SPC MD 129


MD 0129 Image

Mesoscale Discussion 0129
NWS Storm Prediction Center Norman OK
0526 PM CST Sat Feb 23 2019

Areas affected...Far eastern NE...western/central IA...southern MN

Concerning...Heavy snow 

Valid 232326Z - 240430Z

SUMMARY...Heavy snow rates of 1-2"/hour (locally greater) are
expected into this evening, with localized blizzard conditions
possible later this evening as winds increase from west to east.

DISCUSSION...Latest surface analysis depicts a deepening cyclone
centered near Kansas City at 23Z. WV imagery shows a well-developed
dry slot moving into southern IA, with thunderstorms noted on its
leading edge. Very strong deep-layer ascent to the northwest of the
low track is resulting in heavy snowfall rates in excess of 1"/hour
across eastern NE, with occasional blizzard conditions. The
rain/snow line has advanced through the Omaha area within the last
1-2 hours, with portions of northwest IA beginning to transition to

As the cyclone moves northeastward this evening and thermal profiles
cool due to strong ascent and increasing cold advection, heavy snow
will spread into a larger portion of central/northern IA and
southern MN. Snowfall rates of 1-2"/hour (locally higher) will
continue through the evening, with some thundersnow possible as
convective elements that develop on the apex of the dry slot feed
into the primary snow band. 

Blizzard conditions may also develop from west to east across this
region later this evening as low-level northwesterly flow increases
in response to the deepening surface low. While the increase in
winds may tend to coincide with decreasing snowfall rates on the
backside of the precipitation shield, increasing cold advection will
result in less water content with the remaining snowfall, resulting
in a greater tendency for reduced visibility due to blowing snow.

..Dean.. 02/23/2019

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


LAT...LON   41669637 43019591 43879552 44499424 44619302 44329224
            43819214 43319242 42629283 41949356 41489425 41259476
            41169521 41089563 41169618 41669637 

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