ACUS11 KWNS 141059
SWOMCD
SPC MCD 141058
ILZ000-WIZ000-IAZ000-MOZ000-141700-

Mesoscale Discussion 2267
NWS Storm Prediction Center Norman OK
0458 AM CST Sat Dec 14 2024

Areas affected...eastern Iowa...northwestern Illinois...and vicinity

Concerning...Freezing rain

Valid 141058Z - 141700Z

SUMMARY...Freezing rain -- at rates locally in excess of 0.10"/hour
-- will continue spreading north-northeastward across eastern Iowa
and into northwestern Illinois through midday.

DISCUSSION...Latest radar loop shows an expansive area of
precipitation ongoing from the Arklatex region northward across the
Lower Missouri and Mid Mississippi Valleys this morning. The
precipitation is occurring in an area of warm
advection/quasigeostropic ascent, east of a 1013 mb surface low over
central Kansas, and associated upper low moving eastward across
Nebraska and Kansas this morning.

A cold boundary layer remains in place across this region, on the
western fringe of a 1048 mb high centered in the vicinity of the Pennsylvania/New York border area. As low-level theta-e advection
continues ascending atop the cold low-level airmass, resulting
ascent will continue to support the broad/ongoing area of
precipitation over the next several hours.

Currently, the surface freezing line extends from the Omaha area east-southeastward into southern Illinois north of the St. Louis
area. North of this line, mixed/wintry precipitation is observed,
mainly in the form of freezing rain. The most substantial freezing
rain has occurred over southeastern Iowa recently, with KOTM
(Ottumwa) reporting 0.13" in the past hour. This area of moderate precipitation will continue spreading north-northeastward with time,
across eastern Iowa and northwestern Illinois, with ice
accumulations likely.

..Goss.. 12/14/2024

ATTN...WFO...LOT...ILX...MKX...LSX...DVN...ARX...DMX...EAX...

LAT...LON 40859281 42109289 43389206 43369069 42498949 41588893
40229008 40169187 40859281


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