Alert archive / Maryland / Mesoscale Discussions in 2020
Mesoscale Discussion 424
The Storm Prediction Center issued this mesoscale discussion at Apr 21, 2020, 12:23 PM EDT for 6 states. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 21, 2020, 12:23 PM EDT (16:23 UTC)
- Expired
- Apr 21, 2020, 2:30 PM EDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 40%
All 45 counties
Kent County, DE, New Castle County, DE, Anne Arundel County, MD, Baltimore County, MD, Calvert County, MD, Caroline County, MD, Cecil County, MD, Charles County, MD, City of Baltimore, MD, Dorchester County, MD, Harford County, MD, Howard County, MD, Kent County, MD, Prince George's County, MD, Queen Anne's County, MD, Saint Mary's County, MD, Talbot County, MD, Atlantic County, NJ, Burlington County, NJ, Camden County, NJ, Cumberland County, NJ, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Ocean County, NJ, Salem County, NJ, Somerset County, NJ, Union County, NJ, Warren County, NJ, Richmond County, NY, Bucks County, PA, Chester County, PA, Delaware County, PA, Lehigh County, PA, Montgomery County, PA, Northampton County, PA, Philadelphia County, PA, Arlington County, VA, City of Alexandria, VA, City of Fairfax, VA, City of Falls Church, VA, Fairfax County, VA, King George County, VA
The radar
The Dover AFB radar (KDOX), 95 km from the middle of the area, began a volume at 16:28 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 4.4 hours before the alert went out and 169 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1922 m above ground
- 0-6 km bulk shear
- 57 kt
- 0-1 km storm-relative helicity
- 197 m²/s²
- 0-3 km storm-relative helicity
- 207 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
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</html>SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 21, 1:27 PM EDT | Severe Thunderstorm Watch | SPC | Kent, New Castle, Sussex | 3 hr |
| Apr 21, 3:29 PM EDT | Mesoscale Discussion | SPC | Suffolk | 91 min |
Nearby
Mesoscale Discussions in Maryland, 2020Mesoscale Discussions in New Jersey, 2020Mesoscale Discussions in Pennsylvania, 2020Every mesoscale discussion 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.