Alert archive / Virginia / Severe Thunderstorm Watches in 1997

Severe Thunderstorm Watch 699

August 17, 19974 states

The Storm Prediction Center issued this severe thunderstorm watch at Aug 17, 1997, 4:30 PM EDT for 4 states. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Aug 17, 1997, 4:30 PM EDT (20:30 UTC)
Expired
Aug 17, 1997, 11:00 PM EDT
In force
7 hr
Issued by
the Storm Prediction Center
All 66 counties

Allegany County, MD, Baltimore County, MD, Carroll County, MD, City of Baltimore, MD, Frederick County, MD, Garrett County, MD, Howard County, MD, Montgomery County, MD, Washington County, MD, Adams County, PA, Bedford County, PA, Cumberland County, PA, Franklin County, PA, Fulton County, PA, Lancaster County, PA, Lebanon County, PA, Somerset County, PA, York County, PA, Albemarle County, VA, Arlington County, VA, Augusta County, VA, Bath County, VA, City of Alexandria, VA, City of Charlottesville, VA, City of Fairfax, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Harrisonburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Staunton, VA, City of Waynesboro, VA, City of Winchester, VA, Clarke County, VA, Culpeper County, VA, Fairfax County, VA, Fauquier County, VA, Frederick County, VA, Greene County, VA, Highland County, VA, Loudoun County, VA, Louisa County, VA, Madison County, VA, Orange County, VA, Page County, VA, Prince William County, VA, Rappahannock County, VA, Rockingham County, VA, Shenandoah County, VA, Spotsylvania County, VA, Stafford County, VA, Warren County, VA, Barbour County, WV, Berkeley County, WV, Grant County, WV, Hampshire County, WV, Hardy County, WV, Jefferson County, WV, Mineral County, WV, Morgan County, WV, Pendleton County, WV, Pocahontas County, WV, Preston County, WV, Randolph County, WV, Tucker County, WV, Webster County, WV

The radar

The Sterling radar (KLWX), 119 km from the middle of the area, began a volume at 20:35 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

Warnings issued inside it

20 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Aug 17, 4:45 PM EDTSevere Thunderstorm WarningCTPBedford, Somerset60 min
Aug 17, 4:46 PM EDTSevere Thunderstorm WarningLWXMineral34 min
Aug 17, 4:55 PM EDTSevere Thunderstorm WarningLWXHampshire45 min
Aug 17, 4:57 PM EDTSevere Thunderstorm WarningRLXWebster63 min
Aug 17, 5:12 PM EDTSevere Thunderstorm WarningCTPFulton58 min
Aug 17, 5:17 PM EDTSevere Thunderstorm WarningLWXFrederick48 min
Aug 17, 5:17 PM EDTSevere Thunderstorm WarningRLXRandolph, Upshur58 min
Aug 17, 5:25 PM EDTSevere Thunderstorm WarningLWXHoward, Montgomery35 min
Aug 17, 5:25 PM EDTTornado WarningCTPBedford, Fulton35 min
Aug 17, 5:29 PM EDTSevere Thunderstorm WarningLWXFairfax46 min
Aug 17, 5:40 PM EDTTornado WarningCTPFranklin50 min
Aug 17, 5:50 PM EDTSevere Thunderstorm WarningLWXWashington50 min
Aug 17, 6:06 PM EDTSevere Thunderstorm WarningLWXArlington49 min
Aug 17, 6:43 PM EDTSevere Thunderstorm WarningLWXFrederick47 min
Aug 17, 6:53 PM EDTSevere Thunderstorm WarningLWXHoward, Montgomery47 min
Aug 17, 6:59 PM EDTSevere Thunderstorm WarningLWXFairfax, Prince William46 min
Aug 17, 7:10 PM EDTSevere Thunderstorm WarningLWXCarroll50 min
Aug 17, 7:34 PM EDTSevere Thunderstorm WarningLWXBaltimore, City of Baltimore46 min
Aug 17, 7:45 PM EDTSevere Thunderstorm WarningLWXAnne Arundel, Howard30 min
Aug 17, 8:12 PM EDTSevere Thunderstorm WarningLWXFauquier33 min

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 8.5 hours before the alert went out and 126 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 1997-08-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 129 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 1997-08-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -40 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
129 J/kg
Mixed-layer CIN
-282 J/kg
Mixed-layer LCL
1590 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
-40 m²/s²
0-3 km storm-relative helicity
37 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 17, 6:00 PM EDTSevere Thunderstorm WatchSPCAnne Arundel, Calvert, Caroline, Cecil, Charles, Dorchester and 9 more6 hr
Aug 17, 1:15 PM EDTSevere Thunderstorm WatchSPCBarbour, Boone, Braxton, Cabell, Calhoun, Clay and 29 more7 hr

Nearby

Severe Thunderstorm Watches in Virginia, 1997Severe Thunderstorm Watches in West Virginia, 1997Severe Thunderstorm Watches in Maryland, 1997Every severe thunderstorm watch in 1997

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.