Alert archive / Maryland / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 348, NWS Baltimore/Washington

August 7, 2020Frederick County, Washington County, Maryland; Berkeley County, Jefferson County, West Virginia

NWS Baltimore/Washington issued this severe thunderstorm warning at Aug 7, 2020, 2:08 PM EDT for Frederick County, Washington County, Maryland; Berkeley County, Jefferson County, West Virginia. It was in force for 52 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
Aug 7, 2020, 2:08 PM EDT (18:08 UTC)
Expired
Aug 7, 2020, 3:00 PM EDT
In force
52 min
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Frederick County, MD, Washington County, MD, Berkeley County, WV, Jefferson County, WV

The radar

The Sterling radar (KLWX), 59 km from the middle of the area, began a volume at 18:10 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 nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 6.1 hours before the alert went out and 65 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 2020-08-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 301 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 2020-08-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -37 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
301 J/kg
Mixed-layer CIN
-67 J/kg
Mixed-layer LCL
665 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
-37 m²/s²
0-3 km storm-relative helicity
18 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 Aug 7, 10:12 AM EDT, 3 hours 56 minutes earlier.

Area forecast discussion, Aug 7, 10:12 AM EDT, 3 hours 56 minutes before
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Hazardous weather outlook, Aug 7, 5:12 AM EDT, 8 hours 56 minutes before
Hazardous Weather Outlook
National Weather Service Baltimore MD/Washington DC
512 AM EDT Fri Aug 7 2020

ANZ530>543-DCZ001-MDZ011-013-014-016>018-508-VAZ052>057-080915-
Chesapeake Bay north of Pooles Island MD-
Chesapeake Bay from Pooles Island to Sandy Point MD-
Chesapeake Bay from Sandy Point to North Beach MD-
Chesapeake Bay from North Beach to Drum Point MD-
Chesapeake Bay from Drum Point MD to Smith Point VA-
Tidal Potomac from Key Bridge to Indian Head MD-
Tidal Potomac from Indian Head to Cobb Island MD-
Tidal Potomac from Cobb Island MD to Smith Point VA-
Patapsco River including Baltimore Harbor-
Chester River to Queenstown MD-Eastern Bay-
Choptank River to Cambridge MD and the Little Choptank River-
Patuxent River to Broomes Island MD-
Tangier Sound and the inland waters surrounding Bloodsworth
Island-District of Columbia-Southern Baltimore-Prince Georges-
Anne Arundel-Charles-St. Marys-Calvert-Southeast Harford-
Prince William/Manassas/Manassas Park-Fairfax-
Arlington/Falls Church/Alexandria-Stafford-Spotsylvania-
King George-
512 AM EDT Fri Aug 7 2020

This Hazardous Weather Outlook is for the Maryland portion of the
Chesapeake Bay, Tidal Potomac River, and adjacent counties in
central Maryland and northern Virginia as well as the District of
Columbia.

.DAY ONE...Today and Tonight

A Flash Flood Watch is in effect for the outlook area this
afternoon and tonight.

Isolated severe thunderstorms are also possible this afternoon and
this evening.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Please report any wind damage or flooding to the National Weather
Service.

MDZ003>006-501>507-VAZ025>031-036>040-050-051-501>508-WVZ050>053-
055-501>506-080915-
Washington-Frederick MD-Carroll-Northern Baltimore-
Extreme Western Allegany-Central and Eastern Allegany-
Northwest Montgomery-Central and Southeast Montgomery-
Northwest Howard-Central and Southeast Howard-Northwest Harford-
Augusta-Rockingham-Shenandoah-Frederick VA-Page-Warren-Clarke-
Nelson-Albemarle-Greene-Madison-Rappahannock-Orange-Culpeper-
Northern Fauquier-Southern Fauquier-Western Highland-
Eastern Highland-Western Loudoun-Eastern Loudoun-
Northern Virginia Blue Ridge-Central Virginia Blue Ridge-
Hampshire-Morgan-Berkeley-Jefferson-Hardy-Western Grant-
Eastern Grant-Western Mineral-Eastern Mineral-Western Pendleton-
Eastern Pendleton-
512 AM EDT Fri Aug 7 2020

This Hazardous Weather Outlook is for eastern West Virginia,
northern and central Virginia, and central and western Maryland
with the exception of Garrett County.

.DAY ONE...Today and Tonight

A Flash Flood Watch is in effect for southern and eastern portions
of the outlook area this afternoon and tonight.

Isolated severe thunderstorms are also possible this afternoon and
this evening.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Please report any wind damage or flooding to the National Weather
Service.

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 6, 8:54 PM EDTAreal Flood WarningLWXLoudoun6 hr
Aug 6, 8:56 PM EDTSevere Thunderstorm WarningLWXLoudoun49 min
Aug 6, 9:06 PM EDTFlash Flood Warning Considerable damage threatLWXLoudoun3 hr
Aug 6, 9:34 PM EDTAreal Flood WarningLWXSpotsylvania2 hr
Aug 6, 10:09 PM EDTFlash Flood Warning Considerable damage threatLWXLoudoun4 hr
Aug 6, 10:13 PM EDTFlash Flood Warning EmergencyCatastrophic damage threatLWXLoudoun96 min
Aug 7, 2:04 AM EDTAreal Flood WarningLWXLoudoun3 hr
Aug 7, 2:21 AM EDTAreal Flood WarningLWXLoudoun5 hr
Aug 7, 3:46 AM EDTFlash Flood WatchLWXAlbemarle, Amherst, Arlington, Augusta, Culpeper, Fairfax and 22 more21 hr
Aug 7, 2:33 PM EDTSevere Thunderstorm WarningLWXAugusta, Rockingham42 min
Aug 7, 4:39 PM EDTSevere Thunderstorm WarningLWXAugusta, Rockingham, City of Staunton51 min
Aug 7, 5:13 PM EDTSevere Thunderstorm WarningLWXAugusta, City of Waynesboro47 min
Aug 7, 5:39 PM EDTSpecial Marine WarningLWX2 hr
Aug 7, 6:52 PM EDTSpecial Marine WarningLWX2 hr
Aug 7, 7:08 PM EDTSevere Thunderstorm WarningLWXAugusta, City of Waynesboro52 min
Aug 6, 9:07 PM EDTSevere Thunderstorm WarningLWXFrederick38 min
Aug 7, 2:48 PM EDTSevere Thunderstorm WarningLWXCarroll, Frederick36 min
Aug 7, 4:26 PM EDTSevere Thunderstorm WarningLWXAllegany49 min
Aug 7, 4:53 PM EDTSevere Thunderstorm WarningLWXAllegany27 min
Aug 7, 5:03 PM EDTSevere Thunderstorm WarningLWXAllegany42 min
Aug 7, 5:28 PM EDTAreal Flood WarningLWXBaltimore, Harford4 hr
Aug 7, 5:36 PM EDTSevere Thunderstorm WarningLWXBaltimore, Harford39 min
Aug 7, 6:04 PM EDTSevere Thunderstorm WarningLWXHarford41 min
Aug 7, 6:12 PM EDTSevere Thunderstorm WarningLWXBaltimore, Harford48 min
Aug 7, 6:15 PM EDTAreal Flood WarningLWXHarford6 hr
Aug 7, 7:39 PM EDTAreal Flood WarningLWXAnne Arundel, Baltimore5 hr
Aug 7, 7:41 PM EDTFlash Flood Warning Considerable damage threatLWXBaltimore, Harford104 min
Aug 7, 5:15 PM EDTSevere Thunderstorm WarningLWXPendleton45 min
Aug 7, 5:40 PM EDTSevere Thunderstorm WarningLWXPendleton50 min

Nearby

Severe Thunderstorm Warnings in Maryland, 2020Severe Thunderstorm Warnings in West Virginia, 2020Every 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.