Alert archive / Nebraska / Mesoscale Discussions in 2019
Mesoscale Discussion 1721
The Storm Prediction Center issued this mesoscale discussion at Aug 13, 2019, 7:56 AM MDT for 9 counties in Nebraska. It was in force for 94 min.
The area
The outline as issued.
The facts
- Issued
- Aug 13, 2019, 7:56 AM MDT (13:56 UTC)
- Expired
- Aug 13, 2019, 9:30 AM MDT
- In force
- 94 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 20%
Counties Arthur County, NE, Grant County, NE, Hooker County, NE, Keith County, NE, Lincoln County, NE, Logan County, NE, McPherson County, NE, Sheridan County, NE, Thomas County, NE
The radar
The North Platte radar (KLNX), 95 km from the middle of the area, began a volume at 14:00 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 12:00Z, 1.9 hours before the alert went out and 126 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
- 67 J/kg
- Mixed-layer CIN
- -301 J/kg
- Mixed-layer LCL
- 1369 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 2 m²/s²
- 0-3 km storm-relative helicity
- 93 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.1
The text
As transmitted.
363
ACUS11 KWNS 131356
SWOMCD
SPC MCD 131356
NEZ000-131530-
Mesoscale Discussion 1721
NWS Storm Prediction Center Norman OK
0856 AM CDT Tue Aug 13 2019
Areas affected...Portions of western/central NE
Concerning...Severe potential...Watch unlikely
Valid 131356Z - 131530Z
Probability of Watch Issuance...20 percent
SUMMARY...An isolated large hail risk may continue this morning with
ongoing thunderstorms. Watch issuance is unlikely in the short term.
DISCUSSION...A pair of elevated supercells has evolved this morning
in southern Cherry County NE within a warm air advection regime
maximized around 700 mb. Short-term guidance, including the latest
run of the RAP, suggests that 25-35 kt of southwesterly flow
centered around 700 mb may persist through the rest of the morning.
These winds, along with 35-40 kt of effective bulk shear, could
maintain storm intensities as they develop southeastward along an
instability gradient present across western/central NE. Isolated
large hail will remain the primary threat for the next couple of
hours given a stable near-surface layer noted on the 12Z sounding
from LBF. Regardless, this hail threat will likely remain too
isolated to justify watch issuance in the short term (through the
rest of the morning). But, the severe threat will likely increase
later today across parts of southern/western NE as the atmosphere
destabilizes and surface-based storms develop.
..Gleason/Grams.. 08/13/2019
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LBF...CYS...
LAT...LON 42580301 42870292 42910242 42280099 41710028 41140025
40740043 40740117 41310187 41990253 42580301SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 13, 11:32 AM MDT | Mesoscale Discussion | SPC | Chase, Cheyenne, Deuel, Dundy, Garden, Keith and 2 more | 118 min |
| Aug 13, 11:49 AM MDT | Tornado Watch | SPC | Arthur, Chase, Deuel, Dundy, Frontier, Garden and 6 more | 7 hr |
| Aug 13, 2:04 PM MDT | Mesoscale Discussion | SPC | Chase, Dundy, Frontier, Hayes, Hitchcock, Keith and 3 more | 86 min |
Nearby
Mesoscale Discussions in Nebraska, 2019Every mesoscale discussion in 2019
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.