Alert archive / Nebraska / Mesoscale Discussions in 2021
Mesoscale Discussion 1695
The Storm Prediction Center issued this mesoscale discussion at Sep 5, 2021, 3:54 AM MDT for 18 counties in Nebraska. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Sep 5, 2021, 3:54 AM MDT (09:54 UTC)
- Expired
- Sep 5, 2021, 6:30 AM MDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 5%
Counties Arthur County, NE, Chase County, NE, Custer County, NE, Dawson County, NE, Dundy County, NE, Frontier County, NE, Furnas County, NE, Gosper County, NE, Hayes County, NE, Hitchcock County, NE, Hooker County, NE, Keith County, NE, Lincoln County, NE, Logan County, NE, McPherson County, NE, Perkins County, NE, Phelps County, NE, Red Willow County, NE
The radar
The North Platte radar (KLNX), 118 km from the middle of the area, began a volume at 09:57 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, 9.9 hours before the alert went out and 33 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
- 724 J/kg
- Mixed-layer CIN
- -12 J/kg
- Mixed-layer LCL
- 1466 m above ground
- 0-6 km bulk shear
- 31 kt
- 0-1 km storm-relative helicity
- 34 m²/s²
- 0-3 km storm-relative helicity
- 143 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 0.9
The text
As transmitted.
178
ACUS11 KWNS 050955
SWOMCD
SPC MCD 050954
NEZ000-COZ000-051230-
Mesoscale Discussion 1695
NWS Storm Prediction Center Norman OK
0454 AM CDT Sun Sep 05 2021
Areas affected...Southwest and Central Nebraska
Concerning...Severe potential...Watch unlikely
Valid 050954Z - 051230Z
Probability of Watch Issuance...5 percent
SUMMARY...An isolated large hail will likely continue across parts
of southwest and central Nebraska over the next few hours. The hail
threat should remain marginal and a weather watch will probably not
be needed.
DISCUSSION...The latest radar imagery from North Platte shows three
small clusters of thunderstorms over southwest and central Nebraska.
The western most cluster is located in the center of a pocket of
moderate instability. The RAP is estimating MUCAPE within this
pocket in the 1500 to 2000 J/kg range. However, a sharp temperature
inversion evident on forecast soundings is keeping this convection
elevated. Convective development will continue to occur over the
next few hours in western and central Nebraska as a shortwave trough
over the central Rockies moves southeastward into the central High
Plains. Large-scale ascent ahead of the trough along with steep
mid-level lapse rates and moderate deep-layer shear will be
favorable for hail with elevated supercells. The threat should
gradually move southeastward into the south-central Nebraska by
around daybreak, where a marginal hail threat will exist.
..Broyles/Edwards.. 09/05/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GID...LBF...GLD...BOU...
LAT...LON 41870161 41330207 40860223 40640219 40230194 40010115
40099991 40149969 40429930 41099923 41469976 41960074
41870161Nearby
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.