Alert archive / New York / Mesoscale Discussions in 2021
Mesoscale Discussion 1513
The Storm Prediction Center issued this mesoscale discussion at Aug 13, 2021, 2:48 PM EDT for 25 counties in New York; 8 counties in Pennsylvania. It was in force for 87 min.
The area
The outline as issued.
The facts
- Issued
- Aug 13, 2021, 2:48 PM EDT (18:48 UTC)
- Expired
- Aug 13, 2021, 4:15 PM EDT
- In force
- 87 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 40%
All 33 counties
Broome County, NY, Cayuga County, NY, Chemung County, NY, Chenango County, NY, Cortland County, NY, Essex County, NY, Fulton County, NY, Hamilton County, NY, Herkimer County, NY, Lewis County, NY, Madison County, NY, Montgomery County, NY, Oneida County, NY, Onondaga County, NY, Oswego County, NY, Otsego County, NY, Saratoga County, NY, Schuyler County, NY, Seneca County, NY, Steuben County, NY, Tioga County, NY, Tompkins County, NY, Warren County, NY, Washington County, NY, Yates County, NY, Bradford County, PA, Cameron County, PA, Clinton County, PA, Lycoming County, PA, Potter County, PA, Sullivan County, PA, Susquehanna County, PA, Tioga County, PA
The radar
The Binghamton radar (KBGM), 55 km from the middle of the area, began a volume at 18:48 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
Albany, NY (KALY), launched 12:00Z, 6.8 hours before the alert went out and 183 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
- 239 J/kg
- Mixed-layer CIN
- -124 J/kg
- Mixed-layer LCL
- 879 m above ground
- 0-6 km bulk shear
- 16 kt
- 0-1 km storm-relative helicity
- 31 m²/s²
- 0-3 km storm-relative helicity
- 27 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.2
The text
As transmitted.
792
ACUS11 KWNS 131849
SWOMCD
SPC MCD 131848
VTZ000-NYZ000-PAZ000-132015-
Mesoscale Discussion 1513
NWS Storm Prediction Center Norman OK
0148 PM CDT Fri Aug 13 2021
Areas affected...north-central PA...central and northern parts of NY
Concerning...Severe potential...Watch possible
Valid 131848Z - 132015Z
Probability of Watch Issuance...40 percent
SUMMARY...Isolated to widely scattered damaging gusts are possible
this afternoon from north-central PA northeastward into central NY.
It is uncertain whether a severe thunderstorm watch is needed for
portions of this area.
DISCUSSION...Visible satellite imagery shows an MCV moving east
across northwest PA near the NY/PA border with an agitated cumulus
field ahead of the mid-level impulse. A couple of thunderstorms
have recently developed over north-central PA and over parts of
central NY. NY Mesonet observations show temperatures generally in
the mid to upper 80s with lower 70s dewpoints. NAM forecast
soundings suggest 2500-3000 J/kg MLCAPE is present based on current
surface observations, whereas RAP soundings appear too dry at the
surface and are under-representing buoyancy. Additionally, forecast
soundings show a modest increase of flow from the surface to the mid
levels. The 30-kt 500 mb flow is resulting in effective shear
supporting organized multicells and perhaps brief/weak supercell
structure. Expecting storm coverage to increase over north-central
PA into southern NY east of the Finger Lakes through the late
afternoon in association with the MCV. Strong to locally severe
gusts (50-60 mph) are possible with the stronger storms.
..Smith/Hart.. 08/13/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BTV...ALY...BGM...BUF...CTP...
LAT...LON 41857839 43597634 44507446 44377360 43917328 43297338
41137693 41017765 41367826 41857839SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 13, 3:29 PM EDT | Severe Thunderstorm Watch | SPC | Albany, Broome, Cayuga, Chemung, Chenango, Columbia and 28 more | 7 hr |
| Aug 13, 7:14 PM EDT | Mesoscale Discussion | SPC | Albany, Broome, Cayuga, Chemung, Chenango, Columbia and 29 more | 61 min |
| Aug 12, 10:08 PM EDT | Mesoscale Discussion | SPC | Berks, Bucks, Carbon, Chester, Columbia, Cumberland and 22 more | 67 min |
| Aug 13, 12:33 PM EDT | Mesoscale Discussion | SPC | Adams, Cumberland, Dauphin, Franklin, Fulton, Lancaster and 3 more | 87 min |
| Aug 13, 1:11 PM EDT | Severe Thunderstorm Watch | SPC | Adams, Berks, Chester, Cumberland, Dauphin, Franklin and 6 more | 7 hr |
| Aug 13, 4:46 PM EDT | Severe Thunderstorm Watch | SPC | Allegheny, Armstrong, Beaver, Butler, Clarion, Fayette and 9 more | 5 hr |
| Aug 13, 4:48 PM EDT | Mesoscale Discussion | SPC | Chester | 87 min |
| Aug 13, 7:49 PM EDT | Mesoscale Discussion | SPC | Allegheny, Armstrong, Beaver, Butler, Cambria, Clarion and 13 more | 56 min |
Nearby
Mesoscale Discussions in New York, 2021Mesoscale 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.