Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 300836
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
336 AM CDT SAT JUL 30 2016

.SHORT TERM...(today through Monday)
Issued at 335 AM CDT Sat Jul 30 2016

Early morning water vapor imagery and 30/00z upper-air analysis
indicate broad troughing from the Great Lakes into mid Mississippi
Valley, a high centered over Nevada, and a resultant northwest
mid-level flow regime present from the northern High Plains into
the mid and lower Missouri Valleys. Multiple weak perturbations
are embedded within this pattern, one of which is currently translating
through eastern Nebraska and western Iowa. At the surface, a ridge
axis stretched from the upper Mississippi Valley into the mid
Missouri Valley as of 07z with the primary baroclinic zone
situated to our south from the Ozarks into southwest Kansas.

Weak warm advection along a 30-kt southerly LLJ has fostered a
broken band of showers and thunderstorms from south-central South
Dakota into south-central Nebraska. Some of this activity could
drift southeast and potentially affect western portions of
our area this morning. Mid and high-level cloudiness associated
with the above-mentioned impulse tracking through the region could
limit radiational cooling and resultant fog formation toward
daybreak. We will monitor subsequent surface observations and
make a determination whether to add a mention to the grids.
Otherwise, the surface ridge axis will build to the east today
with some clouds and less-than-ideal mixing yielding highs in the
lower to mid 80s.

Tonight into Sunday, mid-level heights will build over the north-
central U.S. in advance of an amplifying upstream trough over
western Canada. A deepening lee trough over the High Plains will
encourage the northward advance of the front currently located to
our south. A southwesterly LLJ will strengthen tonight over the
central Plains, enhancing warm advection and isentropic ascent to
the north of the surface front. The 00z runs of the mesoscale
models are in reasonably good agreement in suggesting the
development of showers and thunderstorms within this regime across
the southern part of our CWA where we have maintained the highest
POPs. Some of this activity could linger into Sunday, namely over
southeast Nebraska and southwest Iowa, and this could potentially
impact daytime highs.

Sunday night into Monday, the western Canada system mentioned
above will lift northeast into central Canada in response to the
progression of the next system onto the Pacific Northwest Coast.
This will support the continued building of mid-level heights over
the north-central CONUS with a weak front associated with the lead
Canadian system sagging south through the northern Plains. A
southwesterly LLJ will once again strengthen Sunday night,
enhancing lift with thunderstorms possible along and east of the
Missouri River. The presence of PW values approaching two inches
and the potential for back-building storms could lead to
locally heavy rainfall, a situation that we will have to watch.
The nocturnal convection should drift deeper into Iowa on Monday
with the cessation of the nocturnal LLJ. Assuming early-day clouds
clear, a considerable warm up is anticipated with highs ranging
from mid 90s over our western counties to upper 80s in the far
east.

.LONG TERM...(Monday night through Friday)
Issued at 335 AM CDT Sat Jul 30 2016

The mid-level ridge will remain intact over the north-central U.S.
through Tuesday night before heights are temporarily suppressed by
the eastward progression of the above-mentioned Pacific Northwest
trough along the International Border. The associated surface
front will not move into our area until Thursday, with continued
hot conditions ahead of it on Wednesday. The front will remain in
the area through the end of this upcoming week, supporting cooler
high temperatures and a continued chance of precipitation.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1154 PM CDT Fri Jul 29 2016

There will likely be MVFR fog at all TAF sites between 09Z and
14Z, with a chance for brief IFR conditions at all sites.
Otherwise expect scattered clouds near FL050 during the daytime
hours, with scattered to broken high clouds through the TAF
period.


&&

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

$$

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



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