Alert archive / Vermont / Mesoscale Discussions in 2021
Mesoscale Discussion 1717
The Storm Prediction Center issued this mesoscale discussion at Sep 8, 2021, 6:30 PM EDT for Saratoga County, Washington County, New York; 8 counties in Vermont. It was in force for 90 min.
The area
The outline as issued.
The facts
- Issued
- Sep 8, 2021, 6:30 PM EDT (22:30 UTC)
- Expired
- Sep 8, 2021, 8:00 PM EDT
- In force
- 90 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
Counties Saratoga County, NY, Washington County, NY, Addison County, VT, Bennington County, VT, Lamoille County, VT, Orange County, VT, Orleans County, VT, Rutland County, VT, Washington County, VT, Windsor County, VT
The radar
The Burlington radar (KCXX), 87 km from the middle of the area, began a volume at 22:31 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, 10.5 hours before the alert went out and 132 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
- 1380 m above ground
- 0-6 km bulk shear
- 51 kt
- 0-1 km storm-relative helicity
- 241 m²/s²
- 0-3 km storm-relative helicity
- 235 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
234 ACUS11 KWNS 082231 SWOMCD SPC MCD 082230 VTZ000-NYZ000-090000- Mesoscale Discussion 1717 NWS Storm Prediction Center Norman OK 0530 PM CDT Wed Sep 08 2021 Areas affected...Northern Hudson Valley to VT Concerning...Severe potential...Watch unlikely Valid 082230Z - 090000Z Probability of Watch Issuance...20 percent SUMMARY...A few wind gusts are possible with a squall line this evening. DISCUSSION...Leading edge of large-scale forcing appears to be aiding upscale linear growth in thunderstorms this evening. Squall line has matured and currently extends from northwest VT-northern Hudson Valley-northeast PA. Northern extent of this squall line is advancing across an instability axis less than 1000 J/kg MLCAPE, with surface-3km lapse rates on the order of 7 C/km. Given the observed shear, organized updrafts are expected along this corridor but weaker buoyancy across New England should limit future intensification. At this time it appears gusty winds may be common but organized severe wind gusts are not currently anticipated. A severe thunderstorm watch is not currently warranted due to the marginal thermodynamic environment, but a watch is still possible farther southwest of this region. ..Darrow/Grams.. 09/08/2021 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BTV...ALY... LAT...LON 43027394 44987250 44707199 42947294 43027394
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 8, 4:40 AM EDT | Mesoscale Discussion | SPC | Erie, Niagara | 3 hr |
| Sep 8, 4:15 PM EDT | Mesoscale Discussion | SPC | Albany, Delaware, Greene, Orange, Schoharie, Sullivan and 1 more | 2 hr |
| Sep 8, 7:54 PM EDT | Severe Thunderstorm Watch | SPC | Columbia, Dutchess, Greene, Orange, Putnam, Rockland and 2 more | 4 hr |
Nearby
Mesoscale Discussions in Vermont, 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.