Alert archive / Nebraska / Mesoscale Discussions in 2021
Mesoscale Discussion 1599
The Storm Prediction Center issued this mesoscale discussion at Aug 24, 2021, 11:18 PM CDT for 7 counties in Nebraska. It was in force for 117 min.
The area
The outline as issued.
The facts
- Issued
- Aug 24, 2021, 11:18 PM CDT (04:18 UTC)
- Expired
- Aug 25, 2021, 1:15 AM CDT
- In force
- 117 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
Counties Butler County, NE, Dodge County, NE, Douglas County, NE, Polk County, NE, Sarpy County, NE, Saunders County, NE, Washington County, NE
The radar
The Omaha radar (KOAX), 54 km from the middle of the area, began a volume at 04:18 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
Omaha, NE (KOAX), launched 00:00Z, 4.3 hours before the alert went out and 54 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
- 3303 J/kg
- Mixed-layer CIN
- -92 J/kg
- Mixed-layer LCL
- 1689 m above ground
- 0-6 km bulk shear
- 24 kt
- 0-1 km storm-relative helicity
- 79 m²/s²
- 0-3 km storm-relative helicity
- 138 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 8.5
The text
As transmitted.
088 ACUS11 KWNS 250419 SWOMCD SPC MCD 250418 IAZ000-NEZ000-250615- Mesoscale Discussion 1599 NWS Storm Prediction Center Norman OK 1118 PM CDT Tue Aug 24 2021 Areas affected...Eastern NE...Southwestern IA Concerning...Severe potential...Watch unlikely Valid 250418Z - 250615Z Probability of Watch Issuance...20 percent SUMMARY...Isolated hail may be noted with thunderstorms over the next several hours. DISCUSSION...Weak low-level warm advection appears to be the primary mechanism for recent elevated thunderstorm development just north of a surface boundary across portions of eastern NE. 00z sounding from OAX exhibited substantial instability but surface-based parcels are strongly inhibited and deep-layer westerly flow is not particularly strong. Latest short-range guidance is not particularly helpful with forecast soundings not conclusive where parcel lift is occurring. Latest water-vapor imagery does suggest a pocket of moistening advancing east across this region, coincident with recent thunderstorm development. This activity will likely remain multi-cellular in nature, and unless a more extensive complex of storm mergers occurs, updrafts may struggle a bit given the veered, and seasonally weak LLJ. Hail may be the primary concern as this activity propagates toward southwestern IA. Unless it becomes more clear this activity will organize, a severe thunderstorm watch is not anticipated. ..Darrow/Bunting.. 08/25/2021 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...OAX...GID... LAT...LON 41439783 41779605 40959564 40889770 41439783
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 25, 3:02 PM CDT | Mesoscale Discussion | SPC | Boyd, Knox | 88 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.