Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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800
FXUS63 KOAX 310831
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
331 AM CDT SUN JUL 31 2016

.SHORT TERM...(today through Tuesday)
Issued at 330 AM CDT Sun Jul 31 2016

Early-morning water vapor imagery and 31/00z upper-air analysis
indicate a trough over western Canada, downstream ridging over the
northern High Plains and a broad, low-amplitude trough over the
Great Lakes into mid Mississippi Valley. Despite the building
mid-level heights, low-level upslope flow and strengthening warm
advection along a nocturnal LLJ have sustained a bowing MCS,
which is moving through north-central Nebraska as of 08z. Farther
to the south, warm advection is fostering secondary MCS formation
over north-central Kansas into south-central Nebraska.

Latest short-term model guidance suggests that the former, bowing
MCS will gradually decay while continuing east-southeast across
the northern half of our CWA this morning. Gusty winds will remain
possible along the leading edge of the system cold pool. Meanwhile,
the secondary MCS should remain largely in Kansas, though its
northern extent could impact some of our southeast Nebraska
counties with small hail and gusty winds this morning.  Residual
effects of clouds and convective outflow will likely have the
greatest impacts on our central and eastern counties where we
have lowered afternoon highs.

Tonight, conditions appear to be coming together for a potential
heavy rainfall event over western Iowa. A nocturnally strengthening
LLJ will promote the poleward flux of an increasingly moist air
mass (i.e. PW values of around two inches), as well as enhancing lift
atop a shallow front developing north into the mid Missouri
Valley. The setup will favor back-building/training storms and the
potential for a narrow swath of heavy rainfall. Some of this
convection could linger over our western Iowa counties early
Monday before shifting east of the area. Highs should be
generally in the mid 80s.

Monday night into Tuesday, a mid to upper-level low will pivot
northeast through central Canada with an associated surface front
settling southeast through the northern Plains into the mid
Missouri Valley. This is a departure from previous model runs,
which suggested hot conditions areawide on Tuesday. Now, it
appears that high temperatures may range from the upper 80s north
to mid 90s south, ahead of the front. This boundary will also
serve as a focus for isolated to widely scattered storms during
that time frame.

.LONG TERM...(Tuesday night through Saturday)
Issued at 330 AM CDT Sun Jul 31 2016

As mentioned above, it now appears that a front will stall across
the area Tuesday into Tuesday night before washing out by
Wednesday. A strong short-wave trough will progress from the
northern Intermountain Region into south-central Canada by
Wednesday night, driving another cold front into the area on
Thursday. This boundary will also stall over the region late this
upcoming week beneath building heights aloft. As such, we will see
a continued chance of showers and thunderstorms with the warmest
temperatures around mid week (i.e. lower to mid 90s), with highs
then settling back into the 80s by the end of the work week into
next weekend.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1141 PM CDT Sat Jul 30 2016

An area of thunderstorms will move southeast from western South
Dakota into eastern Nebraska between 10Z and 18Z. MVFR cigs/vsbys
will accompany any storms, but brief IFR conditions are likely.
Outside of storms, VFR cigs near FL060 are forecast to overspread
eastern Nebraska between 06Z and 10Z with southeast winds near
10kt. VFR conditions are forecast after storms pass after 18Z when
southeast winds increase into the 13 to 20kt range through the
afternoon.


&&

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

$$

SHORT TERM...Mead
LONG TERM...Mead
AVIATION...Dergan



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