Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 171956

Area Forecast Discussion
National Weather Service Omaha/Valley NE
256 PM CDT Fri Mar 17 2017

.SHORT TERM...(Tonight through Monday)
Issued at 255 PM CDT Fri Mar 17 2017

Temperatures will be the main forecast problem into Sunday, with
potential for low clouds moving in Saturday night and lingering
into Sunday also a concern.

A ridge of cool high pressure will build over the area tonight,
then slide east on Saturday. Northwest winds have been bringing in
somewhat drier air and with not much sky cover we look for lows in
the mid 20s to lower 30s. Due to a cool start and weak to moderate
mixing on Saturday, highs should reach the mid and upper 50s in
western Iowa / mid 50s to lower 60s in eastern Nebraska.

Increasing southerly flow should bring low level moisture and
possibly low clouds into the area Saturday night, as suggested by
the 925 mb and 850 mb relative humidity progs from the GFS. The
pattern also suggests that there may be some drizzle, but did not
add drizzle to the forecast at this time. There is also some
elevated instability that moves into the area. Best chances for
any measurable precipitation Sunday afternoon or Sunday evening
should stay to our east and southeast. Will have to keep an eye on
that though because a fairly strong front is expected to push
down through the area Sunday evening.

Record highs for Sunday are - Lincoln, 82 set in 1921 / Omaha,
85 set in 1976 / Norfolk, 82 set in 1921. The fire danger could
reach the very high category in southeast Nebraska.

On Monday, it will be quite a bit cooler with highs in the 50s for
our northern zones and mostly upper 50s to lower 60s in southwest
Iowa and southeast Nebraska.

.LONG TERM...(Monday night through Friday)
Issued at 255 PM CDT Fri Mar 17 2017

This period in general will be unsettled, with several chances for
light precipitation for at least parts of the area from Monday
night into Wednesday.

There is fairly good model agreement with the large scale pattern
at the start of this period. A 500 mb ridge should be over the
Rockies, with a trough off the west coast. The trough will deepen
and the ridge will move east, and then by Thursday a portion of
the trough should be moving into the four corners region. There
are some model differences with the details, but a fairly strong
disturbance is expected to move through the central Plains for
Thursday into Friday. Started to increase POPs Wednesday night
(into the 30-50 percent range) and 40-70 percent for Thursday. The
12Z operational GFS was a bit stronger with the mid level wave,
so preferred a solution closer to a blend of the 12Z GFS ensemble
mean and the 12Z ECMWF. The Canadian model was slower and was also
considered to be an outlier, so not given much weight. The 12Z
ECMWF was the strongest with the surface low, and appeared too
strong at this time (especially for late Thursday night into
Friday morning).

Nighttime temperatures suggest that a rain/snow mix is possible,
but for now chances for accumulating snow look to be low.


.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1220 PM CDT Fri Mar 17 2017

VFR conditions are expected through the TAF cycle, with scattered
clouds at around cirrus level and unrestricted visibility.
Northwest winds at around 10-15kt will subside this evening,
becoming light and variable into Saturday morning as high pressure
moves across the area.




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