756
FXUS65 KPUB 220954
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
354 AM MDT Sun Sep 22 2024

.KEY MESSAGES...

- A cloudy and cool 1st day of Astronomical Fall with showers
  over and near the higher terrain.

- Crisp overnight lows with potential for frost across the high
  mountain valleys.

- Showers and thunderstorms are expected over and near the
  higher terrain on Monday and Tuesday, with diminishing chances
  for precipitation from Wednesday onwards.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 349 AM MDT Sun Sep 22 2024

Current water vapor imagery and upper air analysis has an upper
circulation southeast of Grand Junction, pivoting across south
central Colorado at this time, with regional radars indicating
associated precipitation lifting out across the southeast mountains
and plains. Current observations indicating snow levels hovering
around 10,000 feet this morning, with CDOT and other webcams indicating
some accumulations on the grass across Monarch and Fremont Passes,
as well as the summit of Pikes Peak.

Latest models indicate the upper low opening up as it continues to
pivot across the plains, leaving a baggy upper trough to translate
across the region through the afternoon and into the High Plains by
tonight. Movement of this system will keep moisture within modest
mid level easterly upslope in place through the late morning, before
moisture slowly scours out as mid level flow turns more north to
northwest through the afternoon and into the evening. This will keep
showers ongoing over and near the higher terrain of the eastern
mountains through the morning, with the potential for showers and
few thunderstorms over all of the higher terrain this afternoon and
into the early evening, as the baggy trough continues to exit the
Rockies. Precipitation to remain generally light, with any additional
snow accumulations of an inch or two above 10,000 feet. However, will
keep current winter weather advisory in in place through the morning
for the higher peaks of the Central Mtns and into the Pikes Peak region.

With clouds across the region through much of the day, will see little
movement in temperatures, with highs mainly in the 50s across the lower
elevations, and generally in the 30s and 40s across the higher terrain,
save for the 20s at the peaks. Perfect timing for the 1st day of Fall
with the autumnal equinox occuring at 644 AM MDT! Clouds clear through
the late afternoon and evening, with cool over night lows in the 30s
and 40s area wide, leading to the potential for some patchy frost,
mainly across the high mountain valleys.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 349 AM MDT Sun Sep 22 2024

Monday..

After a chilly start, we warm up quickly throughout Monday as
shortwave energy embedded in north-northwesterly flow aloft
traverses the area. This wave looks to bring ample moisture and
instability, enough to spark isolated to scattered showers and
thunderstorms over and near the higher terrain on Monday afternoon.
Storms are not expected to be severe on Monday, with main risks
being gusty outflow winds and lightning. Daytime highs on Monday
will be around 15 degrees warmer than Sunday, but still a few
degrees shy of normal for this time of year. This will mean expected
highs in low to mid 70s across our plains, with a few upper 70s
possible across the Lower Arkansas River Valley, 60s and low 70s for
mountain valleys, and 50s for higher terrain locations. Light snow
above 11,000 ft will be possible, though accumulations are not
expected Monday. High res model guidance continues to show good
agreement with a cold frontal boundary pushing through sometime late
Monday night and into Tuesday morning. This front will keep rain and
weak thunderstorm chances in our forecast through Monday night and
into Tuesday morning as well.

Tuesday..

Models bring an end to showers and storms over our plains through
Tuesday morning, but tend to keep easterly upslope favored wind
components in place throughout the day across our plains. This trend
suggests that we might have lingering chances for cloud cover,
cooler temperatures, and possibly even light precipitation for our
eastern mountains and mountain adjacent plains on Tuesday. Showers
and storms are expected to redevelop over our southern mountains on
Tuesday as well. Daytime highs on Tuesday are looking to be at least
a few degrees cooler than Monday, but could end up being several
degrees cooler depending on the extent of our upslope.

Wednesday Onwards..

Models diverge markedly through the second half of our work
week and into the weekend. The GFS develops the ridge over the
middle of the country, with high pressure centered over us for a
majority of the period. The EC and the Canadian push this
weekend`s low down into southern Texas and close it off, where
it sits until later this weekend sometime. Ensembles do not show
much confidence in precipitation for our region with either
solution, though there could be very noticeable differences in
expected temperatures. Stayed with the NBM for this package as
it seems to be a good middle ground. Overall, near to just above
normal temperatures look more likely with the GFS solution, and
near to just below normal temperatures appear likely with the
EC and Canadian solutions.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 349 AM MDT Sun Sep 22 2024

Upper low across south central Colorado will pivot into northeastern
Colorado through the late morning, leading to baggy trough translating
across the Rockies through the afternoon. Movement of this system will
keep moisture within mid level easterly flow in place through the morning,
with flow aloft slowly becoming more north to northwest this afternoon.
This in turn will keep showers ongoing over and near the higher terrain,
with MVFR and IFR cigs in place at COS, PUB and ALS through the late
morning as surface winds become more east to southeast. Cigs gradually
improve into the afternoon with COS likely the last to improve to VFR
conditions after 18Z. VFR conditions persist through the rest of the
taf period, with generally light diurnal wind regimes at the terminals
overnight.

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until noon MDT today for COZ058-060-
082.

&&

$$

SHORT TERM...MW
LONG TERM...EHR
AVIATION...MW