Alert archive / Nebraska / Mesoscale Discussions in 2021
Mesoscale Discussion 982
The Storm Prediction Center issued this mesoscale discussion at Jun 15, 2021, 7:34 PM CDT for Jewell County, Phillips County, Smith County, Kansas; 6 counties in Nebraska. It was in force for 116 min.
The area
The outline as issued.
The facts
- Issued
- Jun 15, 2021, 7:34 PM CDT (00:34 UTC)
- Expired
- Jun 15, 2021, 9:30 PM CDT
- In force
- 116 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 5%
Counties Jewell County, KS, Phillips County, KS, Smith County, KS, Adams County, NE, Buffalo County, NE, Franklin County, NE, Hall County, NE, Kearney County, NE, Webster County, NE
The radar
The Grand Island radar (KUEX), 28 km from the middle of the area, began a volume at 00:35 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 nearest sounding before it
N. Platte/Lee Bi, NE (KLBF), launched 00:00Z, 0.6 hours before the alert went out and 187 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
- 1142 J/kg
- Mixed-layer CIN
- -123 J/kg
- Mixed-layer LCL
- 2817 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 15 m²/s²
- 0-3 km storm-relative helicity
- 73 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.8
The text
As transmitted.
151
ACUS11 KWNS 160035
SWOMCD
SPC MCD 160034
NEZ000-KSZ000-160230-
Mesoscale Discussion 0982
NWS Storm Prediction Center Norman OK
0734 PM CDT Tue Jun 15 2021
Areas affected...Southern Nebraska and far northern Kansas
Concerning...Severe potential...Watch unlikely
Valid 160034Z - 160230Z
Probability of Watch Issuance...5 percent
SUMMARY...A single supercell may pose a very isolated severe
wind/hail risk to south-central Nebraska over the next 1-2 hours.
The coverage of the threat should be minimal, and the duration may
not extend beyond a couple of hours. A watch is not expected.
DISCUSSION...A single thunderstorm has developed across
south-central NE over the past hour. While this region has moderate
mixed-layer instability and nearly 40 knots of effective bulk shear,
a strong cap largely remains in place. A pocket of higher theta-e
air across south-central NE lies within a weak confluence axis,
which has led to a local weakening of the cap that has allowed the
thunderstorm to develop. Recent GOES trends show some degree of
cloud-top cooling with splitting supercell structures noted in KUEX
imagery. This suggests that the supercell is robust enough to
persist for at least one to two hours despite the weak forcing for
ascent. Additional convection along the confluence axis in the high
theta-e pocket is possible (as indicated by a couple of weak
convective towers), but is not likely. Severe hail/wind are possible
with this storm, but the duration is uncertain after 02 UTC given
the onset of diurnal cooling.
..Moore/Guyer.. 06/16/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GID...
LAT...LON 40809920 40989895 40959857 40779835 40509821 40189813
39889811 39579807 39479835 39489872 39519908 39699941
40169940 40529932 40809920Nearby
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.