Alert archive / Nebraska / Mesoscale Discussions in 2021
Mesoscale Discussion 1399
The Storm Prediction Center issued this mesoscale discussion at Jul 30, 2021, 9:36 PM CDT for 4 counties in Nebraska. It was in force for 24 min.
The area
The outline as issued.
The facts
- Issued
- Jul 30, 2021, 9:36 PM CDT (02:36 UTC)
- Expired
- Jul 30, 2021, 10:00 PM CDT
- In force
- 24 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch needed soon 404
- Chance of a watch
- 95%
Counties Brown County, NE, Garfield County, NE, Loup County, NE, Rock County, NE
The radar
The North Platte radar (KLNX), 65 km from the middle of the area, began a volume at 02:35 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, 2.6 hours before the alert went out and 137 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
- 2904 J/kg
- Mixed-layer CIN
- -55 J/kg
- Mixed-layer LCL
- 1646 m above ground
- 0-6 km bulk shear
- 27 kt
- 0-1 km storm-relative helicity
- 115 m²/s²
- 0-3 km storm-relative helicity
- 200 m²/s²
- Significant tornado parameter
- 0.6
- Supercell composite
- 17.8
The text
As transmitted.
564 ACUS11 KWNS 310236 SWOMCD SPC MCD 310236 NEZ000-310300- Mesoscale Discussion 1399 NWS Storm Prediction Center Norman OK 0936 PM CDT Fri Jul 30 2021 Areas affected...Northern Nebraska Concerning...Severe potential...Watch needed soon 404... Valid 310236Z - 310300Z Probability of Watch Issuance...95 percent SUMMARY...Severe thunderstorm watch will be issued soon for portions of northern Nebraska. DISCUSSION...East-west band of convection has gradually solidified from eastern Cherry County to Holt County. It appears this activity has organized sufficiently for continued slow southward propagation over the next several hours. Hail and gusty winds are the main threats. ..Darrow.. 07/31/2021 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LBF... LAT...LON 42580068 42419872 41799858 41909987 42160079 42580068
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 30, 8:16 PM CDT | Mesoscale Discussion | SPC | Cass, Douglas, Gage, Johnson, Lancaster, Nemaha and 5 more | 59 min |
| Jul 30, 8:47 PM CDT | Severe Thunderstorm Watch | SPC | Cass, Gage, Johnson, Lancaster, Nemaha, Otoe and 2 more | 5 hr |
| Jul 30, 9:46 PM CDT | Severe Thunderstorm Watch | SPC | Antelope, Blaine, Boone, Brown, Garfield, Greeley and 8 more | 4 hr |
| Jul 30, 11:05 PM CDT | Mesoscale Discussion | SPC | Nemaha, Richardson | 85 min |
| Jul 30, 11:09 PM CDT | Mesoscale Discussion | SPC | Nemaha, Richardson | 96 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.