Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

Home | Current Version | Previous Version | Graphics & Text | 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

FXUS63 KOAX 182030

Area Forecast Discussion
National Weather Service Omaha/Valley NE
230 PM CST Wed Jan 18 2017

.SHORT TERM...(tonight through Saturday)
Issued at 200 PM CST Wed Jan 18 2017

A couple of weather systems will bring drizzle or rain to the area
in the short term.

The first system was spinning across the front range of the
Rockies near the CO/KS border and will lift northward across the
area through early Friday. Low level moisture across the southern
Plains will quickly stream northward tonight with dewpoints
remaining the the lower to mid 30s overnight. This should result
in an area of low stratus developing in northeast NE, and maybe a
slightly higher MVFR deck along/south of I80. Given the cool
ground and high dewpoints, fog will also likely develop, and the
question is how dense will the fog be. SREF and various short
range models suggest it could be locally dense north of I80, but
will hold off any advisory for now and see how it develops. It`s
also within this axis that the Nam was hinting at some patchy
drizzle as well. Temps may hold right around freezing, but not
sure the low level moisture is deep enough, and whether there
would be enough lift to generate any precipitation. It`s
something else that we`d have to monitor for potential development
and add to the forecast later on if necessary.

Cloudy skies continue Thursday into Thursday night, with low level
moisture depth increasing sufficiently to support drizzle just
about everywhere. Fortunately, temperatures will be in the 40s
Thursday, and remain in the lower to mid 30s Thursday night.
Added fog back to the weather grids for Thursday night with most
guidance suggesting fog and potentially pretty low visibility and
very low, essentially surface based clouds.

The first wave moves out Friday, but the clouds and patchy drizzle
remain, and may even begin to increase to Friday evening as the
next stronger wave approaches. By this time, we do have a little
deeper moisture to work with, which may finally result in
measurable precipitation, mainly along and north of I80, but
again, due to warm temperatures aloft, in the for of rain. This
second system does have a surface circulation associated with it,
and some colder air tries to wrap around on the northwest side,
but it may not be soon enough. Weather grids do have a wintry mix
in northeast NE late Friday night for an hour or two, but the
dynamics and lift associated with the low are likely just ahead
of the colder air, except for just a couple of counties.

Most of Saturday will dry, save for the handful of counties on our
far northern border where lingering precip chances exist Saturday
morning. Highs Saturday still in the 40s.

.LONG TERM...(Saturday night through Wednesday)
Issued at 200 PM CST Wed Jan 18 2017

Late in the weekend, a fairly strong closed low moves well south
of the region through the southern Plains into the lower
Mississippi River valley. Focus shifts to the next trough moving
onto the west coast, which eventually moves across the Rockies and
brings us a chance of rain and snow by Tuesday into Wednesday. GFS
has remained fairly consistent in showing a pretty substantial
winter storm setting up for somewhere on the Plains, with rain
chances ahead of it and snow and windy conditions behind it. Most
recent ECMWF now substantially disagrees with the GFS solution,
which is the first departure from consistency for that model in
the last couple of days. And it`s just outside the window of the
Canadian model. Thus, the details of how the weather will unfold
next week are somewhat uncertain. We`ll still have 40-60% of
precipitation Tuesday through Wednesday, with rain and snow, but
given model disparity, overall confidence is a little low right
now in the details. As always, stay tuned. We`ll continue to
watch closely.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1135 AM CST Wed Jan 18 2017

Deteriorating conditions are on tap later tonight given
combination of wet ground along with gradual influx of llvl
moisture into ern Neb. At this point expect conditions to fall
into MVFR territory during the early evening hours before dropping
to IFR twd 10z-12z Thurs morning. Expect some improvement to MVFR
then around mid morning.




AVIATION...DEE is the U.S. government's official web portal to all federal, state and local government web resources and services.