Mesoscale Discussion 39

Issued

Jan 22, 2018, 9:20 AM CST (15:20 UTC)

Expired

Jan 22, 2018, 3:15 PM CST

In force

6 hr

Issued by

the Storm Prediction Center

The Minneapolis radar (KMPX), 159 km from the middle of the area, began a volume at 15:23 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.

467 
ACUS11 KWNS 221521
SWOMCD
SPC MCD 221520 
WIZ000-MNZ000-IAZ000-NEZ000-SDZ000-222115-

Mesoscale Discussion 0039
NWS Storm Prediction Center Norman OK
0920 AM CST Mon Jan 22 2018

Areas affected...Portions of eastern NE...far southeastern
SD...northern/western IA...southern MN...and western WI

Concerning...Heavy snow 

Valid 221520Z - 222115Z

SUMMARY...Heavy snow, with rates around 1-2 inches per hour, will
spread northeastward through this afternoon. Blizzard conditions
will continue across parts of eastern NE into far southeastern SD,
western/northern IA, and southern MN for at least a few more hours.

DISCUSSION...A mature mid/upper-level cyclone centered over eastern
NE/KS this morning will move east-northeastward across IA/MO and
towards IL by later today. A zone of strong low/mid-level
frontogenetic forcing on the northern extent of this cyclone is
supporting a band of moderate to heavy snow extending from eastern
NE into western/northern IA and southern MN. This heavy snow band
will develop northeastward into more of southern MN and eventually
parts of western WI by this afternoon. Snowfall rates of 1-2 inches
per hour will be common within this band, with locally higher rates
possible within where localized convective enhancement occurs.
Sporadic lightning strikes may continue given the very strong
large-scale forcing and steepened mid-level lapse rates.

Additionally, a strong surface pressure gradient exists on the
northern side of a low centered over IA as of 15Z, which is
supporting blizzard conditions across parts of eastern NE, far
southeastern SD, western/northern IA, and southern MN. Here,
frequent northerly/northeasterly gusts of 35-50 mph are resulting in
blowing snow with substantially reduced visibilities (1/4 of a mile
or less). These blizzard conditions are expected persist for at
least the next few hours.

..Gleason.. 01/22/2018

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...ARX...MPX...DMX...FSD...OAX...GID...

LAT...LON   44029142 43629235 43279342 42579519 41119622 40939779
            41659826 42779779 44239582 45189339 45459190 45279101
            44379085 44029142

Mesoscale Discussions in Minnesota, 2018Mesoscale Discussions in Nebraska, 2018Mesoscale Discussions in Iowa, 2018Every mesoscale discussion in 2018

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.