Area Forecast Discussion
Issued by NWS Pueblo, CO

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000
FXUS65 KPUB 220552
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
1152 PM MDT Sat May 21 2022

.UPDATE...
Issued at 1144 PM MDT Sat May 21 2022

Expanded and extended Winter Weather Advisories until 6 AM for
mainly Chaffee and Fremont counties. Models show an additional 1-2
inches on the whole, but local accumulations up to 4 inches could
occur under heavier snow bands through the overnight hours. Web
cam over MYP show snow packed roads and pavement temperatures are
around 32 degrees across much of the upper Arkansas River valley
across central and western Fremont and Chaffee counties. Given
probability of impacts to travel as roads becoming slushy or snow
covered, and the late season timing of this event, have opted to
extend and expand advisories. Will let advisories elsewhere come
down at midnight.  -KT


UPDATE Issued at 813 PM MDT Sat May 21 2022

Have downgraded winter storm warnings to advisories for the
remainder of this evening for the southeast mountains and adjacent
lower elevations. Satellite loops show some minor enhancement out
west as weak perturbation/jet steak in westerly flow aloft
translates across the region this evening. This should cause
another band of enhanced snowfall to develop across the Wets and
Wet mountain valley. Radar loops have been showing a gradual
increase in echo coverage but intensities have been lack luster so
far. However high res models suggest some enhancement is expected
within the next hour or two. Given the lighter snowfall rates have
downgraded to winter weather advisories through midnight.

Snow will shift northward into the Upper Arkansas River valley of
Chaffee and Lake counties after midnight to bring an additional
inch or two inches of snowfall for that area. For now, snowfall
rates do not look intense enough for additional highlights, but
will continue to monitor this closely as 00z model runs continue
to filter in. -KT

UPDATE Issued at 556 PM MDT Sat May 21 2022

Have extended highlights until midnight for the southeast
mountains, downgrading Teller county to an advisory through
midnight. Snow bands are expected to continue through the evening
with even some lingering snow continuing across the upper Arkansas
River valley after midnight though at decreased snowfall rates.
Have also added Huerfano county to a Freeze Warning for tonight as
temperatures are forecast to drop below 32 for a widespread enough
area. There will be a ribbon of freezing to near freezing
temperatures for western portions of the Pueblo county zone and
the western Las Animas county zone but for now it does not appear
this will occur over a sufficient area to warrant inclusion in the
warning. -KT

&&

.SHORT TERM...(This evening through Sunday)
Issued at 350 PM MDT Sat May 21 2022

Key Messages:

1)Snowfall will dissipate tonight, with a second quick shot over
Northern I-25 and westwards.

2)Freeze Warning tonight over El Paso County, with near-freezing
temperatures throughout the night.

3)Warmer on Sunday with the potential for lingering showers over the
mountains, and a new snowband near the Upper Arkansas towards Sunday
night.

Currently...

Some lingering snow bands are still present over Fremont and
Huerfano Counties. Snowfall rates are variable and observations in
those areas are scarce, but it appears that the heaviest snow is
behind us. Snow reports have been coming in steadily all day, with
highest amounts over the highest elevations of 18 inches or more.
Snow has been steadily waning throughout the afternoon, and will
continue to do so into this evening.

Today-Tomorrow...

Snow over the plains and southeast mountains will wane this evening,
with thick cloud cover sticking around. Temperatures across the
plains are expected to be cold, hovering just around or below
freezing from dusk until dawn. Given the snowpack on the ground in
El Paso County coupled with the cold temperatures, have issued a
Freeze Warning for the overnight hours. Main impacts will be damage
to tender vegetation and exposed irrigation systems. Most of the
snow over the plains will fizzle out shortly after midnight, and
later in the night into the very early morning hours, snow is
expected to redevelop over the Upper Arkansas River Valley into
Fremont, Teller, and El Paso Counties. For Sunday, an additional
daytime snowfall will largely depend on any upslope of increased
orographic flow we manage to get. As the axis of the upper-level
wave moves through overhead during the day tomorrow, the extra lift
and breezy west winds aloft could very well be enough to spark a
secondary round of narrow snow bands along northern I-25 near the
end of the day on Sunday and into the very beginning of the long-
term forecast period. Looking at additional total snow accumulations
through Monday morning, the lower elevations close to the higher
terrain will likely only see an additional inch or two, while the
higher peaks of the mountains could be seeing an additional 5-8
inches. The lower elevations could see slightly more on Sunday, if
snow bands do in fact manage to set up and persist for an extended
time. Temperatures on Sunday may serve to mitigate any additional
snowfall totals however, with 50s-60s expected across the area.

.LONG TERM...(Sunday night through Saturday)
Issued at 350 PM MDT Sat May 21 2022

Key Messages:

1) Banded precipitation over Pikes Peak Region on Sunday night into
Monday - snow above 10kft.

2) Low end chance at a severe storm over Baca County on Monday
afternoon and evening.

3) Low end flash flood risk over the Junkins and Spring burn scar on
Monday afternoon and Tuesday afternoon. Snow levels may negate the
risk, but the instability is there to create thunderstorms.

4) Critical fire weather conditions possible on Friday afternoon
across the mountain valleys and the plains.

Sunday night into Monday:

Another round of banded precipitation is expected on Sunday night
lasting through the overnight. At the surface, a lee cyclone is
expected to develop in response to an upper level system propagating
overhead. There will be an enhanced upslope flow regime over with
upper level providing synoptic support at there will be streams of
PVA and jet support. The main impacts will be snow over the
mountains and rain showers over the lower elevations with snow
levels around 9 to 10kft. The band should last through the overnight
into early Monday morning.

An interesting severe set-up is possible over the extreme
southeastern plains on Monday afternoon. The apex of a theta-e
tongue slips into Baca County on Monday morning, enhancing CAPE
values and enhancing the horizontal vorticity. Lapse rates, per
usual, are near dry adiabatic. Currently instability is below 1000
J/kg since models are not resolving much low level moisture reaching
quite reaching Colorado. This is something to monitor as 0-6km bulk
shear values are around 50kts. If conditions line up right, there is
a chance for a supercell with large hail, strong winds, and a very
low chance at an isolated tornado.

There is a flash flood concern primarily over the Spring and Junkins
burn scars on Monday afternoon. A weak front pushes some moisture up
the eastern slopes in conjunction with CAPE values around 600 J/kg.
This would be a low-end event, however if a storm develops locally
heavy rains are possible. The other thing that may negate this whole
paragraph is that the snow levels are around 10kft. Another thing to
monitor!

Tuesday:

Models begin to deviate on Tuesday on outcomes. The NAM provides a
more progressive system, whereas the GFS, GEFS, ECMWF, and EPS have
slower upper low that pushes a cold front over the CAPE rich
southern Sangre de Cristo Mountains and Wet Mountains. Which leads
to another possible flash flood possibility over the Spring and
Junkins burns scars. Once again, snow levels are at around 10kft,
which could negate this concern. Something we`ll have to monitor.
The NAMs guidance pushes storms off of the mountains and across the
plains, with CAPE values around 1,000 J/kg. There is higher
confidence in the former outcome, however, as the NAM is the outlier.

In the same vane, the GFS and ECMWF spin up a strong cyclone across
the Southern Plains of the US, tracking northeasterly over far
eastern Colorado. There are spatial issues as the ECWMF is further
east and the GFS is further west, but some wrap around moisture as
the low is intensifying may clip the CO and Kansas border. CAPEs are
limited, so a more stratiform event would be the outcome.

Wednesday and Thursday:

Upper level ridging develops over the region. Northwesterly flow
will remain in place on Wednesday, keeping our temperatures cool but
our conditions dry. Thursday the ridge axis propagates overhead,
bringing southern Colorado back to the 80s over the mountain valleys
and plains while remain dry once again.

Friday and Saturday:

Critical fire weather conditions are possible on Friday with the an
encroaching upper level system. The main area of concern will be the
mountain valleys and the plains Temperatures remain hot on Friday
and Saturday with the compressional heating off of the mountains,
though a cold front may cool things down on Saturday, which is still
uncertain.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1110 PM MDT Sat May 21 2022

KALS...overall, VFR conditions are expected through the next 24
hours at the terminal. A band of snow showers should remain to the
north across northern portions of the San Luis Valley. If snow
showers push south to near the terminals, reduced CIGS and VIS are
likely. Otherwise, CIGS should remain at or above 5 kft. Gusty
southerly winds are expected on Sunday afternoon.

KCOS...light snow will likely stretch across the terminal
overnight impacting CIGS and VIS. MVFR to IFR conditions are
possible with any snow that moves across the terminal. Conditions
should improve late tonight into Sunday morning. A few models do
have periods of snow continuing through the day on Sunday and
picking up again during the evening.

KPUB...periods of light snow may be possible through the overnight
hours, with much of the snow remaining to the west of the
terminal. If snow can move across the terminal, reduced CIGS and
VIS may be possible. Model guidance keeps snow Sunday afternoon
and evening north of the terminal.  Mozley


&&

.PUB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until midnight MDT tonight for COZ074-
075-079>083-087.

Winter Weather Advisory until 6 AM MDT Sunday for COZ072-073-
076>078.

Winter Weather Advisory until 6 AM MDT Sunday for COZ060>063.

Freeze Warning until 8 AM MDT Sunday for COZ084-085-087.

&&

$$

UPDATE...KT
SHORT TERM...GARBEROGLIO
LONG TERM...SKELLY
AVIATION...MOZLEY


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