Area Forecast Discussion
Issued by NWS Goodland, KS
FXUS63 KGLD 020958
Area Forecast Discussion
National Weather Service Goodland KS
258 AM MST Fri Dec 2 2016
.SHORT TERM...(Today through Sunday night)
Issued at 257 AM MST Fri Dec 2 2016
Main forecast concern will be chance of precipitation tonight.
Satellite showing an amplified and active flow from the Pacific into
North America. Broad trough encompasses much of the country as a
complex upper trough begins to deepen and split over the western
portion of the country.
Models started out well at mid levels with the Gfs, Ecmwf, and
Canadian doing a little better. Models started out fine on the low
level thermal field but were a little too cold. Overall the Gfs,
Canadian, Ecmwf, and Sref were starting out the best.
Today/tonight...cloud cover has been slower to increase. Now it
looks like the thickest cloud cover will not occur until the
afternoon. As a result of the slower arrival, overnight temperatures
have dropped more than previously expected. All in all the far
eastern section should be able to warm up the longest. Made slight
adjustments based on the latest data.
For tonight the newer data is slower and further south with the lift
and deeper moisture. Theta-e lapse rates are not very good again.
Area is also on the wrong side of the jet. Also the mid level
lift/frontogenesis is very organized. I went ahead pulled the pops
further south with the highest pops in the extreme south and also
having the highest pops after midnight. It only looks .01 or .02 of
qpf with the phase being all snow.
Saturday/Saturday night...With the slower arrival of tonights
precipitation, the precipitation is expected to linger into the
morning with very light amounts. Due to cloud cover and some cold
air advection, temperatures will be cooler than todays. What the
blend gave me looks reasonable. The nighttime forecast also looks in
good shape and did not change.
Sunday/Sunday night...the next question is how much do we warm up.
Should be plenty of sun and deep/dry air mass in westerly flow aloft.
Surface winds will be southwest to west and then shift toward the
south in the afternoon as the lee trough starts developing. High
temperatures look to range from the middle 40s to the lower 50s
which will feel very warm compared to what is coming in.
.LONG TERM...(Friday night through Thursday)
Issued at 108 PM MST Thu Dec 1 2016
Going into the extended period...the Tri State region will see
two different systems set to affect portions of the CWA. The first
system involves a cutoff low that dives well into northern Mexico
by Friday night. A shortwave does move in tandem slowly with this
low over the northern plains. Strong surface ridging is in place
over a good portion of the Central/Northern plains with the
arrival of these systems. This ridging will allow for blocking of
any major moisture to really work up into the CWA...w/ only the
northern fringe scraping portions of the southern CWA before
shifting east by Saturday morning. With model qpf only pointing
towards a few hundredths of an inch at best...temps in the 20s
will only mean a slight chance for light snow of a few tenths of
an inch at best. The focus for any accum will be south of
Interstate 70 and east of the KS/CO border.
The second of the 2 systems is set to affect the CWA over a 36-42 hr
period...current depicted in latest models from next Monday night on
thru the morning hrs of Wednesday. Models bring this winter wx maker
in as an upper low/arctic front combo. There have been model
discrepancies on timing/strength of this system over the past few
days in terms of snowfall potential. Decent confidence that the CWA
will definitely see a profound shift in temperatures...setting the
area into more of a winter pattern. A shortwave working around the
base of this upper low/trough works thru the CWA. Latest GFS has
more of a north-south pattern set up for the precip that
occurs...while the trough in the ECMWF digs further south and precip
with this has more of an west to east sweep thru the CWA. These
differences are allowing for different snowfall totals. Surface
ridge that will work in behind this exiting system does play a role
late in the period with any easterly fetch that sets up providing an
upslope component that could enhance snow totals...especially over
NE CO. For now the CWA will be looking at an ~1-3 inch potential
based on model consensus...with higher amounts north of I-70. With
several days ahead before this system arrive any change in
track/timing could have these numbers adjusted significantly.
While the snowfall expected for the CWA still has an uncertainty
factor to it...what is certain for the CWA is that the area will see
overall temps drop sharply thanks to the passage of the arctic
front. Before its passage...CWA will highs range in the 40s for Sat-
Mon...then shift down to mainly the 20s for Tues-Wed. The arrival of
the surface ridge going into Thursday will allow for a rebound back
into the 30s. Overnight lows will see 20s before fropa...down to low
teens and single numbers above zero for Tuesday and Wednesday nights.
Accompanying these colder temps overnight will be windy conditions
that will bring wind chill readings as low as -5 to -10 below in
some locales for tues/wed nights.
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1000 PM MST Thu Dec 1 2016
For KGLD and KMCK, vfr conditions expected through the period.
Both terminals will see a light west wind gradually veer to the
northwest by mid to late morning Friday then steadily veer to the
north, east and south through the remaining taf period at speeds
around 5kts. A weather disturbance moves across the area from the
southwest late tomorrow afternoon through the rest of the taf
period bringing increasing cloudiness.