Alert archive / Pennsylvania / Mesoscale Discussions in 2021
Mesoscale Discussion 745
The Storm Prediction Center issued this mesoscale discussion at May 26, 2021, 12:16 PM EDT for 5 states. It was in force for 119 min.
The area
The outline as issued.
The facts
- Issued
- May 26, 2021, 12:16 PM EDT (16:16 UTC)
- Expired
- May 26, 2021, 2:15 PM EDT
- In force
- 119 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch likely
- Chance of a watch
- 80%
All 103 counties
Albany County, NY, Allegany County, NY, Broome County, NY, Cattaraugus County, NY, Cayuga County, NY, Chautauqua County, NY, Chemung County, NY, Chenango County, NY, Cortland County, NY, Delaware County, NY, Erie County, NY, Essex County, NY, Fulton County, NY, Genesee County, NY, Greene County, NY, Hamilton County, NY, Herkimer County, NY, Livingston County, NY, Madison County, NY, Montgomery County, NY, Oneida County, NY, Onondaga County, NY, Ontario County, NY, Otsego County, NY, Rensselaer County, NY, Saratoga County, NY, Schenectady County, NY, Schoharie County, NY, Schuyler County, NY, Seneca County, NY, Steuben County, NY, Tioga County, NY, Tompkins County, NY, Warren County, NY, Washington County, NY, Wayne County, NY, Wyoming County, NY, Yates County, NY, Belmont County, OH, Carroll County, OH, Columbiana County, OH, Geauga County, OH, Guernsey County, OH, Harrison County, OH, Jefferson County, OH, Mahoning County, OH, Portage County, OH, Stark County, OH, Trumbull County, OH, Tuscarawas County, OH, Allegheny County, PA, Armstrong County, PA, Beaver County, PA, Blair County, PA, Bradford County, PA, Butler County, PA, Cambria County, PA, Cameron County, PA, Centre County, PA, Clarion County, PA, Clearfield County, PA, Clinton County, PA, Columbia County, PA, Crawford County, PA, Elk County, PA, Erie County, PA, Fayette County, PA, Forest County, PA, Greene County, PA, Huntingdon County, PA, Indiana County, PA, Jefferson County, PA, Juniata County, PA, Lackawanna County, PA, Lawrence County, PA, Luzerne County, PA, Lycoming County, PA, McKean County, PA, Mercer County, PA, Mifflin County, PA, Montour County, PA, Northumberland County, PA, Potter County, PA, Snyder County, PA, Somerset County, PA, Sullivan County, PA, Susquehanna County, PA, Tioga County, PA, Union County, PA, Venango County, PA, Warren County, PA, Washington County, PA, Wayne County, PA, Westmoreland County, PA, Wyoming County, PA, Addison County, VT, Bennington County, VT, Rutland County, VT, Washington County, VT, Windsor County, VT, Brooke County, WV, Hancock County, WV, Ohio County, WV
The radar
The Binghamton radar (KBGM), 62 km from the middle of the area, began a volume at 16:16 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
Buffalo Intl Airport, NY (KBUF), launched 12:00Z, 4.3 hours before the alert went out and 175 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
- 26 J/kg
- Mixed-layer CIN
- -100 J/kg
- Mixed-layer LCL
- 1679 m above ground
- 0-6 km bulk shear
- 28 kt
- 0-1 km storm-relative helicity
- 105 m²/s²
- 0-3 km storm-relative helicity
- 127 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
408
ACUS11 KWNS 261616
SWOMCD
SPC MCD 261616
VTZ000-MAZ000-NYZ000-PAZ000-WVZ000-OHZ000-261815-
Mesoscale Discussion 0745
NWS Storm Prediction Center Norman OK
1116 AM CDT Wed May 26 2021
Areas affected...eastern Ohio/western Pennsylvania northeast to
Vermont
Concerning...Severe potential...Watch likely
Valid 261616Z - 261815Z
Probability of Watch Issuance...80 percent
SUMMARY...A continued/gradual increase in convective coverage and
intensity is expected across the upper Ohio Valley/central and
northern Appalachians this afternoon. As potential for locally
stronger wind gusts increases, WW issuance will likely be required.
DISCUSSION...Scattered to broken cloud cover across much of the
Northeast is facilitating diurnal heating/gradual destabilization
across the discussion area, with pre-frontal convection now
initiating from upstate NY southwestward into western PA at this
time. As the upper short-wave trough advances across eastern Canada
and the Great Lakes with time, large-scale ascent will support
further increases in storm coverage/intensity with time. Aided by
moderate/roughly unidirectional west-southwesterly flow through a
deep layer, eventual upscale growth of storms into small bands, and
some cold pool development/interaction, is expected -- along with
attendant/local increases in risk for damaging winds. Given this
potential, WW issuance will likely be required.
..Goss/Hart.. 05/26/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BTV...ALY...BGM...BUF...CTP...PBZ...CLE...
LAT...LON 44377228 44397360 43237663 43257723 42957842 41588122
40098176 39808027 40057844 41107577 43077261 44377228SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 26, 12:59 PM EDT | Severe Thunderstorm Watch | SPC | Albany, Broome, Chemung, Chenango, Columbia, Cortland and 23 more | 7 hr |
| May 26, 2:07 PM EDT | Mesoscale Discussion | SPC | Albany, Chenango, Cortland, Fulton, Greene, Madison and 6 more | 83 min |
| May 26, 2:48 PM EDT | Severe Thunderstorm Watch | SPC | Bronx, Kings, New York, Orange, Putnam, Queens and 3 more | 7 hr |
| May 26, 4:41 PM EDT | Mesoscale Discussion | SPC | Albany, Bronx, Columbia, Dutchess, Greene, Kings and 12 more | 64 min |
| May 26, 6:34 PM EDT | Mesoscale Discussion | SPC | Bronx, Kings, New York, Richmond | 116 min |
| May 26, 1:21 PM EDT | Mesoscale Discussion | SPC | Berkeley, Jefferson | 84 min |
Nearby
Mesoscale Discussions in Pennsylvania, 2021Mesoscale Discussions in New York, 2021Mesoscale Discussions in Ohio, 2021Every mesoscale discussion in 2021
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.