Alert archive / Nebraska / Mesoscale Discussions in 2021
Mesoscale Discussion 1763
The Storm Prediction Center issued this mesoscale discussion at Sep 16, 2021, 7:57 PM CDT for 10 counties in Nebraska. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Sep 16, 2021, 7:57 PM CDT (00:57 UTC)
- Expired
- Sep 16, 2021, 10:00 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 40%
Counties Buffalo County, NE, Custer County, NE, Dawson County, NE, Keith County, NE, Lincoln County, NE, Logan County, NE, Loup County, NE, Perkins County, NE, Sherman County, NE, Valley County, NE
The radar
The North Platte radar (KLNX), 92 km from the middle of the area, began a volume at 00:58 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
N. Platte/Lee Bi, NE (KLBF), launched 00:00Z, 1.0 hours before the alert went out and 14 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
- 1601 J/kg
- Mixed-layer CIN
- -38 J/kg
- Mixed-layer LCL
- 2561 m above ground
- 0-6 km bulk shear
- 30 kt
- 0-1 km storm-relative helicity
- 106 m²/s²
- 0-3 km storm-relative helicity
- 153 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 4.7
The text
As transmitted.
355
ACUS11 KWNS 170058
SWOMCD
SPC MCD 170057
NEZ000-170300-
Mesoscale Discussion 1763
NWS Storm Prediction Center Norman OK
0757 PM CDT Thu Sep 16 2021
Areas affected...Central Nebraska
Concerning...Severe potential...Watch possible
Valid 170057Z - 170300Z
Probability of Watch Issuance...40 percent
SUMMARY...A growing cluster of storms moving out of southwest
Nebraska will likely persist for the next several hours and will
continue to pose a severe hail/wind threat. A watch may be needed to
address this potential.
DISCUSSION...A cluster of thunderstorms continues to mature as it
moves out of southwest NE and into central portions of the state.
Both severe hail and wind have occurred with this cluster over the
past hour, including a 67 mph wind report at KOGA near Ogallala, NE.
The 00z North Platte sounding captures the downstream environment
ahead of this cluster well and features nearly 2300 J/kg MUCAPE with
minimal inhibition and steep mid-level lapse rates. Although
effective bulk shear was only near 30 knots, increasing flow in the
mid and upper levels over the coming hours may augment bulk shear
values to near 40 knots. Isentropic ascent in the vicinity of the
terminus of the nocturnal jet will maintain this cluster, and the
attendant hail/wind risk, at least for the next 2-4 hours as they
move into central NE. A watch may be needed to address this concern.
..Moore/Edwards.. 09/17/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GID...LBF...
LAT...LON 41060202 41470178 41830023 41949920 41519850 41119853
40779893 40600019 40570149 40640185 41060202SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 16, 7:15 PM CDT | Mesoscale Discussion | SPC | Blaine, Box Butte, Boyd, Brown, Cherry, Garden and 10 more | 2 hr |
| Sep 16, 8:16 PM CDT | Severe Thunderstorm Watch | SPC | Blaine, Boyd, Brown, Cherry, Custer, Dawson and 16 more | 6 hr |
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.