FXUS65 KPUB 111722

Area Forecast Discussion
National Weather Service Pueblo CO
1022 AM MST Mon Dec 11 2023

.SHORT TERM...(Today and tonight)
Issued at 341 AM MST Mon Dec 11 2023

Key messages:

- Still cool, but less wind. Passing mid to high level clouds.

- A few snow showers possible over the central mountains.

Detailed discussion:


A weak, positively tilted ridge ahead of some troughing to the
northwest of the region will be propagating overhead throughout the
day. This will keep northwesterly flow in the mid to upper levels
over the area. Due to a weak perturbation transitioning over
northern Colorado, there will be just enough instability with the
help of some orographic lifting to produce some light snow showers
over the central mountains, although these will be very light and
may only produce some light accumulations on the western facing
slopes of the northern Sawatch Range at best. Mid to high level
clouds will be passing over, and cooler a very weak cold frontal
boundary will move through later in the afternoon and help to
reinforce some cooler air. There will be less wind than yesterday
with no downsloping westerly wind component, so max temperatures
will remain on the cooler side, around the average for this time of
year or slightly below for most locations. Highs for the plains will
be generally in the mid to upper 50s for the eastern plains, and
upper 40s to low 50s along the I-25 corridor. For the higher
elevations, max temps will be in the low to mid 40s for the mountain
valleys, and 20s to 30s across the mountain tops.


Dry conditions can be expected across the CWA. Any snow shower or
two remaining over the central mountains should come to an end by
around midnight. Passing mid to high level clouds will help to keep
temperatures slightly modified, so temperatures will not quite as
cold, especially for the plains. There will be some cold air
drainage from the mountains into the San Luis Valley, so this will
likely be the coldest spot with temperatures near the 0F degree
mark. For the plains, lows will generally be in the low 20s, and the
rest of the higher terrain will likely fall into the teens for most
locations, with a few single digits for the highest mountain
valleys. -Stewey

.LONG TERM...(Tuesday through Sunday)
Issued at 341 AM MST Mon Dec 11 2023

- Beneficial precip expected for areas generally south of US50
during the midweek time frame

Main weather story for this forecast period is a broad closed low is
forecast to evolve over the southwestern CONUS and track across the
southern Rockies during the midweek time frame. This system promises
to bring a swath of precipitation to parts of the region, mainly
south of the US50 corridor. The probability of this occurring is
high (>80%), however the exact amounts of precip and how much of it
will be frozen still needs to be determined. Overall, this system is
relatively warm as it does not have much cold air with it. Although
there is a chance of snow with it over the plains, how much
meaningful accumulation will likely be low as dewpoints with it will
be around 30F and ambient temps wont be all that cold. The mountains
on the other hand (San Juans/southern Sangres region) will have a
better chance of a wet heavier snow, although accums may be low
given the potential wetness of the snow. As for timing, precip will
start to affect mainly the southern tier late Tuesday and last
through midday Thursday. The heaviest precip will likely occur
during the Wednesday evening time period, especially over the
greater Baca county region. Based of guidance from the DESI
platform, QPFs of about an inch are being indicated in the ensemble
guidance for the greater Baca county region (these same numbers are
being indicated in the WPC 7 day QPF)

As for the northern tier of the forecast region (central mtns and
PPR), confidence in receiving any meaningful accumulations of precip
(liquid or frozen) with this system is much lower, although not

Areas along the US-50 corridor will be along the gradient with this
system so probabilities of receiving precip is in the 50-70%
category with amounts in the 0.2 to 0.4 inch range.

I should note that the ensemble guidance is primarily showing either
rain, snow or a mix of the two. The data is NOT showing a strong
signal for freezing precip.

As for potential highlights, I can envision some winter weather
highlights being needed eventually for the San Juans and southern
Sangres, but the other areas confidence is very low that highlights
will be needed due to uncertainties of precip type and how much
melting will occur.

By late week, the system will move to the southeast and we will dry
out, and temperatures will warm into the 50s plains for the weekend.

Overall, the potential for beneficial precip for the southern part
of the forecast area appears high for the midweek time frame.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1022 AM MST Mon Dec 11 2023

KCOS, KPUB, and KALS: VFR conditions are expected over the next 24
hours. Winds will remain light and less than 10 knots through this
TAF period. Otherwise, dry conditions, with increasing mid to high
level clouds this evening into tomorrow morning, is expected for all
three TAF sites.