Alert archive / Pennsylvania / Mesoscale Discussions in 2021
Mesoscale Discussion 1050
The Storm Prediction Center issued this mesoscale discussion at Jun 21, 2021, 3:47 PM EDT for 6 counties in New York; 12 counties in Pennsylvania. It was in force for 58 min.
The area
The outline as issued.
The facts
- Issued
- Jun 21, 2021, 3:47 PM EDT (19:47 UTC)
- Expired
- Jun 21, 2021, 4:45 PM EDT
- In force
- 58 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 299
Counties Allegany County, NY, Livingston County, NY, Ontario County, NY, Steuben County, NY, Wayne County, NY, Yates County, NY, Allegheny County, PA, Armstrong County, PA, Cambria County, PA, Cameron County, PA, Clearfield County, PA, Elk County, PA, Indiana County, PA, Jefferson County, PA, McKean County, PA, Potter County, PA, Washington County, PA, Westmoreland County, PA
The radar
The Buffalo radar (KBUF), 111 km from the middle of the area, began a volume at 19:50 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, 7.8 hours before the alert went out and 108 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
- 9 J/kg
- Mixed-layer CIN
- -284 J/kg
- Mixed-layer LCL
- 1192 m above ground
- 0-6 km bulk shear
- 46 kt
- 0-1 km storm-relative helicity
- 257 m²/s²
- 0-3 km storm-relative helicity
- 304 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
651 ACUS11 KWNS 211947 SWOMCD SPC MCD 211947 NYZ000-PAZ000-212045- Mesoscale Discussion 1050 NWS Storm Prediction Center Norman OK 0247 PM CDT Mon Jun 21 2021 Areas affected...southwest into north-central PA...western NY Concerning...Severe Thunderstorm Watch 299... Valid 211947Z - 212045Z The severe weather threat for Severe Thunderstorm Watch 299 continues. SUMMARY...Widely scattered strong to locally severe gusts (50-70 mph) are possible with the more intense thunderstorms as several linear segments/clusters move east towards the NY Finger Lakes southward into west-central PA over the next 1-2 hours. DISCUSSION...Radar mosaic shows several linear segments and thunderstorm clusters moving east from the south shore of Lake Ontario south-southwestward to the Pittsburgh, PA metro. A moist and moderately unstable airmass ahead of the approaching thunderstorm activity will continue to support widely scattered strong gusts with isolated occurrences of gusts 60-70 mph. The Pittsburgh, PA 88D VAD shows 40-kt westerly flow at 3 km ARL. The Ithaca, NY ASOS recently measured a 46-kt gust at 1932 UTC (with an isolated storm to the east) and a NY Mesonet site in Wyoming County, NY measured a 49 mph gust with the squall line. Some of the stronger downdrafts will be capable of channeling this higher momentum to the surface in the form of strong to locally severe gusts through the remainder of the afternoon, as the activity moves east across western NY and western PA. ..Smith.. 06/21/2021 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BGM...BUF...CTP...PBZ... LAT...LON 43347751 42107838 40158047 39847917 43367646 43347751
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 21, 11:59 AM EDT | Mesoscale Discussion | SPC | Cattaraugus, Chautauqua | 91 min |
| Jun 21, 12:31 PM EDT | Mesoscale Discussion | SPC | Clinton, Essex, Franklin, Fulton, Hamilton, Herkimer and 12 more | 89 min |
| Jun 21, 12:31 PM EDT | Severe Thunderstorm Watch | SPC | Allegany, Cattaraugus, Cayuga, Chautauqua, Erie, Genesee and 14 more | 7 hr |
| Jun 21, 1:11 PM EDT | Severe Thunderstorm Watch | SPC | Broome, Chemung, Chenango, Clinton, Cortland, Essex and 14 more | 10 hr |
| Jun 21, 3:35 PM EDT | Mesoscale Discussion | SPC | Clinton, Essex, Franklin, Fulton, Hamilton, Herkimer and 7 more | 85 min |
| Jun 21, 3:45 PM EDT | Severe Thunderstorm Watch | SPC | Albany, Columbia, Delaware, Dutchess, Greene, Otsego and 5 more | 7 hr |
| Jun 21, 4:33 PM EDT | Severe Thunderstorm Watch | SPC | Orange | 6 hr |
| Jun 21, 6:50 PM EDT | Mesoscale Discussion | SPC | Albany, Broome, Chenango, Columbia, Cortland, Delaware and 23 more | 55 min |
| Jun 21, 1:51 PM EDT | Mesoscale Discussion | SPC | Adams, Bedford, Berks, Blair, Bradford, Bucks and 37 more | 114 min |
| Jun 21, 2:20 PM EDT | Severe Thunderstorm Watch | SPC | Adams, Bedford, Blair, Centre, Clinton, Columbia and 19 more | 6 hr |
| Jun 21, 6:15 PM EDT | Mesoscale Discussion | SPC | Bucks, Chester, Delaware, Lancaster, Montgomery, Philadelphia | 60 min |
Nearby
Mesoscale Discussions in Pennsylvania, 2021Mesoscale Discussions in New York, 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.