Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 200540

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1140 PM CST Thu Jan 19 2017

.SHORT TERM...(tonight through Sunday)
Issued at 239 PM CST Thu Jan 19 2017

Biggest issue tonight and Friday will be lingering low clouds,
widespread fog, and possible drizzle. Visibility ranges from 1-7
miles at mid afternoon across the region, but is expected to drop
again as daylight fades. Our consensus blends suggest widespread
1/2 mile will be possible overnight, with areas at 1/4 mile. Thus,
will issue a dense fog advisory from 8 pm to 9 am, which should
cover the worst of it. Can`t say that a site or two might not go
down before 8 pm, and can`t say that a site or two won`t linger
past 9 am. HRRR/RAP even suggest that some visibility improvement
could occur in northeast NE later in the night, and if that
happens, the fog advisory could be lifted if that indeed develops.
Regarding any precipitation, general feeling is that it will be a
drizzly night and through the day Friday, but not really a
measurable rain event, although wouldn`t be surprised for some
locations to pick up a hundredth or two of an inch given the
prolonged nature.

The next trough, now across the west coast quickly moves across
the Rockies and onto the Plains later on Friday. Pacific moisture
associated with this feature should help increase measurable
precipitation chances by late Friday afternoon and Friday night,
and will go with 40-60% pops, but QPF generally remains below
1/10". Temps remain above freezing. As some colder air tries to
work into the system, this could result in an hour or two of a
wintry mix in a couple of counties in northeast NE.

A wintry mix of precip chances may linger in northeast NE Saturday
morning, and still a slight chance of rain in east central NE and
northwest IA, but should be moving out of the area during the

Quiet weather for the remainder of Saturday into Sunday as a
closed low moves well south of the region across the southern

.LONG TERM...(Sunday night through Thursday)
Issued at 239 PM CST Thu Jan 19 2017

Big weather make for the extended will be the result of the next
strong trough moving onto the west coast, then across the Rockies
on Monday. This induces lee cyclogenesis Monday night, with a
surface low moving to the KS/NE border region by daybreak Tuesday,
then to the mid Mississippi Valley region by daybreak Wednesday.
Models are in much better agreement today than yesterday, so
confidence is now increasing on a potential winter storm that will
affect the region. Precipitation initially develops Monday night
within the warm air advection pattern and may initially begin as
rain or snow, but eventually turns to all snow by Tuesday night
and lingers through early Wednesday. Both GFS and ECMWF have
highest snowfall amount axis just north of I80, but with lower
amounts all the way down to the KS/NE border. While snowfall
amounts will eventually be a hot topic, right now, it`s still 2
days to soon to discuss amounts. We are continuing to watch this
system closely as it could have a significant winter impact on
the area as models converge on a solution.

Remainder of the extended forecast should be dry, although another
minor wave could be coming in from the northern plains just
beyond the period by next Thursday night into Friday.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1137 PM CST Thu Jan 19 2017

Variable cigs/vsbys between LIFR and MVFR will persist for a few
more hours, but low level moisture continuing to advect into
eastern Nebraska suggests both cigs and vsbys will drop to LIFR or
VLIFR categories by 09Z and linger through 18Z. Some improvement
is likely then, but still IFR conditions will rule. Areas of
drizzle are forecast to develop by late afternoon and continue
through Friday evening, reinforcing the low cigs and vsbys.


NE...Dense Fog Advisory until 9 AM CST Friday for NEZ011-012-015>018-

IA...Dense Fog Advisory until 9 AM CST Friday for IAZ043-055-056-069-



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