Alert archive / Virginia / Flash Flood Warnings in 2020

Flash Flood Warning 7, NWS Baltimore/Washington

June 23, 2020Loudoun County, Virginia; Frederick County, Maryland

NWS Baltimore/Washington issued this flash flood warning at Jun 23, 2020, 9:50 PM EDT for Loudoun County, Virginia; Frederick County, Maryland. It was in force for 2 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: Jun 23, 2020, 9:50 PM EDT (01:50 UTC)
Expired: Jun 23, 2020, 11:57 PM EDT
In force: 2 hr
Issued by: NWS Baltimore/Washington
Area: Storm-based polygon
Flood severity: None

Counties Frederick County, MD, Loudoun County, VA

The radar

The Sterling radar (KLWX), 34 km from the middle of the area, began a volume at 01:52 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 00:00Z, 1.8 hours before the alert went out and 38 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: 827 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 1445 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 65 m²/s²
0-3 km storm-relative helicity: 130 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.8

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 Jun 23, 9:37 PM EDT, 13 minutes earlier.

Area forecast discussion, Jun 23, 9:37 PM EDT, 13 minutes before

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Hazardous weather outlook, Jun 23, 9:01 PM EDT, 49 minutes before

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In the hours before

Local storm report, Jun 23, 4:38 PM EDT, 5 hours 12 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
438 PM EDT TUE JUN 23 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0438 PM     TSTM WND DMG     3 WSW CAPON BRIDGE      39.28N  78.48W
06/23/2020                   HAMPSHIRE          WV   TRAINED SPOTTER

            LARGE BRANCHES BEING BLOWN DOWN AT SPOTTER'S HOME IN
            CAPON BRIDGE.

&&

EVENT NUMBER LWX2001268

DH

Local storm report, Jun 23, 5:49 PM EDT, 4 hours 1 minute before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
549 PM EDT TUE JUN 23 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0546 PM     HAIL             INWOOD                  39.35N  78.05W
06/23/2020  E1.00 INCH       BERKELEY           WV   TRAINED SPOTTER

&&

EVENT NUMBER LWX2001269

IMR

Local storm report, Jun 23, 6:01 PM EDT, 3 hours 49 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
601 PM EDT TUE JUN 23 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0550 PM     TSTM WND DMG     2 E INWOOD              39.35N  78.01W
06/23/2020                   BERKELEY           WV   911 CALL CENTER

            TREE DAMAGE NEAR INWOOD, INCLUDING A TREE DOWN ON POWER
            LINES NEAR THE INTERSECTION OF CHOPWOOD ROAD AND SULPHUR
            SPRINGS ROAD.

&&

EVENT NUMBER LWX2001270

DH

Local storm report, Jun 23, 7:16 PM EDT, 2 hours 34 minutes before

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Local storm report, Jun 23, 7:49 PM EDT, 2 hours 1 minute before

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Nearby

Flash Flood Warnings in Virginia, 2020 Flash Flood Warnings in Maryland, 2020 Every 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.