Severe Storm Outlook Narrative (AC)
Issued by NWS
ACUS11 KWNS 240005
SPC MCD 240005
Mesoscale Discussion 0200
NWS Storm Prediction Center Norman OK
0605 PM CST Thu Feb 23 2017
Areas affected...Portions of Nebraska...far southeastern South
Dakota...northwestern Iowa...and far southern Minnesota
Valid 240005Z - 240600Z
SUMMARY...Heavy snow will continue to develop and spread northeast
across the region this evening into the overnight hours. Snowfall
rates of 1+ inches per hour will be possible. Additionally,
occasional blizzard conditions will become more likely with eastward
extent, as northeasterly winds increase through the evening.
DISCUSSION...A fairly expansive region of precipitation continues to
evolve across the region early this evening, with snowfall generally
across central and northern Nebraska, extending to the northeast
into southern Minnesota. With the slow approach of the western US
trough (and several impulses embedded within this cyclonic flow),
ongoing deformation banding near Cherry County, NE, should continue
to evolve east/northeast this evening, with snowfall rates up to an
inch per hour or so impacting northern Nebraska and far southern
To the southeast, radar data display blossoming convection across
northern Kansas and far southern Nebraska, likely in response to
increasing mid-level warm-air advection / adiabatic ascent. This
trend will continue through the evening and shift eastward towards
the Missouri River, with strengthening frontogenetic circulations
assisting precipitation intensity. KUEX and KOAX correlation
coefficient data indicate the transition zone from snow to sleet
exists from Webster County, NE, northeastward to Burt County, NE.
This line should gradually move eastward this evening, with the
heaviest snow focused just to the northwest of the transition zone
(from central Nebraska to northwestern Iowa and southern Minnesota).
Here, snowfall rates of 1-2 inches per hour will be possible.
Additionally, as the low-level cyclone deepens over Kansas/Missouri
this evening, surface wind gusts upwards of 40 mph may result in
occasional blizzard conditions, especially over northwestern Iowa
and southern Minnesota.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 42640116 43119976 43599672 43709548 43789340 43749291
43489268 43039299 42799316 42079411 41679532 41389625
40949714 40659760 40409859 40489946 40860054 41290101