Alert archive / Virginia / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 310, NWS Baltimore/Washington

July 30, 20204 counties in Virginia; Charles County, Maryland

NWS Baltimore/Washington issued this severe thunderstorm warning at Jul 30, 2020, 6:43 PM EDT for 4 counties in Virginia; Charles County, Maryland. It was in force for 47 min. 4 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Jul 30, 2020, 6:43 PM EDT (22:43 UTC)
Expired
Jul 30, 2020, 7:30 PM EDT
In force
47 min
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Charles County, MD, City of Fredericksburg, VA, King George County, VA, Spotsylvania County, VA, Stafford County, VA

The radar

The Sterling radar (KLWX), 77 km from the middle of the area, began a volume at 22:44 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.

What was reported inside it

TimeReportWhereRemark
Jul 30, 6:57 PM EDTTSTM WND DMG1 Wsw Weedonville, VADOWNED TREE NEAR THE INTERSECTION OF VA 206 (DAHLGREN RD) AND VA 610 (INDIANTOWN RD)
Jul 30, 7:10 PM EDTTSTM WND DMGNanjemoy, MDMULTIPLE TREES DOWN AROUND NANJEMOY
Jul 30, 7:11 PM EDTMARINE TSTM WIND 402 Se Dahlgren, VA
Jul 30, 7:25 PM EDTTSTM WND DMGMarbury, MDMULTIPLE TREES DOWN AROUND MARBURY

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 10.7 hours before the alert went out and 71 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 2020-07-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 20 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2020-07-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -22 square meters per square second.193958Sfc1 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
20 J/kg
Mixed-layer CIN
-178 J/kg
Mixed-layer LCL
1679 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
-22 m²/s²
0-3 km storm-relative helicity
58 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

666 
WUUS51 KLWX 302243
SVRLWX
MDC017-VAC099-177-179-630-302330-
/O.NEW.KLWX.SV.W.0310.200730T2243Z-200730T2330Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Baltimore MD/Washington DC
643 PM EDT Thu Jul 30 2020

The National Weather Service in Sterling Virginia has issued a

* Severe Thunderstorm Warning for...
  Southwestern Charles County in southern Maryland...
  Southeastern Stafford County in northern Virginia...
  King George County in central Virginia...
  The City of Fredericksburg in central Virginia...
  Northeastern Spotsylvania County in central Virginia...

* Until 730 PM EDT.

* At 642 PM EDT, severe thunderstorms were located along a line
  extending from near Fredericksburg to 6 miles northwest of Port
  Royal to 6 miles southeast of Bowling Green, moving northeast at 35
  mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Damaging winds will cause some trees and large branches 
           to fall. This could injure those outdoors, as well as 
           damage homes and vehicles. Roadways may become blocked by 
           downed trees. Localized power outages are possible. 
           Unsecured light objects may become projectiles.

* Locations impacted include...
  Stafford, Fredericksburg, La Plata, King George, Dahlgren,
  Quantico, Fairview Beach, Nanjemoy Creek, Popes Creek, Aquia Creek,
  Potomac Creek, Port Tobacco River, Cherry Hill, Falmouth,
  Passapatanzy, Port Tobacco Village, Issue, Tompkinsville, Ramoth
  and Pisgah.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3826 7688 3835 7700 3828 7698 3826 7704
      3814 7707 3820 7722 3819 7725 3825 7724
      3825 7727 3822 7728 3825 7737 3819 7744
      3828 7762 3853 7738 3850 7730 3861 7725
      3856 7724 3859 7719 3851 7692 3830 7683
TIME...MOT...LOC 2242Z 219DEG 30KT 3831 7758 3821 7731 3800 7724 

HAIL...<.75IN
WIND...60MPH
 
$$

JMG
1 follow-up statement
794 
WWUS51 KLWX 302317
SVSLWX

Severe Weather Statement
National Weather Service Baltimore MD/Washington DC
717 PM EDT Thu Jul 30 2020

VAC177-630-302327-
/O.CAN.KLWX.SV.W.0310.000000T0000Z-200730T2330Z/
City of Fredericksburg VA-Spotsylvania VA-
717 PM EDT Thu Jul 30 2020

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN SPOTSYLVANIA
COUNTY AND THE CITY OF FREDERICKSBURG IS CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

LAT...LON 3826 7688 3835 7700 3828 7698 3826 7704
      3827 7705 3837 7729 3853 7738 3850 7730
      3855 7728 3856 7726 3858 7727 3861 7725
      3856 7724 3859 7719 3851 7692 3839 7687
      3838 7688 3837 7686 3830 7683
TIME...MOT...LOC 2317Z 219DEG 30KT 3853 7735 3843 7708 3822 7701 

$$

MDC017-VAC099-179-302330-
/O.CON.KLWX.SV.W.0310.000000T0000Z-200730T2330Z/
Charles MD-Stafford VA-King George VA-
717 PM EDT Thu Jul 30 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 PM EDT
FOR SOUTHWESTERN CHARLES...NORTHEASTERN STAFFORD AND NORTHEASTERN
KING GEORGE COUNTIES...

At 717 PM EDT, severe thunderstorms were located along a line
extending from Triangle to near Port Tobacco River to near Colonial
Beach, moving northeast at 35 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Damaging winds will cause some trees and large branches to 
         fall. This could injure those outdoors, as well as damage 
         homes and vehicles. Roadways may become blocked by downed 
         trees. Localized power outages are possible. Unsecured 
         light objects may become projectiles.

Locations impacted include...
La Plata, Dahlgren, Quantico, Nanjemoy Creek, Popes Creek, Port
Tobacco River, Cherry Hill, Port Tobacco Village, Issue,
Tompkinsville, Ironsides, Bel Alton, Swan Point, Pisgah, Faulkner,
Berthaville, Marbury, Widewater, Port Tobacco and Ripley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3826 7688 3835 7700 3828 7698 3826 7704
      3827 7705 3837 7729 3853 7738 3850 7730
      3855 7728 3856 7726 3858 7727 3861 7725
      3856 7724 3859 7719 3851 7692 3839 7687
      3838 7688 3837 7686 3830 7683
TIME...MOT...LOC 2317Z 219DEG 30KT 3853 7735 3843 7708 3822 7701 

HAIL...<.75IN
WIND...60MPH
 
$$

JMG

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 30, 4:34 PM EDTAreal Flood WarningLWXAugusta, City of Waynesboro3 hr
Jul 30, 4:59 PM EDTSpecial Marine WarningLWX43 min
Jul 30, 5:08 PM EDTSevere Thunderstorm WarningLWXKing George38 min
Jul 30, 5:25 PM EDTSevere Thunderstorm WarningLWXMadison, Page, Rappahannock27 min
Jul 30, 5:41 PM EDTSpecial Marine WarningLWX64 min
Jul 30, 6:04 PM EDTSpecial Marine WarningLWX56 min
Jul 30, 6:28 PM EDTSpecial Marine WarningLWX92 min
Jul 30, 6:45 PM EDTSpecial Marine WarningLWX77 min
Jul 30, 6:58 PM EDTSpecial Marine WarningLWX92 min
Jul 30, 7:14 PM EDTSevere Thunderstorm WarningLWXArlington, Fairfax, King George, Prince William, City of Alexandria, City of Fairfax and 3 more46 min
Jul 30, 7:49 PM EDTSpecial Marine WarningLWX86 min
Jul 30, 1:06 PM EDTHeat AdvisoryLWXAnne Arundel, Baltimore, Calvert, Harford, Saint Mary's, City of Baltimore6 hr
Jul 30, 5:34 PM EDTSevere Thunderstorm WarningLWXCharles12 min
Jul 30, 7:42 PM EDTSevere Thunderstorm WarningLWXAnne Arundel, Calvert, Prince George's48 min

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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.