Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 260455
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1155 PM CDT THU AUG 25 2016

.SHORT TERM...(tonight through Sunday)
Issued at 300 PM CDT THU AUG 25 2016

Precipitation chances and the potential for flooding and some severe
weather are the primary forecast concerns.

Manual 12z upper-air analysis revealed a positively tilted long-wave
trough from central Canada to the southwestern U.S. with a sub-
tropical high over the Southeast. A resultant southwesterly mid-
level flow regime was present over the central Plains with an
embedded short-wave trough currently de-amplifying to our
northeast. At the surface, early afternoon mesoanalysis placed
the primary baroclinic zone from the Ohio Valley west-southwest
through northern Missouri and east-central Kansas into the Texas
Panhandle.

The precipitation shield present earlier today over southeast
Nebraska and southwest Iowa has shifted to the east of the area
with only light showers or sprinkles observed over south-central
Nebraska and north-central Kansas as of 19z. Some of this activity
could make it into our area late this afternoon or early evening,
though no more than sprinkles are anticipated. Another weak
short-wave trough is forecast to track across Kansas overnight,
supporting an increased chance of showers and thunderstorms over
southeast Nebraska and southwest Iowa.

On Friday, the surface front currently stalled to our south will lift
north into the area within a strengthening low-level warm
advection regime. This forcing coupled with increasing amounts of
moisture and instability will support the south-to-north
development of showers and thunderstorms through the day. A few
strong to severe storms will be possible during afternoon into
evening, with the highest probability of occurrence over southeast
Nebraska and southwest Iowa where a favorable overlap of
"sufficient" shear and instability is forecast to reside.
Increasing clouds and areas of convection should hold highs in the
70s.

Friday night, a short-wave trough (located over the Great Basin this
morning) will translate through the mid Missouri Valley along with
an associated surface front, focusing numerous showers and
thunderstorms.  Recent heavy rainfall over portions of east-central
and southeast Nebraska and southwest Iowa has moistened the soil
and set stage for considerable run off with any subsequent
precipitation.  As such, we will be monitoring the situation for
flash flood potential as finer-scale details become more clear.

Rain chances should diminish from west-to-east on Saturday as the
short-wave trough accelerates northeast into the Great Lakes ahead
of a powerful polar-branch trough moving across the northern
Plains. Decreasing clouds should allow for slightly warmer
temperatures in the upper 70s to lower 80s.

Saturday night into Sunday, weak low-level warm advection may be
sufficient to initiate isolated to widely scattered showers and
thunderstorms, mainly across southern portions of the area. Highs
will be dependent on the degree of cloudiness and precipitation
with readings in the mid 80s possible.

.LONG TERM...(Sunday night through Thursday)
Issued at 300 PM CDT THU AUG 25 2016

The 12z medium-range guidance indicates that a mid-level ridge
will become established over the north-central U.S. during the
early to middle part of this upcoming week which will yield high
temperatures in the 80s. While the primary low-level baroclinic
zone will remain confined to our north, model guidance continues
to suggest a low-probability chance of showers and thunderstorms
through much of the extended range.

&&

.AVIATION...(06Z TAFS for KOFK...KLNK and KOMA.)
Issued at 1153 PM CDT THU AUG 25 2016

VFR conditions initially, with shower chances increasing at
KLNK/KOMA by 18-21z, then about a 3-5 hour chance for
thunderstorms 20-02z. Just shower chances at KOFK by 21z and
beyond if at all. Cloud bases eventually thicken to 8000-10000
feet through midday, and eventually to MVFR by 00z and beyond
toward the end of the TAF period.

&&

.OAX Watches/Warnings/Advisories...
NE...None.
IA...None.
&&

$$

SHORT TERM...Mead
LONG TERM...Mead
AVIATION...DeWald



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