Alert archive / Maryland / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 252, NWS Baltimore/Washington

July 17, 20214 counties in Maryland

NWS Baltimore/Washington issued this severe thunderstorm warning at Jul 17, 2021, 3:24 PM EDT for 4 counties in Maryland. It was in force for 24 min. 1 report 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 17, 2021, 3:24 PM EDT (19:24 UTC)
Expired: Jul 17, 2021, 3:48 PM EDT
In force: 24 min
Issued by: NWS Baltimore/Washington
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Baltimore County, MD, Carroll County, MD, Frederick County, MD, Howard County, MD

The radar

The Sterling radar (KLWX), 68 km from the middle of the area, began a volume at 19:24 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

Time	Report	Where	Remark
Jul 17, 3:31 PM EDT	TSTM WND DMG	2 Ese Winfield, MD	TREE DOWN ON BUSHEY ROAD NEAR OLD WASHINGTON ROAD.

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jul 17, 1:13 PM EDT	Severe Thunderstorm Watch	SPC	10 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 7.4 hours before the alert went out and 66 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 538 J/kg
Mixed-layer CIN: -141 J/kg
Mixed-layer LCL: 1337 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 37 m²/s²
0-3 km storm-relative helicity: 43 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

589 
WUUS51 KLWX 171924
SVRLWX
MDC005-013-021-027-172015-
/O.NEW.KLWX.SV.W.0252.210717T1924Z-210717T2015Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Baltimore MD/Washington DC
324 PM EDT Sat Jul 17 2021

The National Weather Service in Sterling Virginia has issued a

* Severe Thunderstorm Warning for...
  Central Carroll County in north central Maryland...
  Northwestern Howard County in central Maryland...
  East central Frederick County in north central Maryland...
  West central Baltimore County in northern Maryland...

* Until 415 PM EDT.

* At 323 PM EDT, a severe thunderstorm was located near Mount Airy,
  or 11 miles south of Westminster, moving northeast at 30 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  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...
  Westminster, Eldersburg, Mount Airy, Hampstead, Sykesville, Gamber,
  New Windsor, Finksburg, Carrollton, Upperco, Winfield, Louisville,
  Boring, Watersville, Patapsco, Reese, Uniontown, Woodbine, Wagners
  Mill and Marston.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3933 7703 3939 7716 3969 7710 3959 7676
TIME...MOT...LOC 1923Z 208DEG 28KT 3943 7708 

HAIL...1.00IN
WIND...60MPH
 
$$

CJL

1 follow-up statement

774 
WWUS51 KLWX 171948 RRA
SVSLWX

Severe Weather Statement
National Weather Service Baltimore MD/Washington DC
348 PM EDT Sat Jul 17 2021

MDC005-013-021-027-171958-
/O.CAN.KLWX.SV.W.0252.000000T0000Z-210717T2015Z/
Carroll MD-Howard MD-Frederick MD-Baltimore MD-
348 PM EDT Sat Jul 17 2021

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL CARROLL COUNTY IN
NORTH CENTRAL MARYLAND...NORTHWESTERN HOWARD COUNTY IN CENTRAL
MARYLAND...EAST CENTRAL FREDERICK COUNTY IN NORTH CENTRAL MARYLAND
AND WEST CENTRAL BALTIMORE COUNTIES IN NORTHERN MARYLAND IS
CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 1100 PM EDT for
northern, central and north central Maryland.

LAT...LON 3933 7703 3939 7716 3969 7710 3959 7676
TIME...MOT...LOC 1946Z 208DEG 28KT 3961 7696 

$$

CJL

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 16, 10:20 PM EDT	Flash Flood Watch	LWX	Anne Arundel, Baltimore, Cecil, Harford, Howard, Montgomery and 2 more	24 hr
Jul 17, 1:29 PM EDT	Severe Thunderstorm Warning	LWX	Baltimore, Carroll, Howard	46 min
Jul 17, 2:40 PM EDT	Severe Thunderstorm Warning	LWX	Baltimore, Cecil, Harford, City of Baltimore	50 min
Jul 17, 2:59 PM EDT	Severe Thunderstorm Warning	LWX	Baltimore, Harford, City of Baltimore	31 min
Jul 17, 3:27 PM EDT	Severe Thunderstorm Warning	LWX	Baltimore, Harford, City of Baltimore	63 min
Jul 17, 3:30 PM EDT	Severe Thunderstorm Warning	LWX	Montgomery	45 min
Jul 17, 3:34 PM EDT	Flash Flood Warning Considerable damage threat	LWX	Baltimore, City of Baltimore	2 hr
Jul 17, 3:50 PM EDT	Severe Thunderstorm Warning	LWX	Baltimore, Carroll, Frederick, Howard, Montgomery	40 min
Jul 17, 3:59 PM EDT	Severe Thunderstorm Warning	LWX	Anne Arundel, Baltimore, Howard, City of Baltimore	46 min
Jul 17, 4:12 PM EDT	Severe Thunderstorm Warning	LWX	Montgomery	36 min
Jul 17, 4:28 PM EDT	Severe Thunderstorm Warning	LWX	Anne Arundel, Baltimore, City of Baltimore	62 min
Jul 17, 4:45 PM EDT	Flash Flood Warning Considerable damage threat	LWX	Baltimore	101 min
Jul 17, 5:20 PM EDT	Severe Thunderstorm Warning	LWX	Allegany, Washington	40 min
Jul 17, 5:44 PM EDT	Severe Thunderstorm Warning	LWX	Carroll, Frederick, Washington	46 min
Jul 17, 6:01 PM EDT	Areal Flood Warning	LWX	Baltimore, City of Baltimore	6 hr
Jul 17, 6:26 PM EDT	Areal Flood Warning	LWX	Baltimore	5 hr
Jul 17, 6:35 PM EDT	Severe Thunderstorm Warning	LWX	Frederick, Washington	40 min
Jul 17, 6:45 PM EDT	Severe Thunderstorm Warning	LWX	Frederick, Washington	30 min
Jul 17, 7:11 PM EDT	Severe Thunderstorm Warning	LWX	Carroll, Frederick, Howard, Montgomery	49 min
Jul 17, 7:55 PM EDT	Severe Thunderstorm Warning	LWX	Baltimore, Carroll, Harford	27 min

Nearby

Severe Thunderstorm Warnings in Maryland, 2021 Every severe thunderstorm warning in 2021

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.