Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 221732
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1132 AM CST Mon Jan 22 2018

.UPDATE...
Issued at 1120 AM CST Mon Jan 22 2018

Major winter storm continues with northwest winds beginning to
gust higher across areas near the Missouri river. Gusts have been
peaking at 30-40mph with some 50mph and greater gusts out there.
Tricky situation for the biggest metro area in the state...as
Douglas/Sarpy counties are the dividing line between significant
amounts of snow in the west to only slush in the east. With the
winds becoming northwest, feel we should be able to cool the temps
at Eppley and Offutt so that they turn over to a more
accumulating light snow vs just slush. Have updated snowfall
amounts for the metro area, giving the eastern portions less
snowfall. Otherwise, no major changes to headlines. Also
diminished Lincoln snowfall totals a bit.

&&

.SHORT TERM...(Today through Wednesday)
Issued at 411 AM CST Mon Jan 22 2018

Major Winter Storm moving into parts of eastern Nebraska today. Will
continue with current headlines.

Moderate to heavy snows with wind gusts to 50 mph were occurring
this morning in central and western Nebraska, causing blizzard
conditions there. This activity was occurring in northwest quadrant
of low pressure system that was centered in north central Kansas as
of 3 AM. As low tracks east and northeast today, parts of eastern
Nebraska and west central Iowa will be affected by these same
blizzard conditions.

Snow has already fallen in parts of northeast Nebraska where
temperatures have dropped below 33F and spiral bands of seeder
clouds have rotated around low pressure system. As low tracks east
this morning, trowal region of system will be firmly entrenched over
northeast Nebraska. Meanwhile mid level dry slot rotating north
around mid level low will spread across far eastern Nebraska and
southwest Iowa. The boundary where trowal and dry slot meet will be
a favored area for convective snows where rates of 1 to 2 inches an
hour could be realized. In fact, we have already seen a few
lightning strikes near and southwest of Columbus. Latest short-range
guidance and extrapolation of satellite loops suggest this is likely
to occur along a line from Albion to Norfolk, Wayne and Macy
Nebraska this morning.

A gradual change from rain to a mix then snow will occur northwest
to southeast this morning and early afternoon as colder air on back
side of low spreads south. By noon today, areas from near Missouri
Valley to Omaha and into southeast Nebraska will be the battle
ground between warmer air wrapping around low from the southeast and
colder air plunging south on the back side. Thus the transition to
snow there will likely hold off until early afternoon, while areas
just to the west, like from Tekamah to Fremont, Lincoln and
Beatrice, will likely switch over by mid morning.

The timing of the change to all snow will play a huge role in the
amount of snow, ranging up to 6 inches where a mid-morning
transition occurs, to closer to 1 or 2 inches where an early
afternoon switch happens.

In any case, accompanying the switch to snow will be a dramatic
increase in wind speeds leading to greatly reduced visibilities in
blowing and falling snow. Thus even with lighter amounts, hazardous
driving conditions are likely. One positive note is temperatures
have been mild as of late so ground temperatures will promote some
melting initially. And air temperatures in the upper 20s to lower
30s where snow is falling suggests a heavy, wet snow may not blow
around quite as easily. But the heavy, wet character of the snow
combined with wind gusts over 40 mph may have an impact on trees and
power lines.

System will be working east of our area this afternoon and evening,
bringing a change to snow over all of southwest Iowa by mid to
late afternoon. Snow will end from west to east, beginning late
afternoon in the Norfolk and Columbus areas, then along the
Missouri River by midnight, and shortly after midnight in
southwest Iowa. Winds will gradually subside as well during the
evening, but are expected to gust over 40 much of the afternoon.

After this system rolls east tonight, a fairly benign weather
pattern follows into mid week. Mid level flow flattens by Wednesday
with temperatures rebounding toward 40 by then.

.LONG TERM...(Wednesday night through Sunday)
Issued at 411 AM CST Mon Jan 22 2018

The longer term period appears to be uneventful save for some
cooling by the weekend. Mid level ridging is forecast over the
Plains by Thursday, ahead of a trough expected to swing through the
region Friday night and Saturday. Mild temperatures in the 40s or
lower 50s are a potential, but may be tempered somewhat by lingering
snow cover. Cooler air spills south behind the trough for Saturday
when temperatures dip back into the 30s, with a reinforcing shot of
cold air making it a bit more chilly on Sunday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1120 AM CST Mon Jan 22 2018

IFR to LIFR conditions continue at KOFK with KLNK and KOMA varying
between IFR and MVFR. Think KOMA will begin to see more of a
turnover to snow as winds have come around to the northwest,
bringing cooler temps. Have reduced snowfall amounts at both KOMA
and KLNK with stronger forcing keeping the higher amounts out of
the airports. Visibilities will remain lower through the afternoon
and evening hours before improving as the winds subside overnight.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Winter Storm Warning until 6 PM CST this evening for NEZ052-053.

     Winter Weather Advisory until 6 PM CST this evening for NEZ067-
     068-088>092.

     Blizzard Warning until 6 PM CST this evening for NEZ011-012-
     015>018-030>034-042>045-050-051-065-066-078.

IA...Winter Storm Warning until 6 PM CST this evening for IAZ055.

     Winter Weather Advisory until 6 PM CST this evening for IAZ056-
     069-079-090.

     Blizzard Warning until 6 PM CST this evening for IAZ043.

&&

$$

UPDATE...Kern
SHORT TERM...Dergan
LONG TERM...Dergan
AVIATION...Kern



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