EF1 tornado, Knollwood to Dayton, Maryland, May 30, 2019

1. EF065 to 85 mph

   Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

2. EF186 to 110 mphthis tornado

   Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

3. EF2111 to 135 mph

   Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

4. EF3136 to 165 mph

   Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

5. EF4166 to 200 mph

   Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

6. EF5over 200 mph

   Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

7. Unrated

   The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

Rating

EF1

Date

May 30, 2019

Touchdown

3:20 PM EDT (19:20 UTC)

Lifted

3:27 PM EDT (19:27 UTC)

On the ground

7 minutes

Path length

4.5 miles (7.2 km)

Path width

100 yards (91 m)

Deaths

0

Injuries

0

County

Howard County

Touchdown point

39.258, -77.027

Lift-off point

39.248, -76.944

Record number

1905301320-01

9 damage points were recorded along this path by NWS LWX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 100 mph.

• Few trees uprooted, large branches snapped.
• Few trees uprooted, large branches snapped. Power llines downed.
• Significant sections of roof decking removed. Lofting and downstream carrying of debris. Trees snapped.
• Trees snapped and power lines downed along Tridelphia Road.

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

On the morning of May 30th a surface front was positioned across Pennsylvania, with a surface low positioned west of Chicago, Illinois. Through the day the surface |low moved eastward along the frontal boundary, reaching western Pennsylvania by late in the afternoon. The low then quickly pushed eastward off the NJ coastline by late in the evening, with a cold front crossing the region. In addition, two disturbances aloft moved across the area, one during the mid to late afternoon hours, and another in the evening. Out ahead of the front, warmth and humidity allowed for the development of moderate instability and that coupled with moderate wind shear aloft set the stage for two rounds of scattered showers and thunderstorms, some of which became severe. Two tornadoes occurred across central Maryland.

An EF-1 tornado, with estimated maximum wind speeds around 100 mph, occurred Thursday May 30th 2019 near Glenelg, Maryland. At 3:20 PM EDT (2:20 PM EST), the tornado touched down in a residential community west of Glenelg between Meriweather Drive and Edgewoods Way. As the tornado was passing through the community, it ripped sections of roofing deck off homes. It also snapped and uprooted trees and |large branches, and lofted loose objects hundreds of feet. Moving east-southeast, it crossed over Tridelphia Road and other nearby roads, downing large trees and power lines. As it reached Maryland Route 32 it downed a swath of trees on both sides of the road before moving over and just north of a Howard County Highway Maintenance facility. At the facility, the tornado ripped off its tin roofing, damaged some roof framing, tore a large section of fabric from a salt dome, destroyed garage bay |doors, damaged fencing, and continued to snap and uproot large trees along its path. |Continuing along, it snapped and uprooted large trees in residential areas along Buckskin Lake Drive, Folly Quarter Lane, and Heritage Hill Lane. It also ripped off a section of barn roofing. The tornado lifted at 3:27 PM EDT (2:27 PM EST), over a farm property before it reached Sheppard Lane.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down. One was issued for the county at another hour that day.

The county was under a severe thunderstorm watch, issued at 18:02 UTC and running to 20:21 UTC.

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The Storm Prediction Center had this point in a Slight Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 16:28 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

The Sterling radar (KLWX), 53 km away, was scanning. The volume nearest the touchdown began at 19:20 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

Local storm reports within 60 km of the path, in the three hours either side.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

The live radar over the trackEvery 2019 tornado in MarylandEvery tornado in Maryland since 1950Warnings in force in Maryland nowThe forecast where you are

2 more were confirmed in the United States that day.

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.