Alert archive / West Virginia / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 29, NWS Baltimore/Washington

April 8, 2020Frederick County, Virginia; Allegany County, Washington County, Maryland; 4 counties in West Virginia

NWS Baltimore/Washington issued this severe thunderstorm warning at Apr 8, 2020, 2:50 AM EDT for Frederick County, Virginia; Allegany County, Washington County, Maryland; 4 counties in West Virginia. It was in force for 55 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Apr 8, 2020, 2:50 AM EDT (06:50 UTC)
Expired: Apr 8, 2020, 3:45 AM EDT
In force: 55 min
Issued by: NWS Baltimore/Washington
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Allegany County, MD, Washington County, MD, Frederick County, VA, Berkeley County, WV, Hampshire County, WV, Jefferson County, WV, Morgan County, WV

The radar

The Sterling radar (KLWX), 81 km from the middle of the area, began a volume at 06:51 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Apr 8, 2:14 AM EDT	Severe Thunderstorm Watch	SPC	2 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 6.8 hours before the alert went out and 89 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 14 J/kg
Mixed-layer CIN: -214 J/kg
Mixed-layer LCL: 1167 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 76 m²/s²
0-3 km storm-relative helicity: 118 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Baltimore/Washington wrote its last area forecast discussion before this severe thunderstorm warning went out at Apr 7, 9:45 PM EDT, 5 hours 5 minutes earlier.

Area forecast discussion, Apr 7, 9:45 PM EDT, 5 hours 5 minutes before

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Hazardous weather outlook, Apr 8, 2:19 AM EDT, 31 minutes before

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In the hours before

Local storm report, Apr 7, 11:38 PM EDT, 3 hours 12 minutes before

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Local storm report, Apr 7, 11:40 PM EDT, 3 hours 10 minutes before

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Local storm report, Apr 7, 11:57 PM EDT, 2 hours 53 minutes before

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The office that day

Everything else NWS Baltimore/Washington issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 7, 8:43 PM EDT	Severe Thunderstorm Warning	LWX	Highland	62 min
Apr 7, 9:54 PM EDT	Severe Thunderstorm Warning	LWX	Augusta	51 min
Apr 7, 10:21 PM EDT	Severe Thunderstorm Warning	LWX	Augusta, Nelson	54 min
Apr 7, 11:47 PM EDT	Special Marine Warning	LWX		58 min
Apr 8, 12:56 AM EDT	Special Marine Warning	LWX		30 min
Apr 8, 2:20 AM EDT	Small Craft Advisory	LWX		18 hr
Apr 8, 3:43 AM EDT	Severe Thunderstorm Warning	LWX	Clarke, Frederick, Loudoun	47 min
Apr 8, 3:51 AM EDT	Special Marine Warning	LWX		73 min
Apr 8, 3:58 AM EDT	Special Marine Warning	LWX		49 min
Apr 8, 4:20 AM EDT	Special Marine Warning	LWX		85 min
Apr 8, 4:22 AM EDT	Severe Thunderstorm Warning	LWX	Arlington, Fairfax, City of Alexandria, City of Falls Church	38 min
Apr 8, 4:40 AM EDT	Special Marine Warning	LWX		56 min
Apr 8, 4:57 AM EDT	Special Marine Warning	LWX		93 min
Apr 8, 5:03 AM EDT	Severe Thunderstorm Warning	LWX	Highland	42 min
Apr 8, 5:32 AM EDT	Severe Thunderstorm Warning	LWX	Augusta, City of Staunton, City of Waynesboro	43 min
Apr 8, 6:00 AM EDT	Severe Thunderstorm Warning	LWX	Albemarle, Nelson	45 min
Apr 8, 2:46 PM EDT	Gale Warning	LWX		29 hr
Apr 8, 2:46 PM EDT	Small Craft Advisory	LWX		42 hr
Apr 8, 12:52 AM EDT	Severe Thunderstorm Warning	LWX	Harford	24 min
Apr 8, 2:29 AM EDT	Severe Thunderstorm Warning	LWX	Allegany	61 min
Apr 8, 3:53 AM EDT	Severe Thunderstorm Warning	LWX	Anne Arundel, Baltimore, Carroll, Frederick, Harford, Howard and 1 more	37 min

Nearby

Severe Thunderstorm Warnings in West Virginia, 2020 Severe Thunderstorm Warnings in Maryland, 2020 Severe Thunderstorm Warnings in Virginia, 2020 Every severe thunderstorm warning in 2020

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.