Alert archive / Virginia / Flash Flood Warnings in 2020

Flash Flood Warning 52, NWS Baltimore/Washington

August 22, 2020Augusta County, City of Staunton, City of Waynesboro, Virginia

NWS Baltimore/Washington issued this flash flood warning at Aug 22, 2020, 10:07 PM EDT for Augusta County, City of Staunton, City of Waynesboro, Virginia. It was in force for 4 hr. 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 22, 2020, 10:07 PM EDT (02:07 UTC)
Expired
Aug 23, 2020, 2:00 AM EDT
In force
4 hr
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

Counties Augusta County, VA, City of Staunton, VA, City of Waynesboro, VA

The radar

The Sterling radar (KLWX), 164 km from the middle of the area, began a volume at 02:09 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

Roanoke, VA (KRNK), launched 00:00Z, 2.1 hours before the alert went out and 111 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, Roanoke, VA at 00:00Z on 2020-08-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 181 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, Roanoke, VA at 00:00Z on 2020-08-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 85 square meters per square second.19395878Sfc1 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
181 J/kg
Mixed-layer CIN
-58 J/kg
Mixed-layer LCL
1183 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
85 m²/s²
0-3 km storm-relative helicity
97 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood 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 flash flood warning went out at Aug 22, 9:28 PM EDT, 39 minutes earlier.

Area forecast discussion, Aug 22, 9:28 PM EDT, 39 minutes before
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Hazardous weather outlook, Aug 22, 1:30 PM EDT, 8 hours 37 minutes before
Hazardous Weather Outlook
National Weather Service Baltimore MD/Washington DC
130 PM EDT Sat Aug 22 2020

ANZ530>543-DCZ001-MDZ011-013-014-016>018-508-VAZ052>057-231000-
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-
130 PM EDT Sat Aug 22 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...This Afternoon and Tonight

Heavy rain from thunderstorms may produce localized flooding late
this afternoon and evening.

Scattered thunderstorms may produce gusty winds over the waters.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

Damaging wind gusts from organized severe thunderstorms are
possible on Tuesday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

MDZ003>006-501>507-VAZ025>031-036>040-050-051-501>508-WVZ050>053-
055-501>506-231000-
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-
130 PM EDT Sat Aug 22 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...This Afternoon and Tonight

A Flash Flood Watch is in effect for Pendleton County in West
Virginia, as well as Highland, Rockingham, and Augusta counties in
Virginia until midnight. Elsewhere, localized flooding is possible
through this evening, especially near and south of Interstate 66
and US 50.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

Damaging wind gusts from organized severe thunderstorms are
possible on Tuesday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

In the hours before

Local storm report, Aug 22, 6:56 PM EDT, 3 hours 11 minutes before
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Local storm report, Aug 22, 9:40 PM EDT, 27 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Aug 22, 8:29 PM EDTAreal Flood WarningLWXAlbemarle, Augusta, Nelson, City of Staunton, City of Waynesboro6 hr
Aug 22, 9:37 PM EDTFlash Flood Warning Considerable damage threatLWXAugusta, Nelson4 hr
Aug 23, 4:24 PM EDTSpecial Marine WarningLWX2 hr
Aug 23, 5:51 PM EDTSpecial Marine WarningLWX114 min
Aug 23, 7:09 PM EDTSpecial Marine WarningLWX87 min
Aug 23, 4:23 PM EDTSevere Thunderstorm WarningLWXBaltimore, Harford52 min
Aug 23, 5:01 PM EDTSevere Thunderstorm WarningLWXFrederick44 min
Aug 23, 5:29 PM EDTSevere Thunderstorm WarningLWXCarroll, Frederick, Howard, Montgomery46 min
Aug 23, 6:58 PM EDTSevere Thunderstorm WarningLWXBaltimore, City of Baltimore47 min
Aug 23, 7:34 PM EDTAreal Flood WarningLWXBaltimore, City of Baltimore2 hr
Aug 23, 7:45 PM EDTFlash Flood Warning Considerable damage threatLWXBaltimore81 min
Aug 23, 7:49 PM EDTAreal Flood WarningLWXPendleton116 min

Nearby

Flash Flood Warnings in Virginia, 2020Every flash flood 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.