As this line moved into southwest Virginia, addition storms fired near the Tri-Cities region in northeast Tennessee. These additional storms helped to sustain the line as it was beginning to weaken along the Virginia/Tennessee border. This evolution can be seen on the MRX radar loop (822KB). Twenty-two severe thunderstorm warnings were issued, mainly for southwest Virginia and northeast Tennessee. Twenty out of these twenty-two warnings were verified with severe weather events. Severe reports included widespread trees and power lines downed, a couple of roofs damaged in the Tri-Cities region, a couple of reports of dime size hail (3/4 inch in diameter), and urban and small stream flooding.


July 25th through 29th

On July 26th and 27th numerous showers and thunderstorms moved from southeast Kentucky into southwest Virginia and northeast Tennessee. Rainfall amounts from these two days ranged from just a few tenths of an inch up to 5 inches. This area of heavier rainfall can been seen in the radar estimation of rainfall for the 48 hours (2 days) ending 6 a.m. EDT July 28th. While this rainfall did cause some minor urban and small stream flooding, for the most part the rainfall just saturated the ground and set the conditions that would lead to widespread flooding during the next two days.

Rainfall picked up again in the evening hours on July 28th across southwest Virginia and northeast Tennessee. The composite radar loop (1.5 MB) shows the numerous showers and thunderstorms that moved through the region from 8 p.m. on July 27 to 2 p.m. on July 29. The flash flood watch was issued on July 28th at 11:15 a.m., and the first flash flood warning was issued at 2:15 a.m. on July 29th. Thirty-two subsequent flash flood warnings were issued across southwest Virginia and northeast Tennessee through the rest of the day on the 29th. Rainfall amounts for July 28th and 29th were similar to those on the two previous days as indicated by the 2 day radar estimation of rainfall ending 6 a.m. EDT July 30th. The difference this time was the ground was already saturated and nearly all of the rain that fell on July 28th and 29th became runoff. The table below gives readings from rain gauges that are part of the Integrated Flood Observing and Warning System (IFLOWS), from July 25th through July 29th.

County, State
Location
July 25
July 26
July 27
July 28
July 29
Total
Scott, VA
Camp Rock
0.12
0.48
1.36
0.44
4.08
6.48
Scott, VA
Maple Gap
0.44
0.40
1.52
0.72
4.59
7.67
Scott, VA
Purchase Ridge
0.20
0.04
0.88
1.92
2.18
5.22
Scott, VA
Little Duck
0.12
0
0.16
0.60
0.16
1.04
Scott, VA
Gate City
0.87
0.04
0.68
1.48
2.00
5.07
Wise, VA
Pound Gap
0
2.78
0
0.44
0.52
3.74
Wise, VA
Indian Gap
0
0.56
1.14
0.32
1.64
3.66
Wise, VA
Sandy Ridge
0.16
0.24
1.08
0.20
2.12
3.80
Wise, VA
Roda
0
0.32
0.20
0.52
1.80
2.84
Wise, VA
Black Mtn
0.28
0.60
0.40
0.96
4.86
7.10
Wise, VA
Powell Mtn
0.40
0.24
0.56
0.72
1.88
3.80
Wise, VA
Divide Ridge
0
0.52
0.56
0.36
1.20
2.64
Wise, VA
Robinson Knob
0.83
0.68
1.36
0.48
1.32
4.67
Wise, VA
Fox Gap
0.32
0.84
0.08
0.36
1.48
3.08
Wise, VA
Hall Hollow
0
1.19
1.44
0.72
5.50
8.85
Wise, VA
Big Cherry Dam
0.52
0.16
0.32
0.12
0.08
1.20
Lee, VA
Robbins Chapel
0.28
0.92
0.67
0.96
2.19
5.02
Lee, VA
Benedict
0.08
0.28
0.32
0.20
0.12
1.00
Lee, VA
Bonny Blue
0.08
0.68
0.52
1.31
0.96
3.55
Lee, VA
Puckett Creek
0.08
0.32
0.64
1.44
1.24
3.72
Lee, VA
Stickleyville
1.38
0.28
1.19
0.92
4.46
8.23
Washington, VA
Whitetop Mtn
0.68
0.64
0.52
1.44
2.08
5.36
Washington, VA
Black Hollow
0.20
0.24
0.36
1.04
2.44
4.28
Washington, VA
Bristol
0.64
0.04
0.16
1.12
0.68
2.64
Washington, VA
Shady Valley
1.47
0.52
0.76
1.20
1.84
5.79
Washington, VA
Willis
0.87
0.48
0.48
1.84
3.16
6.83
Washington, VA
Damascus
0.84
0.44
0.36
0.96
1.80
4.40
Russell, VA
Pistol Gap
0.12
3.36
0.24
0.44
2.67
6.83
Russell, VA
Drill
0.16
5.95
0.80
0.72
4.66
12.29
Russell, VA
Belfast
0.44
1.48
0.64
0.84
1.64
5.04
Johnson, TN
Heath
1.20
1.28
0.56
2.20
4.97
10.21
Johnson, TN
Trade
1.24
1.16
1.20
1.52
0.52
5.64
Sullivan, TN
Blountville
1.03
0.04
0.80
2.36
1.28
5.51
Sullivan, TN
Fordtown
0.04
0
0.76
1.56
1.08
3.44
Sullivan, TN
Bays Mtn
1.15
0
0.84
2.55
1.84
6.38
Sullivan, TN
Bristol Speedway
0.60
0.04
0.32
1.68
0.68
3.32
Carter, TN
Holston
1.07
0.08
0.80
0.68
0.72
3.35
Carter, TN
Buladeen
0.36
0.24
0.68
1.92
2.43
5.63
Carter, TN
Roan Mtn
0.04
0.63
0.44
0.48
1.12
2.71
Carter, TN
Ripshin Lake
0.64
0.71
0.52
0.52
2.24
4.63
Carter, TN
Roan Mtn St Pk
0.04
0.36
0.48
0.28
1.04
2.20
Carter, TN
Hampton VFD
0.24
0.08
1.96
0.80
1.44
4.52
Carter, TN
Dennis Cove
0.16
0.24
1.60
1.00
1.64
4.64
Hawkins, TN
High Spur TN Twr
1.08
0
0.28
1.46
1.20
4.02
Hawkins, TN
Stanley Valley
1.66
0
0.32
1.36
0.44
3.78
County, State
Location
July 25
July 26
July 27
July 28
July 29
Total


Unfortunately, one man died in Scott County, Virginia, along Big Stoney Creek near Fort Blackmore, when his home was swept away by the flood water. Here are links to three damage photographs in Scott County, Virginia:

View of bridge damage
Bridge damage.

Second view of bridge damage
Second view of bridge damage.

View of house foundation compromised
House foundation compromised.


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