McCook, Nebraska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

556
FXUS63 KGLD 181030
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
330 AM MST Sat Jan 18 2025

.KEY MESSAGES...

- Light snowfall accumulations generally west of Highway 25
  today. Winter Weather Advisory continues through 2 PM MST for
  Cheyenne/Kit Carson counties in Colorado.

- Extreme Cold Watch continues for the entire area late this
  afternoon through Tuesday morning as wind chills of -15 to
  -30 degrees are forecast, mainly during the overnight hours.

- Light snowfall returns to the area late Sunday night through
  the day Monday with accumulations generally under one inch.

- Temperatures are forecast to rise above freezing Tuesday with
  near normal temperatures forecasted.

&&

.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 330 AM MST Sat Jan 18 2025

Today-tonight...snowfall chances slowly decrease from north to
south today as some drier air moves in. Snowfall chances remain
generally west of Highway 25 at 20%-60% with additional
accumulations of a trace to half inch. With northerly winds gusting
25 to 30 mph, some blowing snow and reduced visibilities will be
possible. The Winter Weather Advisory for Cheyenne and Kit Carson
counties continues through 2 PM MST. Tonight, no precipitation is
currently forecast.

High temperatures are forecast to be in the middle teens to lower
20s. Low temperatures are forecast to be in the single digits above
and below zero. Overnight wind chill readings are forecast to fall
into the 10 below to 20 below zero range. An Extreme Cold Watch is
in effect late this afternoon through. Presently, most of the area
generally west of Highway 25 is flirting within a few degrees of
hitting our -15F threshold for a Cold Weather Advisory. Will let the
day shift get another look at temperature and wind data before
deciding who if anyone goes into a Cold Weather Advisory.

Sunday-Sunday night...dry weather is forecast during the day, ahead
of another weather system that brings a 20%-50% chance of light snow
to areas generally west of Highway 25 after midnight with little if
any accumulation.

Presently, high temperatures are forecast to be in the middle teens
to lower 20s. There continues to be some variance in various model
forecasts with some colder and some warmer than the current
forecast. NBM model spread in temperatures has decreased from 7 to 8
degrees yesterday to 3 to 6 degrees this morning. Low temperatures
are again forecast to be in the single digits above and below zero
with wind chill readings in the 5 below to 20 below zero range. Will
be continuing with the Extreme Cold Watch for the time being.

Monday-Monday night...Sunday nights weather system continues moving
south during the day with 20%-40% chances for light snow generally
south of Interstate 70. Accumulations at this time a few tenths to
near an inch. With some northwest winds occasionally gusting in the
25 to 30 mph range, some blowing snow will be possible. High
temperatures are forecast to range from the single digits to lower
teens across far eastern Colorado to the middle teens elsewhere. NBM
temperature spread is about 5 to 7 degrees, so some further tweaks
up or down will be possible. Dry weather with rapidly decreasing
clouds are forecast during the night. Low temperatures are forecast
to be in the single digits below zero with wind chill readings
generally 15 below to 25 below zero. The Extreme Cold Watch
continues for now.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Issued at 124 AM MST Sat Jan 18 2025

The period will begin with an upper-level trough axis running from
the Great Lakes to around the Baja California area. A high pressure
system will be moving over northern California from the Pacific.
Throughout the day Tuesday, this high will move farther inland, but
another Alberta Clipper will weaken the high and prevent it from
settling over the Great Plains. Around 0Z Thursday, the upper-level
trough axis will be sweeping through the area. About that same time,
another high will be moving over the west coast, moving the trough
out of the High Plains by Friday morning.

Down at 850 mb, a high will be extending from the Great Basin/Four
Corners area into northwestern Texas. This will promote warmer
temperatures on Tuesday, likely in the mid 30s to near 40. Overnight
temperatures Tuesday, due to some light cloud cover and 5-10 kts
mixing winds, are expected to be in the teens for the entire area.

Much like its upper-level counter-part, the Clipper will override the
high by Wednesday mid-day. This will send a cold front through the
area some time Wednesday morning. There is very little moisture with
this FROPA, so precipitation looks unlikely. The timing and speed of
this cold front will have a large impact on high temperatures
Wednesday. The earlier it arrives, the cooler temperatures will be,
potentially maxing out in the 20s to low 30s. If the front is slow,
temperatures could easily warm into the upper 30s to mid 40s. The 1Z
NBM mean favors the slower arrival. However, GFS, ECMWF, and CMC-NH
guidance all show the 850 mb front moving through the CWA by 12Z
Wednesday, which would favor quicker FROPA timing. Behind this
front, winds look to be pretty strong. GFS and CMC-NH guidance show
the 850 mb LLJ speeding up to around 40-50 kts Wednesday morning.
With this occurring around 12Z, there should be a PBL inversion,
preventing these winds from mixing down to the surface. There is a
~20% chance this inversion does not prevent mixing and surface gusts
around 40+ kts would occur. Overnight temperatures will not be too
impacted, still cooling into the lower to mid teens; areas with
snowpack could drop into the upper single digits.

Thursday and Friday, although the upper-level features are in pretty
good agreement, the 850 mb level is not. The GFS is showing a
prolonged 30-40 kts 850 mb northwesterly LLJ continuing through
Friday morning. The ECMWF and CMC-NH are showing a much weaker LLJ,
around 10-25 kts, if that can even be considered a jet. With a
stronger jet, expect cooler temperatures Thursday and Friday, like
mid 20s to lower 30s Thursday and 30s Friday. With a weaker LLJ,
temperatures could warm into the 40s Thursday and mid 40s to mid 50s
Friday. GEFS guidance is somewhat in the middle of these options,
but slightly favors the GFS, giving slightly higher confidence
(55%/45% split) to the cooler temperatures occurring. With overnight
clear skies and fairly calm winds, expect low temperatures to remain
in the teens Thursday and Friday night.

Around the Friday-Sunday timeframe, another trough is expected to
move in from the Pacific Northwest. There is low confidence in what
this trough will bring, but expect cooler temperatures and a
slightly increased potential for precipitation.

---------------------------------------------------------------------
List of acronyms
NBM - National Blend of Models
GFS - Global Forecast System
GEFS - GFS Ensemble Forecast System
ECMWF - European Centre for Medium-range Weather Forecasts
CMC-NH - Canadian Meteorological Centre-Northern Hemisphere
FROPA - FROntal PAssage
PBL - Planetary Boundary Layer
LLJ - Low Level Jet
mb - Millibar
kts - Knots
Z - Zulu time (UTC)
CWA - County Warning Area
CONUS - CONtiguous United States

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 330 AM MST Sat Jan 18 2025

KGLD...sub VFR conditions will be possible from taf issuance
through about 15z with light snow possible. Northerly winds gust
up to 25kts. VFR conditions return after 16z. Northerly winds
continue to gust up to 30kts through 00z with northwest winds up
to 11kts from 01z through the rest of the taf period.

KMCK...sub VFR conditions are currently forecast through the
period. There is a possibility of sub VFR cigs moving over the
terminal from the northwest after about 09z. Northerly winds
gusting up to 25kts at taf issuance could reach 30kts through
the day. Tonight, northwest winds up to 11kts are anticipated.

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Extreme Cold Watch from this afternoon through Tuesday morning
     for KSZ001>004-013>016-027>029-041-042.
CO...Extreme Cold Watch from this afternoon through Tuesday morning
     for COZ090>092.
     Winter Weather Advisory until 2 PM MST this afternoon for
     COZ091-092.
NE...Extreme Cold Watch from this afternoon through Tuesday morning
     for NEZ079>081.

&&

$$

SHORT TERM...99
LONG TERM...CA
AVIATION...99