Alert archive / Virginia / Severe Thunderstorm Warnings in 2019

Severe Thunderstorm Warning 367, NWS Baltimore/Washington

July 17, 2019Fauquier County, Loudoun County, Prince William County, Virginia

NWS Baltimore/Washington issued this severe thunderstorm warning at Jul 17, 2019, 4:12 PM EDT for Fauquier County, Loudoun County, Prince William County, Virginia. It was in force for 48 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
Jul 17, 2019, 4:12 PM EDT (20:12 UTC)
Expired
Jul 17, 2019, 5:00 PM EDT
In force
48 min
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Fauquier County, VA, Loudoun County, VA, Prince William County, VA

The radar

The Sterling radar (KLWX), 20 km from the middle of the area, began a volume at 20:12 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, 8.2 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-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2019-07-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 237 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 2019-07-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 67 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
237 J/kg
Mixed-layer CIN
-90 J/kg
Mixed-layer LCL
1666 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
67 m²/s²
0-3 km storm-relative helicity
69 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm 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 severe thunderstorm warning went out at Jul 17, 3:23 PM EDT, 49 minutes earlier.

Area forecast discussion, Jul 17, 3:23 PM EDT, 49 minutes before
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Hazardous weather outlook, Jul 17, 5:10 AM EDT, 11 hours 2 minutes before
Hazardous Weather Outlook
National Weather Service Baltimore MD/Washington DC
510 AM EDT Wed Jul 17 2019

ANZ530>543-DCZ001-MDZ011-013-014-016>018-508-VAZ052>057-180915-
Chesapeake Bay north of Pooles Island MD-
Chesapeake Bay from Pooles Island to Sandy Point MD-
Chesapeake Bay from Sandy Point to North Beach MD-
Chesapeake Bay from North Beach to Drum Point MD-
Chesapeake Bay from Drum Point MD to Smith Point VA-
Tidal Potomac from Key Bridge to Indian Head MD-
Tidal Potomac from Indian Head to Cobb Island MD-
Tidal Potomac from Cobb Island MD to Smith Point VA-
Patapsco River including Baltimore Harbor-
Chester River to Queenstown MD-Eastern Bay-
Choptank River to Cambridge MD and the Little Choptank River-
Patuxent River to Broomes Island MD-
Tangier Sound and the inland waters surrounding Bloodsworth
Island-District of Columbia-Southern Baltimore-Prince Georges-
Anne Arundel-Charles-St. Marys-Calvert-Southeast Harford-
Prince William/Manassas/Manassas Park-Fairfax-
Arlington/Falls Church/Alexandria-Stafford-Spotsylvania-
King George-
510 AM EDT Wed Jul 17 2019

This Hazardous Weather Outlook is for the Maryland portion of the
Chesapeake Bay, Tidal Potomac River, and adjacent counties in
central Maryland and northern Virginia as well as the District of
Columbia.

.DAY ONE...Today and Tonight

A Heat Advisory is in effect for the entire area from 11 AM late
this morning until 8 PM this evening.

Thunderstorms may be capable of producing isolated damaging wind
gusts or instances of flooding this afternoon and evening,
especially over northern and northeastern Maryland.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Heat indices may approach 105 degrees Thursday afternoon.

Dangerous heat and humidity are likely Friday through Sunday
across the entire area. Heat indices of 110 to 115 degrees are
possible during the afternoon and evening hours each day, and heat
indices may hold in the 80s and 90s at night. If the prolonged
heat and humidity is realized, it will become a significant threat
to anyone exposed to the heat for an extended period of time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

MDZ003>006-501>507-VAZ025>031-036>040-050-051-501>508-WVZ050>053-
055-501>506-180915-
Washington-Frederick MD-Carroll-Northern Baltimore-
Extreme Western Allegany-Central and Eastern Allegany-
Northwest Montgomery-Central and Southeast Montgomery-
Northwest Howard-Central and Southeast Howard-Northwest Harford-
Augusta-Rockingham-Shenandoah-Frederick VA-Page-Warren-Clarke-
Nelson-Albemarle-Greene-Madison-Rappahannock-Orange-Culpeper-
Northern Fauquier-Southern Fauquier-Western Highland-
Eastern Highland-Western Loudoun-Eastern Loudoun-
Northern Virginia Blue Ridge-Central Virginia Blue Ridge-
Hampshire-Morgan-Berkeley-Jefferson-Hardy-Western Grant-
Eastern Grant-Western Mineral-Eastern Mineral-Western Pendleton-
Eastern Pendleton-
510 AM EDT Wed Jul 17 2019

This Hazardous Weather Outlook is for eastern West Virginia,
northern and central Virginia, and central and western Maryland
with the exception of Garrett County.

.DAY ONE...Today and Tonight

A Heat Advisory is in effect for southeastern Howard and
southeastern Montgomery Counties in Maryland from 11 AM late this
morning through 8 PM this evening.

Thunderstorms may be capable of producing isolated damaging wind
gusts or instances of flooding this afternoon and evening,
especially over northern and northeastern Maryland.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Heat indices around 100 degrees are possible Thursday afternoon.

Dangerous heat and humidity are likely Friday through Sunday
across the entire area. Heat indices around 105 to 110 degrees are
possible during the afternoon and evening hours each day,
especially in the Valleys and east of the Blue Ridge Mountains. If
the prolonged heat and humidity is realized, it will become a
significant threat to anyone exposed to the heat for an extended
period of time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

DHOF

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 16, 8:49 PM EDTHeat AdvisoryLWXArlington, Fairfax, King George, Spotsylvania, Stafford, City of Alexandria and 3 more22 hr
Jul 17, 2:34 AM EDTSmall Craft AdvisoryLWX20 hr
Jul 17, 2:54 PM EDTSevere Thunderstorm WarningLWXAlbemarle, Augusta, Nelson, City of Waynesboro34 min
Jul 17, 3:18 PM EDTSevere Thunderstorm WarningLWXAlbemarle, Greene, Madison, Orange42 min
Jul 17, 3:40 PM EDTSevere Thunderstorm WarningLWXClarke, Fauquier, Loudoun, Rappahannock, Warren50 min
Jul 17, 4:20 PM EDTSevere Thunderstorm WarningLWXCulpeper, Fauquier, Prince William40 min
Jul 17, 4:25 PM EDTSpecial Marine WarningLWX2 hr
Jul 17, 4:43 PM EDTSevere Thunderstorm WarningLWXFairfax, Loudoun47 min
Jul 17, 4:48 PM EDTSevere Thunderstorm WarningLWXFairfax, Fauquier, Loudoun, Prince William, City of Fairfax, City of Manassas and 1 more42 min
Jul 17, 5:08 PM EDTSevere Thunderstorm WarningLWXFairfax, Prince William, Stafford, City of Alexandria41 min
Jul 17, 5:23 PM EDTSevere Thunderstorm WarningLWXArlington, Fairfax, Loudoun, City of Falls Church52 min
Jul 17, 5:30 PM EDTSpecial Marine WarningLWX103 min
Jul 17, 5:35 PM EDTSevere Thunderstorm WarningLWXArlington, Fairfax, City of Alexandria40 min
Jul 17, 5:47 PM EDTSpecial Marine WarningLWX69 min
Jul 17, 7:47 PM EDTSpecial Marine WarningLWX33 min
Jul 17, 4:53 PM EDTSevere Thunderstorm WarningLWXCarroll, Frederick52 min
Jul 17, 5:12 PM EDTSevere Thunderstorm WarningLWXBaltimore, Carroll, Frederick, Howard, Montgomery48 min
Jul 17, 5:46 PM EDTSevere Thunderstorm WarningLWXBaltimore, Carroll, Harford, City of Baltimore59 min
Jul 17, 6:08 PM EDTSevere Thunderstorm WarningLWXAnne Arundel, Baltimore, Harford, Howard, City of Baltimore52 min
Jul 17, 6:31 PM EDTSevere Thunderstorm WarningLWXHarford44 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.