Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Omaha/valley NE
523 PM CST Monday Dec 9 2013
Aviation...00z tafs for koma...klnk and kofk. VFR conditions
prevail through the period. Middle clouds at 8-15000 feet will move
in from the northwest by 02-15z. Could see a lower deck around
4000 feet at kofk-koma from 05-15z. Will also see a wind shift
from south to the southwest...and then west southwest..increasing
to 12 to 14 knots...with gusts up to 20-25 knots. Gusts may
diminish by 10-12z.
Previous discussion... /issued 342 PM CST Monday Dec 9 2013/
Short term...tonight through Thursday.
Temperatures will be the primary short term concern...then light
snow and flurries mainly Tuesday night.
Despite the sunshine and southwest winds...after a very cold
start...most locations only warmed into the 10 to 15 degree
range. Tonight...a 45 to 50kt low level jet is expected to develop
and this will result in warm air advection ahead of a shortwave
trough moving through Minnesota. Some of the high resolution models
are hinting at some flurries with any clouds that move in behind
the front. The cold air advection behind the wave is short-
lived...as another shortwave is affecting the area already Tuesday
afternoon into Tuesday night with some flurries and light snow.
This system appears to have a little more moisture will it and a
decent amount of cold air advection. The frontogenesis is not as
robust as advertised yesterday...however there is some right
entrance region jet enhancement...Omega...and favorable dendritic
temperatures. Do have light snow accumulations with this fast
moving system Tuesday night. With the snow cover...trended with
cooler than guidance. Should see temperatures moderate as the
winds pick up tonight and have highs Tuesday in the 20s.
Wednesday still looks cold with highs in the teens to lower 20s
and Thursday even warmer with highs in the 20s to lower 30s.
Long term...Thursday night through Monday.
Mainly northwesterly flow will persist across the central US through
the period...with a few embedded waves and some temperature
fluctuations. One such wave is prognosticated to move across the plains on
Friday/Saturday...bringing a chance of precipitation mainly south of
our area on Friday night...but also likely bringing increasing
clouds. Have kept probability of precipitation out of the forecast...per model trends...but
could see potential for a few flurries on Friday night...especially
in the eastern County Warning Area...as upper-level trough intensifies after it
passes US by. After a brief shot of cold air behind that
wave...temperatures are prognosticated to moderate by varying degrees on
Sunday/Monday...before another wave drops out of the Dakotas and
delivers another shot of cooler air /though not nearly as cold as
recent cold air shots/. Models vary quite a bit on how much warming
will take place on Sunday/Monday...but with a snow cover...have
played toward the cooler side for now and undercut blended guidance
a few degrees.