Alert archive / Virginia / Flash Flood Warnings in 2018

Flash Flood Warning 59, NWS Baltimore/Washington

July 25, 2018Prince William County, Virginia

NWS Baltimore/Washington issued this flash flood warning at Jul 25, 2018, 6:25 PM EDT for Prince William County, 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
Jul 25, 2018, 6:25 PM EDT (22:25 UTC)
Expired
Jul 25, 2018, 9:30 PM EDT
In force
3 hr
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon
Flood severity
None

County Prince William County, VA

The radar

The Sterling radar (KLWX), 30 km from the middle of the area, began a volume at 22:28 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, 10.4 hours before the alert went out and 28 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 2018-07-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 305 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 2018-07-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 62 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
305 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
553 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
62 m²/s²
0-3 km storm-relative helicity
72 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.7

Open this sounding in Storm Lab

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 24, 9:50 PM EDTSpecial Marine WarningLWX46 min
Jul 25, 12:11 PM EDTAreal Flood WarningLWXFrederick, Shenandoah5 hr
Jul 25, 2:30 PM EDTAreal Flood WarningLWXFrederick7 hr
Jul 25, 4:41 PM EDTAreal Flood WarningLWXFairfax, Loudoun, Prince William, City of Manassas, City of Manassas Park21 hr
Jul 25, 5:26 PM EDTAreal Flood WarningLWXPage, Rockingham, Shenandoah4 hr
Jul 25, 5:56 PM EDTAreal Flood WarningLWXArlington, Fairfax, Prince William, City of Alexandria, City of Fairfax, City of Falls Church11 hr
Jul 25, 6:16 PM EDTFlash Flood WarningLWXArlington, Fairfax, City of Alexandria, City of Fairfax, City of Falls Church3 hr
Jul 25, 7:42 PM EDTAreal Flood WarningLWXSpotsylvania, Stafford, City of Fredericksburg6 hr
Jul 24, 9:45 PM EDTAreal Flood WarningLWXBaltimore, Carroll, City of Baltimore10 hr
Jul 25, 12:58 AM EDTAreal Flood WarningLWXBaltimore6 hr
Jul 25, 5:29 PM EDTAreal Flood WarningLWXBaltimore, Carroll, Frederick, Howard, Montgomery18 hr
Jul 25, 6:00 PM EDTFlash Flood WarningLWXCarroll3 hr
Jul 25, 6:54 PM EDTAreal Flood WarningLWXAnne Arundel, Baltimore, Harford, Howard, City of Baltimore28 hr
Jul 25, 7:27 PM EDTFlash Flood WarningLWXBaltimore, City of Baltimore3 hr

Nearby

Flash Flood Warnings in Virginia, 2018Every flash flood warning in 2018

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.