Alert archive / Pennsylvania / Mesoscale Discussions in 2026

Mesoscale Discussion 2

January 1, 20264 states

The Storm Prediction Center issued this mesoscale discussion at Jan 1, 2026, 3:00 AM EST for 4 states. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: Jan 1, 2026, 3:00 AM EST (08:00 UTC)
Expired: Jan 1, 2026, 6:30 AM EST
In force: 4 hr
Issued by: the Storm Prediction Center
Concerning: Snow squall

All 34 counties

Baltimore County, MD, Carroll County, MD, Frederick County, MD, Washington County, MD, Bergen County, NJ, Essex County, NJ, Hunterdon County, NJ, Morris County, NJ, Passaic County, NJ, Somerset County, NJ, Sussex County, NJ, Union County, NJ, Warren County, NJ, Dutchess County, NY, Orange County, NY, Putnam County, NY, Rockland County, NY, Sullivan County, NY, Ulster County, NY, Westchester County, NY, Adams County, PA, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Lancaster County, PA, Lebanon County, PA, Lehigh County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA, Pike County, PA, Schuylkill County, PA, York County, PA

The radar

The Philadelphia radar (KDIX), 115 km from the middle of the area, began a volume at 08:02 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 nearest sounding before it

Brookhaven, NY (KOKX), launched 00:00Z, 8.0 hours before the alert went out and 212 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1256 m above ground
0-6 km bulk shear: 62 kt
0-1 km storm-relative helicity: 143 m²/s²
0-3 km storm-relative helicity: 261 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 31, 11:26 PM EST	Mesoscale Discussion	SPC	Allegany, Garrett	4 hr

Nearby

Mesoscale Discussions in Pennsylvania, 2026 Mesoscale Discussions in New Jersey, 2026 Mesoscale Discussions in New York, 2026 Every mesoscale discussion in 2026

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.