Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Hastings NE
146 am CST Friday Nov 27 2015
issued at 140 am CST Friday Nov 27 2015
Updated the forecast overnight to include all snow for the rest of
tonight into Friday as reports from Osborne and Mitchell counties
indicate a complete changeover to snow.
Short term...(this evening through friday)
issued at 336 PM CST Thursday Nov 26 2015
Aloft: a +tilt trough extended from Hudson Bay SW to an upper low
over the intermountain west. SW flow will remain through tomorrow... but
the trough NE of the low will remain progressive over eastern Canada
into the Great Lakes. A shortwave ridge will move through here
tonight in SW flow. The associated subsidence along with the
progression of the trough bring an end to most of the precipitation.
Surface: an Arctic air mass was in place with the front well S and
east of the forecast area. Strong 1042 mb high pressure was over Montana.
This high will slide into the northern plains through tomorrow and expand
deeper into the region.
The steadier precipitation has ended for most areas giving way to more
showery precipitation. Rather than go into all the details...we will let
the forecast speak for itself.
We made multiple calls to County dispatch ctrs from York to
Beloit. Bottom line is we did not get the expected ice over the
warning area. So in coordination with oax/top it has been
downgraded to an advisory.
The majority of the advisory from Alma-Grand Island-Fullerton
westward has been cancelled.
We are in a lull in precipitation at this time. However..regional radar showed
expanding precipitation shield over central and SW Kansas. The northern fringe of
that was already moving into portions of north-central Kansas and will continue
to overtake the southeast 1/3 of the forecast are through tonight.
Temperatures are now sub-freezing over the entire forecast area. So believe most
of this precipitation will fall as freezing rain or sleet...mainly along and
S of a line from Plainville Kansas-Hebron Nebraska. This is where we think
there is potential for some hazardous icing through midnight.
So while we continue the advisory to cover this...it is likely that
the northern fringe of the advisory may see little or no precipitation. It was
kept as a buffer just in case. If a little precipitation falls north of the
Plainville-Hebron line it will be cold enough for snow.
We have kept some minor chances for a touch of snow or sleet S of
Highway 6 down into north-central Kansas tomorrow. However...this may be
overdone. It's in there just for uncertainty sake to cover
possible brief interaction with the frontal and of precipitation.
Long term...(friday night through thursday)
issued at 336 PM CST Thursday Nov 26 2015
A cold surface high settles into the area Friday night.
Temperatures will drop to the teens for much of the forecast area.
The main question will be whether the surface high is strong
enough to push the light snow out of the forecast area. There is
still a little bit of a weak upper level wave that moves across
and have kept snow mainly across north central Kansas. Late Friday
night there is a little bit of drying in the dendritic layer and
there could be a little freezing drizzle possible in the
There is an upper level low in The Rockies that sends out a few
pieces of energy over the weekend then moves into the plains early
next week. Models have some differences in timing with the waves
over the weekend. By the time the upper low moves into the plains
there are a few differences...but they are less.
Saturday into Sunday all of the models have mainly on and off
precipitation across the forecast area. Have kept mainly low
chances for precipitation. The precipitation type is also in
question. The surface temperatures would lead toward mainly
snow...especially during the night when it is cooler...but the
problem is that there is a warm layer aloft and some in and out
moisture in the dendritic layer. Have kept some snow in there for
the most part...but with the warm layer and dry dendritic layer at
times...there could be either light freezing rain or freezing
drizzle at times. There could even be some sleet at times...but
for now have kept the approach a little on simple side.
The upper low starts to move out of the