Area Forecast Discussion
Issued by NWS Goodland, KS
FXUS63 KGLD 240316
Area Forecast Discussion
National Weather Service Goodland KS
816 PM MST Mon Jan 23 2017
Issued at 816 PM MST Mon Jan 23 2017
Update to forecast issued to acct for lack of cloud cover over the
CWA. With the exception of northern portions of Yuma County in NE
CO...the remainder of the CWA is clear. Thicker cloud cover still
remains off the west...with a slow trend east off the Front
Range. Now looking for at least mostly cloudy conditions to set
in by midnight. The lack of clouds currently is allowing temps to
drop CWA-wide. If the strong radiational cooling effects continue
under clear skies...may have to drop forecasted overnight
lows...but will wait a couple rounds of obs towards next ESTF
.SHORT TERM...(This afternoon through Tuesday)
Issued at 212 PM MST Mon Jan 23 2017
SW flow is in place aloft over the Central High Plains with several
weak shortwaves rippling through the mean flow. Large scale
trough is in place over the western US. At the surface lee trough
has deepened and shifted eastward with a warm front near
Tonight-Tuesday: A cold front will drop south over our CWA late
tonight as the large scale trough in the west shifts eastward into
the plains. The closed upper low that develops will be just north of
our CWA, and despite variances in this system impacts will be
limited over our CWA.
Easterly low level flow along/behind the cold front tonight will
bring with it increasing BL moisture and the potential for freezing
fog/freezing drizzle. This ultimately may be the higher impact
weather type for this event for our CWA and would be confidence to
the morning hours.
Large scale ascent will increase late tonight and there is some
elevated instability that could support a few showers after 06Z.
There is a dry layer between H85-H7 that lowers confidence in
measurable precipitation. Better chances arrive during the day
Tuesday (mainly in our north), but even then the precipitation
would be light. Current trend in both GFS/ECWMF is to favor a
track far enough north to even limit measurable potential during
the day Tuesday. An added layer of complication is a warm nose
highlighted by Tw above 3C through midday Tuesday. If saturation
of the mid level dry layer were to occur this may support mainly
rain rather than snow or freezing precip particularly in the 06Z
through 15Z timeframe as better CAA may be delayed until 18Z. Due
to the very light nature of any precip that occurs, I chose to
keep the message simple regarding rain/snow transition. If snow
accumulations do occur (mainly north) they should be below one
inch through Tuesday afternoon.
CAA will be occurring through the day Tuesday from the north, and
this (in addition to possible stratus) complicates high temperature
potential and may result in falling temps during the afternoon
north of I-70. Adjustments were made to highs to lower them
slightly from previous forecast.
.LONG TERM...(Tuesday night through Monday)
Issued at 204 PM MST Mon Jan 23 2017
Forecast concerns will be precipitation/wind at the beginning of
this period followed by temperatures. Satellite showing an
amplified pattern from the Pacific into North America. At jet
level...the Canadian and Ecmwf were doing a little bit better on
the strong jet near and to the southwest of the area. At mid
levels...models started out fine with only subtle differences.
Tuesday night...strong jet is to the east and south of the area.
The 00z Ecmwf and 12z Canadian continued to be the slowest and
furthest south of the upper low. The 12z Ecmwf however came in
further north closer to the the other output. The brunt of this
system should be felt outsider our area.
Even with the system track not in a favorable position to produce
significant precipitation, in this case snow, there is enough
moisture and lift with okay but not great theta-e lapse rates that
I cannot rule out some light precipitation occurring this
period. So stuck with the slight chance to low chance pops the
builder gave me and blended/serpiscd with my neighbors.
Incoming cold air and the winds will be the main issues for this
period. Gradient and downward motions will still be tight/rather
stronger during the night, especially in the first half. With that
and collaboration populated the wind grids with Consmos.
Wednesday/Wednesday night...Any precipitation should be done by the
beginning of this period so removed the slight chance pops from the
northeast portion of the area that the builder gave me. There is
still enough of a gradient along with some downward motion to keep
windy conditions going through most of the day. Temperatures will be
colder and what the forecast builder gave me looks reasonable and
did not change.
During the night the surface ridge moves in and the winds will drop
off. However models are indicating that there will be increasing mid
and high level cloud cover. I did trend temperatures down slightly
because of all this.
Thursday...Northwest winds continue but will be not as strong as the
day before. Some warming occurs and could not argue against what the
blender gave me.
Thursday night through Monday...open wave in northerly flow aloft
moves through Thursday night into early Friday. After that, strong
ridging builds over the western portion of North America leaving the
area in northerly flow aloft. On Sunday this ridge is flattened and
pushed a little west as a shortwave trough moves into the north
central portion of the country on Monday.
It does look dry through the period, and that is reflected in what
the builder gave me. There looks to be a gradual warming trend
through the period. However will have to be careful that this
northerly flow will not sneak some colder air into the region.
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 433 PM MST Mon Jan 23 2017
For KGLD...VFR conditions expected thru 07z Tuesday w/ mainly
high clouds. 07z-19z MVFR/VFR mix with ceilings bkn060 down to
bkn020 after 16z. Visibility down to 4sm at times in freezing
drizzle and fog as well. From 19z onward...VFR conditions. As low
pressure passes over the region...winds go from ESE around 10kts
to WSW by 03z. By 14z Tuesday...winds NW around 10-15kts. Gusts
20-30kts after 19z.
For KMCK...VFR conditions w/ scattered high clouds thru 08z
Tuesday. 08z-23z...MVFR/IFR mix as storm system moves over the
region. Looking for visibility 1-4sm in freezing drizzle and
fog...and ceilings ranging from ovc003-015. By 23z VFR
conditions. Winds ESE to ENE around 10kts thru 12z Tuesday...then
NNW 5-15kts with gusts 20-30kts from 18z onward.