Alert archive / North Carolina / Mesoscale Discussions in 2021
Mesoscale Discussion 61
The Storm Prediction Center issued this mesoscale discussion at Feb 6, 2021, 10:08 PM EST for 4 counties in Georgia; 9 counties in North Carolina; 6 counties in South Carolina. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Feb 6, 2021, 10:08 PM EST (03:08 UTC)
- Expired
- Feb 7, 2021, 2:15 AM EST
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Heavy snow
Counties Franklin County, GA, Hart County, GA, Rabun County, GA, Stephens County, GA, Buncombe County, NC, Burke County, NC, Cleveland County, NC, Henderson County, NC, Jackson County, NC, McDowell County, NC, Polk County, NC, Rutherford County, NC, Transylvania County, NC, Anderson County, SC, Cherokee County, SC, Greenville County, SC, Oconee County, SC, Pickens County, SC, Spartanburg County, SC
The radar
The Greer radar (KGSP), 19 km from the middle of the area, began a volume at 03:12 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
Greensboro/Hi Pt, NC (KGSO), launched 00:00Z, 3.1 hours before the alert went out and 254 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
- 2474 m above ground
- 0-6 km bulk shear
- 78 kt
- 0-1 km storm-relative helicity
- 69 m²/s²
- 0-3 km storm-relative helicity
- 14 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
953
ACUS11 KWNS 070308
SWOMCD
SPC MCD 070308
NCZ000-SCZ000-GAZ000-070715-
Mesoscale Discussion 0061
NWS Storm Prediction Center Norman OK
0908 PM CST Sat Feb 06 2021
Areas affected...Southern Appalachians and Vicinity
Concerning...Heavy snow
Valid 070308Z - 070715Z
SUMMARY...Heavy snow, with rates exceeding 1 in/hr, expected this
evening over the southern Appalachians, perhaps changing to freezing
rain in a few spots after 04z-05z.
DISCUSSION...Recent mesoanalysis shows an amplifying mid-level
short-wave trough approaching the region, with strong/broad
southwesterly deep-layer flow and large-scale ascent occurring ahead
of this system. Regional radar shows a broad precipitation shield
that continues to expand and overspread the area. As low-levels of
the atmosphere continue to saturate, surface temperatures have
fallen several degrees in the past few hours, with areas in/near the
higher terrain falling below freezing. Consequently, the
precipitation type across eastern portions of the Carolinas has
switched to snow, with some locations reporting moderate snow.
As the amplifying short-wave continues its approach, several more
hours of broad ascent and renewed precipitation development is
expected. Presently, it appears frozen precipitation types should be
confined to the higher terrain regions in proximity to the southern
Appalachians. Snowfall rates near 1 in/hr can be expected initially.
Forecast soundings indicate very strong low-level warm-air advection
(50 kt flow in the 750-700 mb layer) that may result in a period of
mixed precipitation. Should this occur, some locations could also
experience freezing-rain rates near 0.06 in/3-hr after around
04z-05z.
..Karstens.. 02/07/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GSP...
LAT...LON 34588210 34238274 34358324 34758350 35558297 36108184
35838125 34988163 34588210Nearby
Mesoscale Discussions in North Carolina, 2021Mesoscale Discussions in South Carolina, 2021Mesoscale Discussions in Georgia, 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.