Alert archive / Nebraska / Mesoscale Discussions in 2021
Mesoscale Discussion 2029
The Storm Prediction Center issued this mesoscale discussion at Dec 15, 2021, 2:30 PM CST for 5 counties in Kansas; 34 counties in Nebraska. It was in force for 90 min.
The area
The outline as issued.
The facts
- Issued
- Dec 15, 2021, 2:30 PM CST (20:30 UTC)
- Expired
- Dec 15, 2021, 4:00 PM CST
- In force
- 90 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 563
All 39 counties
Cloud County, KS, Marshall County, KS, Nemaha County, KS, Republic County, KS, Washington County, KS, Boone County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Colfax County, NE, Cuming County, NE, Dakota County, NE, Dodge County, NE, Douglas County, NE, Fillmore County, NE, Gage County, NE, Hamilton County, NE, Jefferson County, NE, Johnson County, NE, Lancaster County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Nemaha County, NE, Otoe County, NE, Pawnee County, NE, Pierce County, NE, Platte County, NE, Polk County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Stanton County, NE, Thayer County, NE, Thurston County, NE, Washington County, NE, Wayne County, NE, York County, NE
The radar
The Grand Island radar (KUEX), 105 km from the middle of the area, began a volume at 20:31 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Omaha, NE (KOAX), launched 12:00Z, 8.5 hours before the alert went out and 115 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
- 2165 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km storm-relative helicity
- 346 m²/s²
- 0-3 km storm-relative helicity
- 384 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
086
ACUS11 KWNS 152031
SWOMCD
SPC MCD 152030
NEZ000-KSZ000-152200-
Mesoscale Discussion 2029
NWS Storm Prediction Center Norman OK
0230 PM CST Wed Dec 15 2021
Areas affected...Portions of eastern NE and northeastern KS
Concerning...Tornado Watch 563...
Valid 152030Z - 152200Z
The severe weather threat for Tornado Watch 563 continues.
SUMMARY...The threat for a few tornadoes and widespread severe winds
of 60-85+ mph will spread east-northeastward across parts of eastern
Nebraska and northeastern KS through 4 PM CST.
DISCUSSION...A line of storms has quickly developed early this
afternoon across portions of north-central KS into south-central NE.
Multiple measured wind gusts of 60-85 mph have been recorded across
this region as the line moved through. 20Z mesoanalysis shows a
narrow corridor of 500-1000 J/kg of MLCAPE preceding the line across
northeastern KS into southeastern NE with minimal convective
inhibition noted due to the pronounced large-scale ascent preceding
a shortwave trough ejecting over the central Plains. A recent VWP
from KUEX shows a rapid increase in southwesterly flow in the 0-2 km
layer, with winds quickly increasing to around 70-80 kt just 1 km
AGL. Potential for these enhanced winds to reach the surface in
convective downdrafts will remain high in the short term across
northeastern KS and eastern NE as the line races east-northeastward
across this area around 50-60 kt. Widespread severe/damaging winds
of 60-85 mph will likely be the primary severe threat, with some
potential for even higher gusts given the strength of the low-level
flow. A few tornadoes with circulations embedded within the line
will also be a continued threat with the enhanced low-level shear
present (effective SRH around 200-300 m2/s2). A couple of these
circulations have already been observed in south-central NE, with at
least one CC minimum (likely TDS).
..Gleason.. 12/15/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FSD...OAX...TOP...GID...
LAT...LON 39339789 39729792 40479802 41429832 42399761 42439650
41669618 40029570 39609580 39289765 39339789SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 15, 12:28 PM CST | Mesoscale Discussion | SPC | Brown, Doniphan, Marshall, Nemaha, Republic, Washington | 2 hr |
| Dec 15, 1:23 PM CST | Tornado Watch | SPC | Brown, Clay, Cloud, Doniphan, Jackson, Jewell and 8 more | 7 hr |
| Dec 15, 2:29 PM CST | Mesoscale Discussion | SPC | Allen, Anderson, Atchison, Bourbon, Brown, Butler and 34 more | 2 hr |
| Dec 15, 3:18 PM CST | Severe Thunderstorm Watch | SPC | Allen, Anderson, Atchison, Butler, Chase, Chautauqua and 24 more | 5 hr |
| Dec 15, 3:55 PM CST | Mesoscale Discussion | SPC | Brown, Doniphan, Jackson, Nemaha, Pottawatomie | 95 min |
| Dec 15, 5:01 PM CST | Mesoscale Discussion | SPC | Allen, Anderson, Atchison, Bourbon, Brown, Butler and 28 more | 89 min |
| Dec 15, 5:30 PM CST | Mesoscale Discussion | SPC | Cherokee | 90 min |
| Dec 15, 4:05 PM CST | Mesoscale Discussion | SPC | Brown, Cherry, Hooker, Keya Paha, Thomas | 3 hr |
Nearby
Mesoscale Discussions in Nebraska, 2021Mesoscale Discussions in Kansas, 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.