Alert archive / Pennsylvania / Mesoscale Discussions in 2021
Mesoscale Discussion 960
The Storm Prediction Center issued this mesoscale discussion at Jun 13, 2021, 7:21 PM EDT for 26 counties in Pennsylvania. It was in force for 84 min.
The area
The outline as issued.
The facts
- Issued
- Jun 13, 2021, 7:21 PM EDT (23:21 UTC)
- Expired
- Jun 13, 2021, 8:45 PM EDT
- In force
- 84 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 266
All 26 counties
Blair County, PA, Bradford County, PA, Cambria County, PA, Cameron County, PA, Carbon County, PA, Centre County, PA, Clearfield County, PA, Clinton County, PA, Columbia County, PA, Elk County, PA, Huntingdon County, PA, Juniata County, PA, Luzerne County, PA, Lycoming County, PA, McKean County, PA, Mifflin County, PA, Montour County, PA, Northumberland County, PA, Potter County, PA, Schuylkill County, PA, Snyder County, PA, Sullivan County, PA, Susquehanna County, PA, Tioga County, PA, Union County, PA, Wyoming County, PA
The radar
The State College radar (KCCX), 58 km from the middle of the area, began a volume at 23:24 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
Buffalo Intl Airport, NY (KBUF), launched 12:00Z, 11.4 hours before the alert went out and 196 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
- 2252 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- -7 m²/s²
- 0-3 km storm-relative helicity
- 32 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
375 ACUS11 KWNS 132321 SWOMCD SPC MCD 132321 PAZ000-NYZ000-140045- Mesoscale Discussion 0960 NWS Storm Prediction Center Norman OK 0621 PM CDT Sun Jun 13 2021 Areas affected...Pennsylvania Concerning...Severe Thunderstorm Watch 266... Valid 132321Z - 140045Z The severe weather threat for Severe Thunderstorm Watch 266 continues. SUMMARY...Severe threat continues across mainly the western and central portions of ww266. DISCUSSION...Scattered robust convection has struggled to spread east of the higher terrain. This is likely partly due to much steeper lapse-rate environment extending across western NY, south into Clearfield County PA. Primary updraft feed is from this steeper lapse-rate plume and given the slow forward propagation, new updrafts may continue to develop in proximity to higher buoyancy. For these reasons, western and central portions of ww266 may remain most active. ..Darrow.. 06/13/2021 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PHI...BGM...BUF...CTP...PBZ... LAT...LON 41907896 42157562 40547562 40327896 41907896
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 13, 12:13 PM EDT | Mesoscale Discussion | SPC | Allegheny, Armstrong, Beaver, Bedford, Butler, Cambria and 8 more | 2 hr |
| Jun 13, 12:50 PM EDT | Severe Thunderstorm Watch | SPC | Allegheny, Armstrong, Beaver, Butler, Clarion, Fayette and 9 more | 7 hr |
| Jun 13, 2:38 PM EDT | Mesoscale Discussion | SPC | Blair, Bradford, Cambria, Cameron, Centre, Clearfield and 20 more | 2 hr |
| Jun 13, 3:26 PM EDT | Mesoscale Discussion | SPC | Allegheny, Armstrong, Beaver, Butler, Clarion, Fayette and 10 more | 94 min |
| Jun 13, 3:26 PM EDT | Severe Thunderstorm Watch | SPC | Blair, Bradford, Cambria, Cameron, Centre, Clearfield and 20 more | 7 hr |
| Jun 13, 4:56 PM EDT | Mesoscale Discussion | SPC | Blair, Bradford, Cambria, Cameron, Centre, Clarion and 25 more | 94 min |
Nearby
Mesoscale Discussions in Pennsylvania, 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.