Alert archive / New York / Mesoscale Discussions in 2021
Mesoscale Discussion 1497
The Storm Prediction Center issued this mesoscale discussion at Aug 12, 2021, 11:03 AM EDT for 25 counties in New York; Susquehanna County, Pennsylvania; 13 counties in Vermont. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 12, 2021, 11:03 AM EDT (15:03 UTC)
- Expired
- Aug 12, 2021, 1:30 PM EDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 60%
All 39 counties
Albany County, NY, Broome County, NY, Chenango County, NY, Clinton County, NY, Cortland County, NY, Delaware County, NY, Essex County, NY, Franklin County, NY, Fulton County, NY, Greene County, NY, Hamilton County, NY, Herkimer County, NY, Lewis County, NY, Madison County, NY, Montgomery County, NY, Oneida County, NY, Otsego County, NY, Rensselaer County, NY, Saratoga County, NY, Schenectady County, NY, Schoharie County, NY, St. Lawrence County, NY, Tioga County, NY, Warren County, NY, Washington County, NY, Susquehanna County, PA, Addison County, VT, Bennington County, VT, Caledonia County, VT, Chittenden County, VT, Franklin County, VT, Grand Isle County, VT, Lamoille County, VT, Orange County, VT, Orleans County, VT, Rutland County, VT, Washington County, VT, Windham County, VT, Windsor County, VT
The radar
The Ft Drum radar (KTYX), 91 km from the middle of the area, began a volume at 15:03 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, 3.1 hours before the alert went out and 103 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
- 58 J/kg
- Mixed-layer CIN
- -212 J/kg
- Mixed-layer LCL
- 1178 m above ground
- 0-6 km bulk shear
- 22 kt
- 0-1 km storm-relative helicity
- 62 m²/s²
- 0-3 km storm-relative helicity
- 56 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
054
ACUS11 KWNS 121504
SWOMCD
SPC MCD 121503
NHZ000-VTZ000-MAZ000-NYZ000-PAZ000-121730-
Mesoscale Discussion 1497
NWS Storm Prediction Center Norman OK
1003 AM CDT Thu Aug 12 2021
Areas affected...northern and central NY...VT...northern PA
Concerning...Severe potential...Watch possible
Valid 121503Z - 121730Z
Probability of Watch Issuance...60 percent
SUMMARY...A severe thunderstorm watch will most likely be needed by
the early afternoon timeframe as storms develop/intensify.
Strong/severe gusts (50-65 mph) will be possible with the more
intense downdrafts.
DISCUSSION...Visible-satellite imagery shows an MCV near the eastern
shore of Lake Ontario quickly moving northeast and paralleling the
international border. To the east through south of the mid-level
feature, heating is occurring under mostly clear skies to areas of
stratocumulus. Surface conditions as of 1050am on the NY Mesonet
show temperatures ranging from the mid 70s beneath the cloud patches
to lower 80s. Dewpoints range from 69-74 deg F.
The Fort Drum, NY (KTYX) and Buffalo, NY (KBUF) VAD data show a belt
of flow 35-50 kt around 3 km AGL. The VAD data is similar to the
strength of flow (40-50 kt in the 850-700 mb layer) sampled by the
12z Buffalo, NY raob.
As the airmass continues to destabilize and yield moderate buoyancy
by midday (1000-2000 J/kg MLCAPE), expecting storms to develop and
increase in coverage through mid afternoon across central/northern
NY. Clusters of strong to severe storms are possible resulting in
damaging/locally severe gusts (50-65 mph). Scattered wind damage
will be possible with the more intense water-loaded downdrafts.
..Smith/Thompson.. 08/12/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GYX...BTV...ALY...BGM...BUF...
LAT...LON 41917681 43237592 44467577 45007480 44967182 43177231
41977452 41557579 41917681SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 12, 1:42 PM EDT | Severe Thunderstorm Watch | SPC | Albany, Broome, Chenango, Columbia, Cortland, Delaware and 17 more | 6 hr |
| Aug 12, 12:19 PM EDT | Mesoscale Discussion | SPC | Allegheny, Armstrong, Blair, Butler, Cambria, Cameron and 20 more | 116 min |
| Aug 12, 1:11 PM EDT | Severe Thunderstorm Watch | SPC | Armstrong, Bedford, Blair, Cambria, Cameron, Centre and 27 more | 9 hr |
| Aug 12, 3:17 PM EDT | Mesoscale Discussion | SPC | Allegheny, Beaver, Butler, Crawford, Lawrence, Mercer and 1 more | 58 min |
| Aug 12, 3:48 PM EDT | Severe Thunderstorm Watch | SPC | Allegheny, Armstrong, Beaver, Butler, Clarion, Crawford and 11 more | 6 hr |
| Aug 12, 6:22 PM EDT | Mesoscale Discussion | SPC | Allegheny, Armstrong, Beaver, Blair, Butler, Cambria and 21 more | 83 min |
Nearby
Mesoscale Discussions in New York, 2021Mesoscale Discussions in Vermont, 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.