Alert archive / Nebraska / Mesoscale Discussions in 2021
Mesoscale Discussion 1597
The Storm Prediction Center issued this mesoscale discussion at Aug 24, 2021, 6:00 PM CDT for 28 counties in Nebraska. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 24, 2021, 6:00 PM CDT (23:00 UTC)
- Expired
- Aug 24, 2021, 8:00 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 5%
All 28 counties
Antelope County, NE, Blaine County, NE, Boone County, NE, Brown County, NE, Butler County, NE, Colfax County, NE, Custer County, NE, Garfield County, NE, Greeley County, NE, Holt County, NE, Howard County, NE, Knox County, NE, Logan County, NE, Loup County, NE, Madison County, NE, McPherson County, NE, Merrick County, NE, Nance County, NE, Pierce County, NE, Platte County, NE, Polk County, NE, Rock County, NE, Sherman County, NE, Stanton County, NE, Thomas County, NE, Valley County, NE, Wayne County, NE, Wheeler County, NE
The radar
The North Platte radar (KLNX), 101 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
N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 11.0 hours before the alert went out and 119 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
- 455 J/kg
- Mixed-layer CIN
- -346 J/kg
- Mixed-layer LCL
- 2180 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- -86 m²/s²
- 0-3 km storm-relative helicity
- 102 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
253
ACUS11 KWNS 242301
SWOMCD
SPC MCD 242300
NEZ000-250100-
Mesoscale Discussion 1597
NWS Storm Prediction Center Norman OK
0600 PM CDT Tue Aug 24 2021
Areas affected...Central Nebraska
Concerning...Severe potential...Watch unlikely
Valid 242300Z - 250100Z
Probability of Watch Issuance...5 percent
SUMMARY...A conditional severe risk exists across central Nebraska
this evening, but will be highly dependent on sustaining a mature
thunderstorm within a capped environment. Trends will be monitored,
but a watch is not likely at this time.
DISCUSSION...Latest GOES visible and IR imagery from central NE
shows a few convective towers and weak thunderstorms trying to
deepen along a cold front and within a diffuse warm frontal zone.
Despite the combined ascent from a weak upper-level impulse (noted
in water-vapor imagery over the state) and the frontal boundaries,
lingering inhibition is preventing storm maturation for the most
part. This has been exemplified by recent cells north of North
Platte, NE, one of which has only recently begun to mature thanks to
stronger forcing for ascent along a boundary collision within an
environment featuring favorable instability (up to 2500 J/kg MLCAPE)
and deep-layer shear values near 40 knots. The general expectation
is that the probability for additional convection will diminish
after 00z as diurnal cooling/stabilization takes place. However,
ongoing convection may intensify, or one or two new storms may
develop, within this region over the next hour. If this occurs,
storms may take on supercellular characteristics and pose a
wind/hail threat. Given the conditional and isolated nature of the
threat, a watch is not expected.
..Moore/Bunting.. 08/24/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...OAX...GID...LBF...
LAT...LON 41810135 42409998 42699883 42769761 42039693 41219700
40959791 40999914 41140031 41350111 41430137 41810135SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 23, 9:37 PM CDT | Mesoscale Discussion | SPC | Boyd, Keya Paha | 113 min |
Nearby
Mesoscale Discussions in Nebraska, 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.