MD 0122 CONCERNING WINTER MIXED PRECIPITATION FOR SOUTHERN SD…NORTHERN NE…FAR SOUTHEAST/EAST-CENTRAL WY
Mesoscale Discussion 0122
NWS Storm Prediction Center Norman OK
0404 AM CDT Fri Mar 16 2018
Areas affected...Southern SD...Northern NE...Far
Southeast/East-Central WY
Concerning...Winter mixed precipitation
Valid 160904Z - 161300Z
SUMMARY...A transition to winter precipitation is anticipated soon
with this mixed winter precipitation expected to persist for the
next several hours.
DISCUSSION...Current regional radar imagery shows a band of
precipitation, with embedded heavier cores and occasional lightning,
arcing from southwest SD through southeast NE. This band is on the
eastern periphery of the low-level jet where isentropic ascent is
maximized. This ascent, as well as ongoing moisture advection, is
shown well on the 300K theta surface. Mature cyclone responsible for
the low-level jet and increased forcing for ascent will continue to
fill over the next few hours, leading to a gradual weakening of the
low-level jet and isentropic ascent. However, precipitation will
likely continue for at the next few hours with some expansion in
light/moderate precipitation possible as the system moves eastward.
Wet-bulb effects are expected to cool surface temperatures across
the region a few degrees, resulting in a transition to mixed winter
precipitation. Warm nose in place across north-central NE and
south-central/southeast SD is expected to result in dominant
precipitation type of freezing rain. Rain rates in this area could
top 0.05"/hr in the heavier cores. Farther west, less pronounced
warm nose will result in profiles remaining cold enough for
primarily snow. Generally moderate snowfall rates are anticipated
but occasional/brief instances of snowfall rates around 1"/hr are
possible.
..Mosier.. 03/16/2018
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FSD...OAX...ABR...LBF...UNR...CYS...
LAT...LON 42440080 42310143 42060249 41820385 42140434 42930433
43710375 44000272 44160134 43909825 43009746 42619844
42440080
from SPC Mesoscale Discussions http://bit.ly/2IscZWE
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