Alert archive / Pennsylvania / Mesoscale Discussions in 2018
Mesoscale Discussion 392
The Storm Prediction Center issued this mesoscale discussion at May 12, 2018, 3:59 PM EDT for 4 states. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- May 12, 2018, 3:59 PM EDT (19:59 UTC)
- Expired
- May 12, 2018, 6:30 PM EDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 95%
All 29 counties
Kent County, DE, New Castle County, DE, Baltimore County, MD, Carroll County, MD, Cecil County, MD, City of Baltimore, MD, Harford County, MD, Howard County, MD, Kent County, MD, Montgomery County, MD, Queen Anne's County, MD, Atlantic County, NJ, Burlington County, NJ, Camden County, NJ, Cape May County, NJ, Cumberland County, NJ, Gloucester County, NJ, Ocean County, NJ, Salem County, NJ, Berks County, PA, Bucks County, PA, Chester County, PA, Dauphin County, PA, Delaware County, PA, Lancaster County, PA, Lebanon County, PA, Montgomery County, PA, Philadelphia County, PA, York County, PA
The radar
The Dover AFB radar (KDOX), 92 km from the middle of the area, began a volume at 19:56 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, 8.0 hours before the alert went out and 165 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
- 1390 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 178 m²/s²
- 0-3 km storm-relative helicity
- 201 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 |
|---|---|---|---|---|
| May 12, 4:58 PM EDT | Tornado Watch | SPC | Kent, New Castle, Sussex | 5 hr |
| May 12, 7:16 PM EDT | Mesoscale Discussion | SPC | Kent, New Castle, Sussex | 59 min |
| May 12, 1:51 PM EDT | Mesoscale Discussion | SPC | Allegany, Garrett | 2 hr |
| May 12, 2:47 PM EDT | Severe Thunderstorm Watch | SPC | Allegany, Calvert, Charles, Frederick, Garrett, Montgomery and 3 more | 8 hr |
| May 12, 5:05 PM EDT | Mesoscale Discussion | SPC | Allegany, Frederick, Garrett, Washington | 115 min |
Nearby
Mesoscale Discussions in Pennsylvania, 2018Mesoscale Discussions in Maryland, 2018Mesoscale Discussions in New Jersey, 2018Every mesoscale discussion in 2018
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.