Alert archive / Pennsylvania / Mesoscale Discussions in 2021
Mesoscale Discussion 1188
The Storm Prediction Center issued this mesoscale discussion at Jul 7, 2021, 7:11 PM EDT for 5 states. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 7, 2021, 7:11 PM EDT (23:11 UTC)
- Expired
- Jul 7, 2021, 9:15 PM EDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 344...345
All 61 counties
Berkshire County, MA, Bristol County, MA, Franklin County, MA, Hampden County, MA, Hampshire County, MA, Middlesex County, MA, Norfolk County, MA, Suffolk County, MA, Worcester County, MA, Bergen County, NJ, Morris County, NJ, Passaic County, NJ, Sussex County, NJ, Warren County, NJ, Albany County, NY, Allegany County, NY, Broome County, NY, Cattaraugus County, NY, Chemung County, NY, Chenango County, NY, Columbia County, NY, Delaware County, NY, Dutchess County, NY, Greene County, NY, Orange County, NY, Putnam County, NY, Rockland County, NY, Schuyler County, NY, Steuben County, NY, Sullivan County, NY, Tioga County, NY, Tompkins County, NY, Ulster County, NY, Westchester County, NY, Bradford County, PA, Cameron County, PA, Carbon County, PA, Centre County, PA, Clinton County, PA, Columbia County, PA, Elk County, PA, Lackawanna County, PA, Luzerne County, PA, Lycoming County, PA, McKean County, PA, Monroe County, PA, Montour County, PA, Northumberland County, PA, Pike County, PA, Potter County, PA, Sullivan County, PA, Susquehanna County, PA, Tioga County, PA, Union County, PA, Wayne County, PA, Wyoming County, PA, Bristol County, RI, Kent County, RI, Newport County, RI, Providence County, RI, Washington County, RI
The radar
The Albany radar (KENX), 82 km from the middle of the area, began a volume at 23:12 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
Albany, NY (KALY), launched 12:00Z, 11.2 hours before the alert went out and 102 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
- 18 J/kg
- Mixed-layer CIN
- -132 J/kg
- Mixed-layer LCL
- 923 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 49 m²/s²
- 0-3 km storm-relative helicity
- 64 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
884
ACUS11 KWNS 072312
SWOMCD
SPC MCD 072311
MAZ000-RIZ000-CTZ000-NYZ000-NJZ000-PAZ000-080115-
Mesoscale Discussion 1188
NWS Storm Prediction Center Norman OK
0611 PM CDT Wed Jul 07 2021
Areas affected...Northern Pennsylvania...Southern New
York...Southern New England
Concerning...Severe Thunderstorm Watch 344...345...
Valid 072311Z - 080115Z
The severe weather threat for Severe Thunderstorm Watch 344, 345
continues.
SUMMARY...A wind-damage threat will continue for several more hours
as cells track eastward across WW 344 and WW 345.
DISCUSSION...Surface analysis at 23Z shows a quasi-stationary front
located from near Lake Erie eastward across southern New York into
southern New England. To the south of the front, surface dewpoints
are in the upper 60s and lower 70s F. This is contributing to a
moderately unstable airmass, with the RAP estimating MLCAPE in the
1500 to 2000 J/kg range across the northern parts of WW 344 and 345.
In addition to the moist airmass, 0-6 km shear is measured near 35
kt on the Binghamton WSR-88D VWP. This appears representative of the
amount of shear across the northern part of the watches. The shear
combined with the instability will be sufficient for isolated
damaging wind gusts, associated with the more organized multicell
line segments. The threat should be greatest over the next couple
hours as low-level lapse rates remain steep. As the boundary layer
cools later this evening, the severe threat should become more
isolated.
..Broyles.. 07/07/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BOX...OKX...ALY...PHI...BGM...BUF...CTP...PBZ...
LAT...LON 42647337 42607124 42387092 41947078 41377099 41067203
40787520 40867806 41647918 41987931 42307898 42487682
42627359 42647337SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 7, 1:50 PM EDT | Mesoscale Discussion | SPC | 115 min | |
| Jul 7, 2:41 PM EDT | Severe Thunderstorm Watch | SPC | Greater Bridgeport Planning Region, Capitol Planning Region, Northwest Hills Planning Region, Lower Connecticut River Valley Planning Region, Naugatuck Valley Planning Region, Southeastern Connecticut Planning Region and 1 more | 10 hr |
| Jul 7, 4:48 PM EDT | Mesoscale Discussion | SPC | 87 min | |
| Jul 7, 3:31 PM EDT | Severe Thunderstorm Watch | SPC | Allegany, Cattaraugus, Chautauqua | 7 hr |
| Jul 7, 1:31 PM EDT | Severe Thunderstorm Watch | SPC | Crawford, Erie | 7 hr |
| Jul 7, 3:59 PM EDT | Mesoscale Discussion | SPC | Crawford, Erie | 91 min |
Nearby
Mesoscale Discussions in Pennsylvania, 2021Mesoscale Discussions in New York, 2021Mesoscale Discussions in Connecticut, 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.