Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 161930

Area Forecast Discussion
National Weather Service Omaha/Valley NE
230 PM CDT Wed Aug 16 2017

.SHORT TERM...(Tonight through Saturday)
Issued at 138 PM CDT Wed Aug 16 2017

24 hour rainfall amounts in parts of the Platte River basin
averaged 4 to 6 inches last night, with some unverified of 6 to 8
inch reports. This has resulted in widespread areal flooding for
Butler, and portions of Colfax and Saunders counties. This will
lead to river flooding through the next couple of days along the
Big Blue river in southeast NE.

Meanwhile, the area of low pressure and associated front that
brought the excessive heavy rainfall was pushing east of the area
through mid afternoon. Precip had essentially cleared the
forecast area for now, with high resolution CAMs suggesting that
additional strong to severe development will be well south and
east of our area of concern. Although, there may still be isolated
showers that could linger this evening.

Thursday should be dry with northwesterly winds, breezy in the
morning but diminishing by early evening. Nearly all model suites
suggest that another wave and associated frontal boundary could
be moving into area from the west northwest Thursday night into
Friday, bringing the next chance of showers/storms. May be lingering
or isolated storms south of I80 Friday afternoon/evening, which
sets the stage for dry and warm weather again on Saturday.

.LONG TERM...(Saturday night through Wednesday)
Issued at 138 PM CDT Wed Aug 16 2017

Both the GFS and Canadian suggest that with a relatively zonal
flow aloft, a weak wave moves out of the central Rockies and
could bring a small chance of showers and storms into the forecast
area Sunday. More importantly, the GFS and Canadian suggest that
another similar upper level impulse could be moving out of the
Rockies Sunday night into early Monday, which these models have
been consistently showing for the last couple of days. Meanwhile,
the EC remains dry Sunday night into Monday for our area, with its
energy focused a little further north into the northern Plains.
Thus, the local forecast will continue to carry 30-50% chance of
storms during this time with more reliance on GFS/Canadian blends.
Model variability 5 days out can still change quite a bit so
there remains some uncertainty of the specifics of of how much
cloud cover would remain for a 4 hour window late Monday morning
into early Monday afternoon for the eclipse.

The models do have somewhat better agreement that a frontal
boundary gets pushed into the area Monday night then south of the
area into Tuesday. Will continue to have Pops for this, but then
it looks dry for Tuesday night into Wednesday.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1234 PM CDT Wed Aug 16 2017

An area of MVFR ceilings will persist over northeast Nebraska
including OFK with scattered to broken MVFR level clouds
potentially impacting OMA/LNK for a few hours this afternoon. Have
included a tempo group for the most likely time period. Otherwise
expect VFR conditions with winds turning out of the northwest and
persistently in the 10 kt range. There is a small chance for MVFR
cigs to build back into OFK late tonight but for now have kept a
VFR forecast.

For eclipse-area airports: Expect winds to turn out of the
northwest by mid afternoon. VFR conditions will be predominant but
may see 1-4 hours of bkn MVFR cigs this afternoon.




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