Alert archive / Virginia / Flash Flood Warnings in 2019

Flash Flood Warning 1, NWS Baltimore/Washington

May 4, 2019Prince William County, City of Manassas, City of Manassas Park, Virginia

NWS Baltimore/Washington issued this flash flood warning at May 4, 2019, 10:57 PM EDT for Prince William County, City of Manassas, City of Manassas Park, Virginia. It was in force for 3 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: May 4, 2019, 10:57 PM EDT (02:57 UTC)
Expired: May 5, 2019, 2:00 AM EDT
In force: 3 hr
Issued by: NWS Baltimore/Washington
Area: Storm-based polygon
Flood severity: None

Counties City of Manassas, VA, City of Manassas Park, VA, Prince William County, VA

The radar

The Sterling radar (KLWX), 26 km from the middle of the area, began a volume at 03:00 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, 3.0 hours before the alert went out and 24 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: 122 J/kg
Mixed-layer CIN: -37 J/kg
Mixed-layer LCL: 1063 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: -18 m²/s²
0-3 km storm-relative helicity: 97 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.6

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 May 4, 8:35 PM EDT, 2 hours 22 minutes earlier.

Area forecast discussion, May 4, 8:35 PM EDT, 2 hours 22 minutes before

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Hazardous weather outlook, May 4, 8:24 PM EDT, 2 hours 33 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
May 4, 8:19 PM EDT	Small Craft Advisory	LWX		38 hr
May 4, 10:38 PM EDT	Areal Flood Warning	LWX	Culpeper, Fauquier, Prince William, City of Manassas, City of Manassas Park	10 hr
May 4, 11:10 PM EDT	Areal Flood Warning	LWX	Arlington, Fairfax, City of Alexandria, City of Fairfax, City of Falls Church	6 hr
May 5, 1:01 AM EDT	Special Marine Warning	LWX		62 min
May 5, 6:47 AM EDT	Areal Flood Warning	LWX	Clarke, Frederick, City of Winchester	18 hr
May 5, 5:22 PM EDT	Areal Flood Warning	LWX	Fauquier, Prince William	13 hr
May 5, 6:50 PM EDT	Special Marine Warning	LWX		72 min
May 5, 12:02 PM EDT	Areal Flood Warning	LWX	Carroll, Frederick	12 hr
May 5, 7:36 PM EDT	River Flood Warning	LWX	Frederick	17 hr
May 5, 10:56 AM EDT	River Flood Watch	LWX	Berkeley, Jefferson	27 min
May 5, 11:21 AM EDT	River Flood Warning	LWX	Berkeley, Jefferson	33 hr
May 5, 7:57 PM EDT	Areal Flood Warning	LWX	Berkeley	16 hr

Nearby

Flash Flood Warnings in Virginia, 2019 Every flash flood warning in 2019

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.