Scientific Forecaster Discussion
fxus63 kgid 171721
Area forecast discussion
National Weather Service Hastings NE
1121 am CST sun Dec 17 2017
issued at 646 am CST sun Dec 17 2017
Updated to add some patchy drizzle to northwest portions of the
forecast area. As mentioned previously, the hrrr has been showing
this potential for several runs, and ceilings have dropped
considerably at several locations just to the west.
Temperatures should slowly rise in these areas this morning, so I
do not expect freezing drizzle to be an issue.
Short term...(today and tonight)
issued at 217 am CST sun Dec 17 2017
Radar mosaic shows scattered rain showers across central Kansas
slowly moving northeastward associated with a midlevel wave
apparent on water-vapor imagery. This activity was initially
expected to stay southeast of the forecast area, but it appears
that slower timing of the frontal passage will allow it to creep
into southeastern parts of the area (southeast of a line roughly
from Phillipsburg, Kansas to Geneva, ne). Temperatures in these areas
are currently in the mid 30s. With a fairly deep surface warm
layer, I expect precipitation will initially be all rain, but
could transition to sleet or snow as evaporative cooling occurs.
Impacts will be minor, but sleet and snow could produce a few
slick spots before temperatures warm up by mid morning. Hrrr and
rap show that precipitation should push east of the area by 9 or
The other forecast concern in the near-term is the threat for
drizzle or freezing drizzle across western and west-central
Nebraska. Most of this would remain west of the forecast area, so
I have left it out of the forecast for now. That said, hrrr
soundings show that it could briefly approach the Gothenburg and
Lexington areas around 6-7am. Luckily, temperatures are also in
the mid 30s in the areas that would be the most favorable for
drizzle. This will be monitored closely over the next few hours.
High temperatures today will be much cooler than previous days,
largely thanks to persistent cloud cover. High temperatures are
expected to reach the upper 30s to mid 40s. Lows tonight should
drop into the mid 20s as skies gradually clear.
Long term...(monday through saturday)
issued at 217 am CST sun Dec 17 2017
Westerly winds at the surface and aloft will make Monday
significantly warmer than today, with high temperatures in the mid
A trough will pass to the south of the area on Tuesday. This will
have little impact on the weather other than shifting winds to
the north and making for high temperatures 5-7 degrees cooler than
We will have one more nice warmup on Wednesday before a strong
cold front sweeps through the area for Thursday.
Models have trended back considerably on precipitation amounts
and chances with this cold front, especially the GFS. What was
looking like a high probability for accumulating snow yesterday,
now looks like much of the forecast area could remain snow free.
Nevertheless, there is still plenty of time for this to change
One thing that didn't change is the punch of cold air that is on
the way. Gusty north winds will push wind chills into the single
digits during the day on Thursday. High temperatures in the
following days will only reach the 20s to low 30s, and low
temperatures will be in the single digits and teens.
Other than the cold, the forecast remains quiet Friday and
Saturday. Don't expect a significant warmup before Christmas,
though. The gefs and Euro ensembles both keep plenty of cold air
in the area next Sunday into Monday.
Aviation...(for the 18z kgri/kear tafs through 18z monday)
issued at 1115 am CST sun Dec 17 2017
The terminals are in fairly clear skies in between MVFR clouds to
the west, north and east. The lower clouds are forecast to erode
through the afternoon, with little impact expected for kear and