Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 221744

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1244 PM CDT Thu Mar 22 2018

.SHORT TERM...(Today through Saturday)
Issued at 333 AM CDT Thu Mar 22 2018

Amidst building mid-level heights, pronounced lower to mid-
tropospheric warm advection and isentropic upglide have fostered
bands of elevated convection from the NE Sandhills to south-
central IA as of 0730z. While much of the associated precipitation
is evaporating before reaching the ground, a few light showers are
being observed in areas of higher reflectivity. These forcing
mechanisms will linger into mid morning, and we will maintain
slight-chance PoPs across some of our southwest IA counties
through about 15z. Otherwise, a weak surface boundary analyzed
from near KONL to KSUX as of 07z may settle south today with the
warmest temperatures (i.e. lower to mid 60s) developing to it`s
south. Readings of 55 to 60 are expected to the north of the
boundary from northeast NE into west-central IA.

Tonight, the mid-level ridge axis over the Great Plains will
gradually weaken with the approach of an upstream short-wave
trough into the High Plains. The concurrent deepening of a surface
low over eastern WY will aid the development of a nocturnal low-
level jet, which in turn will hasten the poleward flux of an
increasingly moist air mass through the Plains. Best precipitation
chances through 12z Friday will remain to our northwest within the
zone of strongest low-level warm advection.

Friday into Friday night, the aforementioned High Plains short-
wave trough will progress through the northern and central Plains
and eventually to the east of our area by 12z Saturday. The
attendant surface low will track to our south, leaving our CWA in
the cold sector of the cyclone. Nonetheless, steepening mid-level
lapse rates coupled with increasing moisture content within the
warm-conveyor air stream will foster numerous showers on Friday
with embedded non-severe thunderstorms Friday afternoon into
Friday night south of I-80. The precipitation should end from west
to east late Friday night into Saturday morning with the passage
of the short-wave trough to the east.

.LONG TERM...(Saturday night through Wednesday)
Issued at 333 AM CDT Thu Mar 22 2018

Dry conditions will be short-lived as precipitation chances return
to the forecast Saturday night into Sunday in association with a
low-level warm advection pattern developing across the area. It
appears that we will remain in a wet pattern into the middle of
next week ahead of a slow-moving, multi-stream trough that will
edge east from the Interior West into the Great Plains. Highest
precipitation chances are focused in the Monday to Monday night
time frame along a surface cold front which will advance south
through the area. An increasingly moist and unstable air mass is
forecast to develop within the warm sector ahead of the front and
a few strong to severe storms appear possible Monday afternoon
into evening across southeast NE into southwest IA. Given that we
are still five days away, this scenario could certainly change.


.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1238 PM CDT Thu Mar 22 2018

VFR conditions will prevail through this evening. Increasing low
level moisture advection after midnight though will result in
deteriorating conditions through Friday morning. Expect MVFR cigs
to prevail then at all terminals btwn 12z-18z Friday. At this
point have decided not to include any mention of RA as areal
coverage at that time is still in question.




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