Alert archive / Virginia / Flash Flood Warnings in 2020

Flash Flood Warning 54, NWS Baltimore/Washington

August 24, 2020Spotsylvania County, Virginia

NWS Baltimore/Washington issued this flash flood warning at Aug 24, 2020, 7:29 PM EDT for Spotsylvania County, Virginia. It was in force for 93 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 24, 2020, 7:29 PM EDT (23:29 UTC)
Expired
Aug 24, 2020, 9:02 PM EDT
In force
93 min
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Spotsylvania County, VA

The radar

The Sterling radar (KLWX), 89 km from the middle of the area, began a volume at 23:30 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, 11.5 hours before the alert went out and 88 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 2020-08-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1012 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 2020-08-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -7 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
1012 J/kg
Mixed-layer CIN
-64 J/kg
Mixed-layer LCL
913 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
-7 m²/s²
0-3 km storm-relative helicity
32 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.5

Open this sounding in Storm Lab

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 24, 1:44 AM EDTSmall Craft AdvisoryLWX7 hr
Aug 24, 1:22 PM EDTSpecial Marine WarningLWX38 min
Aug 24, 1:39 PM EDTSevere Thunderstorm WarningLWXArlington, Fairfax, City of Alexandria39 min
Aug 24, 1:58 PM EDTSpecial Marine WarningLWX21 min
Aug 24, 2:16 PM EDTSevere Thunderstorm WarningLWXCulpeper, Madison, Page, Rappahannock44 min
Aug 24, 2:31 PM EDTSevere Thunderstorm WarningLWXFauquier44 min
Aug 24, 2:54 PM EDTSpecial Marine WarningLWX74 min
Aug 24, 3:14 PM EDTSpecial Marine WarningLWX65 min
Aug 24, 3:14 PM EDTSpecial Marine WarningLWX51 min
Aug 24, 3:27 PM EDTSevere Thunderstorm WarningLWXPrince William, Stafford48 min
Aug 24, 3:29 PM EDTSevere Thunderstorm WarningLWXFairfax, Fauquier, Prince William, Stafford, City of Manassas, City of Manassas Park35 min
Aug 24, 3:57 PM EDTSpecial Marine WarningLWX18 min
Aug 24, 4:35 PM EDTSmall Craft AdvisoryLWX30 hr
Aug 24, 4:44 PM EDTSevere Thunderstorm WarningLWXKing George, Spotsylvania, Stafford, City of Fredericksburg46 min
Aug 24, 4:46 PM EDTSpecial Marine WarningLWX29 min
Aug 24, 4:46 PM EDTSevere Thunderstorm WarningLWXKing George30 min
Aug 24, 4:59 PM EDTSpecial Marine WarningLWX91 min
Aug 24, 5:14 PM EDTSevere Thunderstorm WarningLWXKing George, Spotsylvania, Stafford, City of Fredericksburg46 min
Aug 24, 6:19 PM EDTSevere Thunderstorm WarningLWXSpotsylvania41 min
Aug 24, 6:59 PM EDTAreal Flood WarningLWXSpotsylvania3 hr
Aug 24, 2:38 PM EDTSevere Thunderstorm WarningLWXFrederick, Washington20 min
Aug 24, 2:51 PM EDTSevere Thunderstorm WarningLWXAnne Arundel, Howard, City of Baltimore39 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.