Alert archive / Virginia / Severe Thunderstorm Warnings in 2019

Severe Thunderstorm Warning 643, NWS Baltimore/Washington

September 2, 2019Fairfax County, Prince William County, Virginia

NWS Baltimore/Washington issued this severe thunderstorm warning at Sep 2, 2019, 6:13 PM EDT for Fairfax County, Prince William County, Virginia. It was in force for 28 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
Sep 2, 2019, 6:13 PM EDT (22:13 UTC)
Expired
Sep 2, 2019, 6:41 PM EDT
In force
28 min
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Fairfax County, VA, Prince William County, VA

The radar

The Sterling radar (KLWX), 25 km from the middle of the area, began a volume at 22:14 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, 10.2 hours before the alert went out and 20 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 2019-09-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 594 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 2019-09-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 102 square meters per square second.1939Sfc1 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
594 J/kg
Mixed-layer CIN
-3 J/kg
Mixed-layer LCL
584 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
102 m²/s²
0-3 km storm-relative helicity
119 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.4

Open this sounding in Storm Lab

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 2, 3:40 PM EDTSevere Thunderstorm WarningLWXLoudoun50 min
Sep 2, 4:27 PM EDTSevere Thunderstorm WarningLWXLoudoun48 min
Sep 2, 4:53 PM EDTSevere Thunderstorm WarningLWXFairfax, Fauquier, Loudoun, Prince William37 min
Sep 2, 4:55 PM EDTSpecial Marine WarningLWX39 min
Sep 2, 5:17 PM EDTSpecial Marine WarningLWX118 min
Sep 2, 5:36 PM EDTSevere Thunderstorm WarningLWXPrince William24 min
Sep 2, 5:48 PM EDTSpecial Marine WarningLWX87 min
Sep 2, 5:52 PM EDTSevere Thunderstorm WarningLWXPrince William38 min
Sep 2, 6:26 PM EDTSevere Thunderstorm WarningLWXFairfax, Prince William49 min
Sep 2, 6:59 PM EDTSpecial Marine WarningLWX17 min
Sep 2, 7:05 PM EDTSevere Thunderstorm WarningLWXKing George40 min
Sep 2, 7:13 PM EDTSpecial Marine WarningLWX43 min
Sep 2, 7:23 PM EDTSevere Thunderstorm WarningLWXFauquier30 min
Sep 2, 2:35 PM EDTCoastal Flood AdvisoryLWXAnne Arundel, Saint Mary's11 hr
Sep 2, 5:10 PM EDTSevere Thunderstorm WarningLWXBaltimore, Carroll, Harford50 min
Sep 2, 5:54 PM EDTSevere Thunderstorm WarningLWXBaltimore, Harford39 min
Sep 2, 6:32 PM EDTSevere Thunderstorm WarningLWXBaltimore, Harford25 min

Nearby

Severe Thunderstorm Warnings in Virginia, 2019Every severe thunderstorm 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.