Alert archive / Pennsylvania / Tornado Watches in 2022

Tornado Watch 251

May 20, 20225 states

The Storm Prediction Center issued this tornado watch at May 20, 2022, 11:35 AM EDT for 5 states. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: May 20, 2022, 11:35 AM EDT (15:35 UTC)
Expired: May 20, 2022, 6:12 PM EDT
In force: 7 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2 in
Strongest gust expected: 60 kt

All 63 counties

New Castle County, DE, Allegany County, MD, Baltimore County, MD, Carroll County, MD, Cecil County, MD, City of Baltimore, MD, Frederick County, MD, Garrett County, MD, Harford County, MD, Howard County, MD, Washington County, MD, Burlington County, NJ, Camden County, NJ, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Morris County, NJ, Ocean County, NJ, Salem County, NJ, Somerset County, NJ, Sussex County, NJ, Warren County, NJ, Adams County, PA, Bedford County, PA, Berks County, PA, Blair County, PA, Bucks County, PA, Carbon County, PA, Centre County, PA, Chester County, PA, Columbia County, PA, Cumberland County, PA, Dauphin County, PA, Delaware County, PA, Franklin County, PA, Fulton County, PA, Huntingdon County, PA, Juniata County, PA, Lackawanna County, PA, Lancaster County, PA, Lebanon County, PA, Lehigh County, PA, Luzerne County, PA, Mifflin County, PA, Monroe County, PA, Montgomery County, PA, Montour County, PA, Northampton County, PA, Northumberland County, PA, Perry County, PA, Philadelphia County, PA, Pike County, PA, Schuylkill County, PA, Snyder County, PA, Union County, PA, York County, PA, Berkeley County, WV, Hampshire County, WV, Jefferson County, WV, Mineral County, WV, Morgan County, WV

The radar

The State College radar (KCCX), 112 km from the middle of the area, began a volume at 15:37 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 SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 40%
One or more EF2 to EF5 tornadoes: 20%
Ten or more severe wind reports: 70%
One or more gusts of 65 knots or more: 20%
Ten or more severe hail reports: 30%
One or more hailstones of 2 inches or more: 30%
Six or more combined severe hail and wind reports: 90%

Warnings issued inside it

29 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
May 20, 11:41 AM EDT	Severe Thunderstorm Warning	LWX	Allegany, Garrett	29 min
May 20, 12:09 PM EDT	Severe Thunderstorm Warning	LWX	Allegany, Garrett, Washington	51 min
May 20, 12:09 PM EDT	Severe Thunderstorm Warning Considerable damage threat	CTP	Bedford, Franklin, Fulton, Huntingdon	81 min
May 20, 12:32 PM EDT	Tornado Warning	LWX	Allegany	10 min
May 20, 12:41 PM EDT	Tornado Warning	LWX	Allegany, Washington	13 min
May 20, 12:53 PM EDT	Severe Thunderstorm Warning	LWX	Washington	17 min
May 20, 1:14 PM EDT	Severe Thunderstorm Warning	CTP	Lancaster	61 min
May 20, 1:18 PM EDT	Severe Thunderstorm Warning	CTP	Adams, Cumberland, Franklin, York	42 min
May 20, 1:41 PM EDT	Severe Thunderstorm Warning	CTP	Cumberland, Dauphin, Lebanon, Perry	34 min
May 20, 1:45 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester, Montgomery	45 min
May 20, 1:58 PM EDT	Severe Thunderstorm Warning	CTP	Lancaster, York	47 min
May 20, 2:11 PM EDT	Severe Thunderstorm Warning	CTP	Dauphin, Lebanon	34 min
May 20, 2:16 PM EDT	Severe Thunderstorm Warning	CTP	York	29 min
May 20, 2:22 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Chester, Lehigh, Montgomery	53 min
May 20, 2:27 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	48 min
May 20, 2:30 PM EDT	Severe Thunderstorm Warning	PHI	Berks	45 min
May 20, 2:33 PM EDT	Severe Thunderstorm Warning Considerable damage threat	CTP	Lancaster	42 min
May 20, 2:52 PM EDT	Severe Thunderstorm Warning	BGM	Lackawanna, Wayne	23 min
May 20, 2:53 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh, Montgomery	52 min
May 20, 3:00 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Gloucester	31 min
May 20, 3:05 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer, Somerset	29 min
May 20, 3:10 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Chester, Lehigh, Montgomery	50 min
May 20, 3:25 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Carbon, Lehigh, Monroe, Northampton	50 min
May 20, 3:37 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	53 min
May 20, 3:41 PM EDT	Severe Thunderstorm Warning Considerable damage threat	PHI	Hunterdon, Mercer, Somerset, Warren	49 min
May 20, 4:33 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Ocean	42 min
May 20, 5:11 PM EDT	Severe Thunderstorm Warning Considerable damage threat	PHI	Burlington, Camden, Ocean	64 min
May 20, 5:20 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth, Ocean	27 min
May 20, 5:54 PM EDT	Severe Thunderstorm Warning	PHI	Ocean	28 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 3.6 hours before the alert went out and 178 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: 1 J/kg
Mixed-layer CIN: -226 J/kg
Mixed-layer LCL: 1469 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 106 m²/s²
0-3 km storm-relative helicity: 169 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.2

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 20, 1:49 PM EDT	Mesoscale Discussion	SPC	New Castle	86 min
May 20, 10:39 AM EDT	Mesoscale Discussion	SPC	Allegany, Carroll, Frederick, Garrett, Washington	96 min
May 20, 3:20 PM EDT	Mesoscale Discussion	SPC	Bergen	85 min
May 20, 3:36 PM EDT	Mesoscale Discussion	SPC	Burlington, Camden, Essex, Gloucester, Hudson, Hunterdon and 9 more	84 min

Nearby

Tornado Watches in Pennsylvania, 2022 Tornado Watches in New Jersey, 2022 Tornado Watches in Maryland, 2022 Every tornado watch in 2022

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.