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Area forecast discussion
National Weather Service Omaha/valley NE
311 PM CST Fri Dec 9 2016

Short term...(tonight through monday)
issued at 310 PM CST Fri Dec 9 2016

Early-afternoon water vapor imagery and 12z upper-air analysis
revealed low-amplitude cyclonic flow east of The Rockies with an
upstream short-wave trough approaching the Pacific northwest
coast. This short-wave trough will move onshore tonight and
eventually reach the northern plains by Sunday. In the low
levels, mesoanalysis placed a cyclone along the Cheyenne Ridge
with this feature eventually developing south through the Central
High plains, along a southward-moving cold front.

Mosaic radar data as of 21z indicate a broken band of weak
reflectivity across eastern NE into southwest Iowa with a recent
report or flurries or light snow at Albion. A few flurries will
remain possible into this evening, mainly across northeast NE
within a corridor of modest isentropic upglide.

Late tonight into Sunday, low-level warm advection and isentropic
ascent (best seen on the 285-295k Theta surfaces) will strengthen
in response to the progression of the above-mentioned short-wave
trough into the northern High Plains. A resulting band of snow
will materialize and spread east across portions of the mid
Missouri Valley before shifting east of the region by Sunday
night. The best chance of accumulating snow will be across the far
northern part of the forecast area where one to three inches are

On Sunday, amplification of the mid-level flow pattern
will occur over the upper Mississippi Valley, which in turn will
promote the deepening of a surface low to our southeast. Some
light snow will be possible, mainly across the northeast part of
the forecast area where forcing for ascent will be stronger.
Farther south, a warm nose evident in forecast soundings in the
800-750-mb layer could contribute to mixed-phase precipitation
across portions of southeast NE and southwest Iowa prior to ending.

It appears that we will see a reprieve from the seasonably cold
temperatures this weekend into Monday with afternoon readings
warming into the 30s across our central and southern counties.

Long term...(monday night through friday)
issued at 310 PM CST Fri Dec 9 2016

Another Arctic air mass will overspread the mid Missouri Valley
late Monday and will likely remain entrenched through the
remainder of the week. This will result in much-below-normal
temperatures with a chance for light snow during the middle to
late part of the week. The 12z run of the European model (ecmwf) does suggest the
potential for a more significant snowstorm next Friday, though
this solution is not supported by the deterministic GFS or gefs
ensemble data.


Aviation...(for the 12z tafs through 12z Saturday morning)
issued at 1138 am CST Fri Dec 9 2016

VFR conditions will prevail at koma and klnk through the forecast
period. VFR conditions will be at kofk until 10/15z when low clouds
move into northeast Nebraska. Ceilings at kofk are expected to
become MVFR at that time.


Oax watches/warnings/advisories...


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