Scientific Forecaster Discussion
fxus63 kgid 160526
Area forecast discussion
National Weather Service Hastings NE
1126 PM CST Fri Dec 15 2017
Short term...(this evening through saturday)
issued at 237 PM CST Fri Dec 15 2017
Afternoon fire danger...
the nice warmup this afternoon is
resulting in near critical fire danger across our southwestern
zones with relative humidity values of 15 to 25 percent and winds around 15 to 20
mph. The wind will quickly die down this evening and relative humidity values
will climb as we cool.
Tonight...a light southwest breeze tonight will help to keep
temperatures a bit warmer than last night by a few degrees, but
still below freezing in all areas ranging from 21 to 29.
Saturday...this will be the nicest day of the weekend as a cold
front will track through, but the cold air should lag a little
behind the front making Sunday the colder day. Many areas,
especially south of I-80 could see highs in the 50s again on
Saturday. The cold frontal passage should be dry.
Long term...(saturday night through friday)
issued at 237 PM CST Fri Dec 15 2017
There will be a cool down on Sunday behind saturday's cold front
and then another nice warm-up Monday into Wednesday, before the
bottom falls out and we get below normal cold for Thursday and
Friday with at least some chance for snow.
Saturday night...am going dry for now, but this is one period to
watch with precipitation areas just missing US to the northwest
and southeast essentially splitting our area. There is a chance of
freezing drizzle over the Nebraska sandhills that will be a close
call on our northwestern zones and a chance for light rain just
southeast of our Kansas zones.
Sunday...a cool sfc high will slide across the area resulting in
highs in the upper 30s to lower 40s, but the wind will be light so
it shouldn't feel too bad out there.
Monday through Wednesday...the polar jet heads back north of our
forecast area although we should begin to see significant digging
of the upper jet into the western states by Wednesday. This will
be a warm pattern ahead of the developing western storm system.
Forecast models continue to be in good agreement on mainly 50s for
highs with dry conditions.
Thursday...this is really when we start to see a larger upper
pattern change that we have been talking about in recent days.
There will be deep digging trough across the western states with
cold air spilling south through the northern and Central Plains.
Confidence is high in a good blast of cold air that will send US
below normal for temperatures for at least a few days, which will
be very noticeable after our recent weeks of warmth. The big
question will center around snow chances. The 00z and 12z European model (ecmwf)
both continue to be rather bullish with a light snow event for
much of our forecast area on Thursday, especially Nebraska zones.
However, the 12z European model (ecmwf) ensembles are generally showing less snow
than the deterministic run, although most show at least a little
light snow. The 12z GFS really gives US little if any snow. At
least right now am not seeing anything that says big snow out of
this system, but a little light snow could be enough to stick
through Christmas giving US some white Christmas potential given
the expected cold to follow.
Friday...confidence is low on temperatures as I believe they are
more likely to be colder than what we are currently forecasting
given this overall new pattern that we will be in. Do not be
surprised if these highs get lowered with future forecast updates.
Already lowered them several degrees below superblend guidance.
Aviation...(for the 06z kgri/kear tafs through 06z saturday)
issued at 1114 PM CST Fri Dec 15 2017
VFR conditions are expected through the period with a dry cold
front bringing a shift in winds during the afternoon hours
tomorrow. Expect steady southwesterly winds to continue to
diminish through the overnight hours...becoming light and variable
in the area of a surface trough by the early morning hours.
Expect the leading edge of an approaching cold front to reach both
terminals just after noon...bringing a shift in winds to the north
or northeast by late afternoon. Little more than a few passing
mid or high level clouds are expected with the passage of this