Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 171945
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
245 PM CDT Thu Aug 17 2017

.SHORT TERM...(Tonight through Sunday)
Issued at 245 PM CDT Thu Aug 17 2017

Quiet weather in the very short term, but a short wave moving
through the northern Rockies will move into northeast NE tonight,
and then toward the MO river by daybreak. This will spread
thunderstorm chances back into the region from northwest to
southeast tonight. As the wave moves through the area, there will
be good chance of showers/storms Friday morning, but most of the
activity should clear the area by Friday afternoon. Severe risk
does not look great overnight, no does there appear to be any
especially heavy rainfall. This sets us up for a spectacular
Friday night and Saturday with high pressure overhead and generally
clear skies. Highs Friday in the 83 to 88 range, then 83 to 91 on
Saturday.

Many of the model suites do indicate a wave wave moving out of the
central Rockies Saturday night. This could bring a small chance of
storms, but models are not in good agreement on where the best
chances exist. The Nam and EC models would keep the bulk of the
rain to the west of us, but GFS and Canadian would bring it
further east, and be potentially heavy according to the GFS, with
placement within some of the same areas that saw the very heavy
rains a couple of days ago. Will have some chance of storms in
there, but will wait for another couple of model runs to ramp up
pops just yet. There could be another weak perturbation Sunday
afternoon, which could help isolated storms develop mostly in the
afternoon. Highs Sunday 85 to 92. Afternoon heat index values,
while not oppressive, will be warmer than we`ve been used to,
reaching the upper 80s to mid 90s depending on location.

.LONG TERM...(Sunday night through Thursday)
Issued at 245 PM CDT Thu Aug 17 2017

Eclipse Weather Outlook

Both the GFS and Canadian models continue to show another weak
wave moving out of the Rockies with potential convective
development in our area Sunday night, along the nose of a low
level jet and possible developing warm front. The EC is also now
hinting at this, but just slightly farther north near the NE/SD
border. The GFS suggests that potentially heavy rainfall could
again be possible likely as a result of the developing east/west
boundary along I80. The Canadian is a little farther south with
with heavy rain placement, but still well within our area of
concern. Nevertheless, despite everyone`s wishes for a clear
night and clear skies on Monday, we`ll have to deal with some
potential storms and cloudiness early on Monday. The big
questions that we`re focusing on right now is whether the clouds
can clear enough Monday morning after the rain in time for the
eclipse. Partial eclipse roughly begins (give or take a couple of
minutes) in our forecast area around 1136 am, total eclipse begins
around 101 pm, and partial eclipse ends around 230 pm. Based on
today`s models, thinking that yes, we may see morning clouds and
storms, but there`s a decent chance they begin to scatter/break
up by late morning. Obviously, trying to predict a cloud forecast
with certainty for a 2 minute window that`s still 96 hours away is
a significant challenge. High temps Monday do rebound nicely into
the upper 80s to lower 90s, so even post eclipse activities will
be warm and humid with heat index values again in the mid to upper
90s especially along/south of I80.

Remainder of the extended has some pretty high precip chances
Monday night and Tuesday as a cold front moves into the area.
Tuesday night/Wednesday look generally OK. Thursday Could bring
additional thunderstorms to mainly eastern NE. Wednesday and
Thursday temps back into the upper 70s to lower 80s.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1150 AM CDT Thu Aug 17 2017

Generally look for VFR conditions through much of the period. Did
include a TEMPO group at all three locations later tonight or
Friday morning for MVFR visibilities with -SHRA. There is some
potential for TSRA, but at this point decided to leave out of the
TAFs until timing becomes more clear.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&

$$

SHORT TERM...DeWald
LONG TERM...DeWald
AVIATION...Miller



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