Alert archive / Nebraska / Mesoscale Discussions in 2021
Mesoscale Discussion 1686
The Storm Prediction Center issued this mesoscale discussion at Sep 2, 2021, 7:00 PM CDT for 14 counties in Kansas; 15 counties in Nebraska. It was in force for 90 min.
The area
The outline as issued.
The facts
- Issued
- Sep 2, 2021, 7:00 PM CDT (00:00 UTC)
- Expired
- Sep 2, 2021, 8:30 PM CDT
- In force
- 90 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 487
All 29 counties
Ellis County, KS, Gove County, KS, Graham County, KS, Jewell County, KS, Lincoln County, KS, Mitchell County, KS, Ness County, KS, Osborne County, KS, Phillips County, KS, Rooks County, KS, Rush County, KS, Russell County, KS, Smith County, KS, Trego County, KS, Adams County, NE, Buffalo County, NE, Clay County, NE, Fillmore County, NE, Franklin County, NE, Hall County, NE, Hamilton County, NE, Harlan County, NE, Howard County, NE, Kearney County, NE, Merrick County, NE, Nuckolls County, NE, Phelps County, NE, Sherman County, NE, Webster County, NE
The radar
The Grand Island radar (KUEX), 92 km from the middle of the area, began a volume at 00:05 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 00:00Z, 0.0 hours before the alert went out and 208 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
- 54 J/kg
- Mixed-layer CIN
- -43 J/kg
- Mixed-layer LCL
- 1716 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- -25 m²/s²
- 0-3 km storm-relative helicity
- 16 m²/s²
- Significant tornado parameter
- -0.0
- Supercell composite
- -0.2
The text
As transmitted.
660
ACUS11 KWNS 030001
SWOMCD
SPC MCD 030000
KSZ000-NEZ000-030130-
Mesoscale Discussion 1686
NWS Storm Prediction Center Norman OK
0700 PM CDT Thu Sep 02 2021
Areas affected...portions of south central Nebraska into northern
Kansas
Concerning...Tornado Watch 487...
Valid 030000Z - 030130Z
The severe weather threat for Tornado Watch 487 continues.
SUMMARY...A couple tornadoes and damaging gusts remain possible with
the more sustained supercell updrafts over the next few hours.
DISCUSSION...KUEX and MRMS mosaic radar data depict multiple
supercells with transient low-level rotation in progress from
Kearney to Harlan Counties in NE, with more isolated attempts at
updraft intensification noted as far southwest as Gove County KS.
These storms are moving into a partially modified airmass, where
1500+ J/kg MLCAPE are common, but within a narrow corridor ahead of
the storms. However 50+ kts of effective bulk shear and 200+ m2/s2
effective SRH are present within this narrow corridor, which will
promote additional instances of low-level rotation supporting brief
tornado and damaging gust potential with the more robust,
longer-lived supercells, especially along the KS/NE border.
..Squitieri/Guyer.. 09/03/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...TOP...ICT...GID...LBF...DDC...GLD...
LAT...LON 38650076 39569994 40619963 41319928 41509836 41169771
40569751 39929767 39159810 38769847 38509910 38439966
38420029 38650076SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 2, 7:15 PM CDT | Mesoscale Discussion | SPC | Chase, Clay, Dickinson, Geary, Jackson, Lyon and 12 more | 90 min |
| Sep 2, 9:24 PM CDT | Mesoscale Discussion | SPC | Chase, Dickinson, Geary, Lyon, Marion, Morris and 3 more | 96 min |
| Sep 3, 3:18 PM CDT | Mesoscale Discussion | SPC | Barber, Clark, Comanche, Ford, Harper, Kingman and 6 more | 2 hr |
| Sep 2, 8:50 PM CDT | Mesoscale Discussion | SPC | Adams, Clay, Fillmore, Franklin, Hall, Hamilton and 12 more | 85 min |
| Sep 3, 2:20 PM CDT | Mesoscale Discussion | SPC | Banner, Kimball, Scotts Bluff, Sioux | 55 min |
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.