Alert archive / Virginia / Severe Thunderstorm Warnings in 2020
Severe Thunderstorm Warning 232, NWS Baltimore/Washington
NWS Baltimore/Washington issued this severe thunderstorm warning at Jul 20, 2020, 6:00 PM EDT for Fairfax County, City of Alexandria, Virginia; Prince George's County, Maryland. It was in force for 45 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 20, 2020, 6:00 PM EDT (22:00 UTC)
- Expired
- Jul 20, 2020, 6:45 PM EDT
- In force
- 45 min
- Issued by
- NWS Baltimore/Washington
- Area
- Storm-based polygon
- Hail
- 1.0 in
- Wind
- 60.0 mph
Counties Prince George's County, MD, City of Alexandria, VA, Fairfax County, VA
The radar
The Sterling radar (KLWX), 41 km from the middle of the area, began a volume at 21:59 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, 10.0 hours before the alert went out and 33 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.
- Mixed-layer CAPE
- 109 J/kg
- Mixed-layer CIN
- -181 J/kg
- Mixed-layer LCL
- 1670 m above ground
- 0-6 km bulk shear
- 12 kt
- 0-1 km storm-relative helicity
- -91 m²/s²
- 0-3 km storm-relative helicity
- 7 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
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 20, 2:41 PM EDT, 3 hours 19 minutes earlier.
Area forecast discussion, Jul 20, 2:41 PM EDT, 3 hours 19 minutes before
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</html>Hazardous weather outlook, Jul 20, 8:42 AM EDT, 9 hours 18 minutes before
Hazardous Weather Outlook National Weather Service Baltimore MD/Washington DC 842 AM EDT Mon Jul 20 2020 ANZ530>543-DCZ001-MDZ011-013-014-016>018-508-VAZ052>057-211245- 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- 842 AM EDT Mon Jul 20 2020 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 from noon to 8 PM today for the entire outlook area for heat indices up to 109. An Excessive Heat Warning is in effect from noon to 8 pm today for St. Mary's and Calvert Counties with heat indices around 110 expected. Isolated to scattered thunderstorms this afternoon and evening could produce isolated damaging wind gusts and heavy rain for areas along and south of the Baltimore and D.C. metro and the I-66 corridor. Isolated instances of flash flooding can not be ruled out. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Continued heat and humidity may lead to a heat index near or above 105 degrees Tuesday and Wednesday. Scattered thunderstorms Tuesday and Wednesday could produce isolated damaging wind gusts. Additionally, storms on Tuesday could bring heavy rainfall, with isolated instances of flash flooding not out of the question. .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>506-211245- 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- 842 AM EDT Mon Jul 20 2020 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 from noon until 8 PM today for much of central and northern Virginia, eastern West Virginia, and central and western Maryland for heat indices ranging from 100 to 108. Isolated to scattered thunderstorms this afternoon and evening could produce isolated damaging wind gusts and heavy rain for areas along and south of the Baltimore and D.C. metro and the I-66 corridor. Isolated instances of flash flooding can not be ruled out. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Continued heat and humidity may lead to a heat index near or above 100 degrees Tuesday and Wednesday. Scattered thunderstorms Tuesday and Wednesday could produce isolated damaging wind gusts. Additionally, storms on Tuesday could bring heavy rainfall, with isolated instances of flash flooding not out of the question. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
In the hours before
Local storm report, Jul 20, 5:29 PM EDT, 31 minutes before
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</html>The office that day
Everything else NWS Baltimore/Washington issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 20, 4:48 PM EDT | Severe Thunderstorm Warning | LWX | Culpeper, Greene, Madison, Page, Rappahannock | 42 min |
| Jul 20, 5:13 PM EDT | Special Marine Warning | LWX | 92 min | |
| Jul 20, 5:26 PM EDT | Severe Thunderstorm Warning | LWX | Page, Rockingham, Shenandoah | 33 min |
| Jul 20, 6:05 PM EDT | Special Marine Warning | LWX | 85 min | |
| Jul 20, 6:07 PM EDT | Severe Thunderstorm Warning | LWX | Fairfax, Prince William | 23 min |
| Jul 20, 6:26 PM EDT | Special Marine Warning | LWX | 81 min | |
| Jul 20, 7:38 PM EDT | Special Marine Warning | LWX | 97 min | |
| Jul 20, 7:50 PM EDT | Special Marine Warning | LWX | 79 min | |
| Jul 20, 8:34 AM EDT | Excessive Heat Warning | LWX | Calvert, Saint Mary's | 11 hr |
Nearby
Severe Thunderstorm Warnings in Virginia, 2020Severe Thunderstorm Warnings in Maryland, 2020Every severe thunderstorm 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.