Severe Storm Outlook Narrative (AC)
Issued by NWS

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44

ACUS11 KWNS 160904
SPC MCD 160904

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

..Mosier.. 03/16/2018

...Please see for graphic product...


LAT...LON   42440080 42310143 42060249 41820385 42140434 42930433
            43710375 44000272 44160134 43909825 43009746 42619844
            42440080 is the U.S. government's official web portal to all federal, state and local government web resources and services.