Alert archive / Nebraska / Mesoscale Discussions in 2017
Mesoscale Discussion 1503
The Storm Prediction Center issued this mesoscale discussion at Aug 15, 2017, 6:05 PM MDT for Logan County, Sedgwick County, Colorado; 16 counties in Nebraska. It was in force for 115 min.
The area
The outline as issued.
The facts
- Issued
- Aug 15, 2017, 6:05 PM MDT (00:05 UTC)
- Expired
- Aug 15, 2017, 8:00 PM MDT
- In force
- 115 min
- Issued by
- the Storm Prediction Center
Counties Logan County, CO, Sedgwick County, CO, Arthur County, NE, Blaine County, NE, Brown County, NE, Cherry County, NE, Custer County, NE, Deuel County, NE, Garden County, NE, Grant County, NE, Hooker County, NE, Keith County, NE, Lincoln County, NE, Logan County, NE, Loup County, NE, McPherson County, NE, Perkins County, NE, Thomas County, NE
The radar
The North Platte radar (KLNX), 81 km from the middle of the area, began a volume at 00:04 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, 0.1 hours before the alert went out and 93 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
- 843 J/kg
- Mixed-layer CIN
- -15 J/kg
- Mixed-layer LCL
- 2134 m above ground
- 0-6 km bulk shear
- 14 kt
- 0-1 km storm-relative helicity
- 54 m²/s²
- 0-3 km storm-relative helicity
- 92 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
482
ACUS11 KWNS 160006
SWOMCD
SPC MCD 160005
NEZ000-COZ000-160200-
Mesoscale Discussion 1503
NWS Storm Prediction Center Norman OK
0705 PM CDT Tue Aug 15 2017
Areas affected...Parts of western and central Nebraska
Concerning...Severe Thunderstorm Watch 452...
Valid 160005Z - 160200Z
The severe weather threat for Severe Thunderstorm Watch 452
continues.
SUMMARY...An evolving cluster of thunderstorms is possible across
the region by 8-10 PM CDT, accompanied by increasing potential for
damaging wind gusts.
DISCUSSION...Increasing thunderstorm development is underway along a
rough west-east zone of enhanced low-level warm advection extending
across central Nebraska, with an additional further increase in
thunderstorm development probable along a cold front now across the
Nebraska Panhandle. Enhanced by convective outflow, models suggest
that the cold front may begin surging eastward during the next few
hours, as the zone of warm advection remains quasi-stationary or
slowly lifts northward.
Considerable consolidation and upscale convective growth along these
boundaries, particularly near their intersection, in the presence of
large boundary layer CAPE (2000-3000 J/kg), may become increasingly
centered northwest of Broken Bow by 01-03Z. This may become
sufficient to support the evolution of a mesoscale convective vortex
and associated rear inflow jet that could be accompanied by an
increase in potential for damaging surface gusts. Otherwise, deep
layer flow and shear are rather weak, though nocturnally
strengthening low-level jet (30-40 kt) may augment development later
this evening.
..Kerr.. 08/16/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GID...LBF...BOU...CYS...
LAT...LON 41610266 41960218 42700141 42580012 41419903 40750042
40660324 41610266SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 15, 9:58 PM MDT | Mesoscale Discussion | SPC | Custer, Dawson | 92 min |
Nearby
Mesoscale Discussions in Nebraska, 2017Mesoscale Discussions in Colorado, 2017Every mesoscale discussion in 2017
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.