Alert archive / New York / Mesoscale Discussions in 2021
Mesoscale Discussion 1952
The Storm Prediction Center issued this mesoscale discussion at Nov 28, 2021, 6:02 PM EST for 4 counties in New York; Erie County, McKean County, Warren County, Pennsylvania. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Nov 28, 2021, 6:02 PM EST (23:02 UTC)
- Expired
- Nov 28, 2021, 11:00 PM EST
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Heavy snow
Counties Allegany County, NY, Cattaraugus County, NY, Chautauqua County, NY, Steuben County, NY, Erie County, PA, McKean County, PA, Warren County, PA
The radar
The Buffalo radar (KBUF), 99 km from the middle of the area, began a volume at 23:03 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 nearest sounding before it
Buffalo Intl Airport, NY (KBUF), launched 12:00Z, 11.0 hours before the alert went out and 98 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
- 525 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 1 m²/s²
- 0-3 km storm-relative helicity
- 76 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
388
ACUS11 KWNS 282303
SWOMCD
SPC MCD 282302
PAZ000-NYZ000-290400-
Mesoscale Discussion 1952
NWS Storm Prediction Center Norman OK
0502 PM CST Sun Nov 28 2021
Areas affected...Portions of western NY and far northwestern PA
Concerning...Heavy snow
Valid 282302Z - 290400Z
SUMMARY...A narrow band of lake effect snow capable of producing
heavy snowfall, with rates of 2+ inches per hour, will continue
through the evening while gradually shifting southward.
DISCUSSION...Recent radar imagery from KBUF shows a narrow band of
heavy lake effect snowfall present over parts of southwestern NY
downstream from Lake Erie. This band is well organized, and will
likely persist through the evening while gradually shifting
southward into parts of far northwestern PA. Cold mid-level
temperatures associated with an upper trough/low over the Great
Lakes and seasonably warm water temperatures on Lake Erie are
supporting weak boundary-layer instability, with multiple lighting
flashes noted within the band over the past hour or so. The presence
of steep low/mid-level lapse rates, a saturated moisture profile,
and strong lift associated with the upper trough will help to
maintain this heavy snow band for the next several hours, with
snowfall rates in the band of 2+ inches per hour likely. As the
upper trough continues eastward this evening, low/mid-level winds
will gradually veer to a more northwesterly component versus
westerly, and the band should slowly shift southward accordingly
before eventually weakening late this evening/early Monday morning.
..Gleason.. 11/28/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BGM...BUF...CTP...CLE...
LAT...LON 42098028 42307958 42497890 42477787 42457715 42347710
41967757 41657826 41637914 41667986 41868034 41998040
42098028Nearby
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.