Alert archive / Pennsylvania / Mesoscale Discussions in 2021
Mesoscale Discussion 968
The Storm Prediction Center issued this mesoscale discussion at Jun 14, 2021, 3:25 PM EDT for Belmont County, Harrison County, Jefferson County, Ohio; 5 counties in Pennsylvania; Brooke County, Marshall County, Ohio County, West Virginia. It was in force for 95 min.
The area
The outline as issued.
The facts
- Issued
- Jun 14, 2021, 3:25 PM EDT (19:25 UTC)
- Expired
- Jun 14, 2021, 5:00 PM EDT
- In force
- 95 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 269
Counties Belmont County, OH, Harrison County, OH, Jefferson County, OH, Fayette County, PA, Greene County, PA, Somerset County, PA, Washington County, PA, Westmoreland County, PA, Brooke County, WV, Marshall County, WV, Ohio County, WV
The radar
The Pittsburgh radar (KPBZ), 56 km from the middle of the area, began a volume at 19:27 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
Pittsburgh, PA (KPIT), launched 12:00Z, 7.4 hours before the alert went out and 45 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
- 1684 m above ground
- 0-6 km bulk shear
- 51 kt
- 0-1 km storm-relative helicity
- 26 m²/s²
- 0-3 km storm-relative helicity
- 72 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
429
ACUS11 KWNS 141925
SWOMCD
SPC MCD 141925
PAZ000-WVZ000-OHZ000-142100-
Mesoscale Discussion 0968
NWS Storm Prediction Center Norman OK
0225 PM CDT Mon Jun 14 2021
Areas affected...Portions of far eastern OH...far northern WV...and
southwestern PA
Concerning...Severe Thunderstorm Watch 269...
Valid 141925Z - 142100Z
The severe weather threat for Severe Thunderstorm Watch 269
continues.
SUMMARY...The greatest severe hail and damaging wind threat should
focus across parts of far eastern OH, far northern West Virginia,
and southwestern Pennsylvania in the short term.
DISCUSSION...Two semi-discrete cells have recently strengthened just
to the south and southwest of Pittsburgh PA. Recent VWPs from KPBZ
show strengthening westerly winds in the 3-8 km layer, and 45-50 kt
of effective bulk shear will support continued storm organization.
The western cell has recently acquired supercell characteristics,
and large hail may occur in the short term. Around 500-1000 J/kg of
MLCAPE will be adequate to maintain current storm intensity.
Damaging winds may also occur as diurnal heating continues to
steepen low-level lapse rates to the south of a cold front. The
greatest severe hail and damaging wind threat should focus across
far eastern OH and far northern WV, where additional storms may form
along the cold front, and southwestern PA as the ongoing activity
spreads southeastward over the next couple of hours.
..Gleason.. 06/14/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...CTP...PBZ...
LAT...LON 39768082 39908112 40248121 40448103 40418061 40427984
40227908 39777893 39747946 39748052 39768082SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 14, 11:31 AM EDT | Mesoscale Discussion | SPC | Belmont, Carroll, Columbiana, Harrison, Jefferson, Mahoning | 89 min |
| Jun 14, 11:46 AM EDT | Severe Thunderstorm Watch | SPC | Belmont, Carroll, Columbiana, Guernsey, Harrison, Jefferson and 3 more | 6 hr |
| Jun 14, 1:40 PM EDT | Mesoscale Discussion | SPC | Adams, Berks, Bucks, Carbon, Chester, Columbia and 15 more | 3 hr |
| Jun 14, 2:06 PM EDT | Severe Thunderstorm Watch | SPC | Adams, Berks, Bucks, Carbon, Chester, Columbia and 22 more | 9 hr |
| Jun 14, 2:48 PM EDT | Mesoscale Discussion | SPC | Susquehanna | 2 hr |
| Jun 14, 6:18 PM EDT | Mesoscale Discussion | SPC | Berks, Bucks, Chester, Delaware, Lancaster, Lehigh and 3 more | 117 min |
| Jun 14, 3:55 PM EDT | Mesoscale Discussion | SPC | Berkeley, Grant, Hampshire, Hardy, Jefferson, Mineral and 2 more | 65 min |
| Jun 14, 3:59 PM EDT | Severe Thunderstorm Watch | SPC | Berkeley, Grant, Hampshire, Hardy, Jefferson, Mineral and 2 more | 6 hr |
| Jun 14, 4:52 PM EDT | Severe Thunderstorm Watch | SPC | Barbour, Doddridge, Harrison, Lewis, Marion, Marshall and 11 more | 6 hr |
| Jun 14, 7:37 PM EDT | Mesoscale Discussion | SPC | Barbour, Berkeley, Doddridge, Gilmer, Grant, Hampshire and 14 more | 113 min |
Nearby
Mesoscale Discussions in Pennsylvania, 2021Mesoscale Discussions in Ohio, 2021Mesoscale Discussions in West Virginia, 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.