819
FXUS65 KPUB 230521
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
1121 PM MDT Sun Sep 22 2024

.KEY MESSAGES...

- Slow clearing overnight, then low chance of some patchy frost
  over high mountain valleys early Monday morning,

- Much warmer Monday with isolated showers/thunderstorms over
  the higher terrain.

- Dry conditions throughout the rest of the week

- Returning to normal temperatures by the end of the week.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 232 PM MDT Sun Sep 22 2024

Currently, upper low easing into swrn Nebraska this afternoon, with
extensive wrap-around cloud shield covering much of southern
Colorado. Mid-level lapse rates are just steep enough under the cold
pool aloft to pop some very weak/isolated convection, though
most precip so far has been sprinkles at best. Clouds holding temps
down with readings mainly 40s/50s, a few 60s where clouds have
broken a bit on the plains and across the San Luis Valley. For the
remainder of the afternoon into early evening, still a risk of some
weak mountain convection, and will keep some very low pops in place
until around sunset, especially over the ern San Juans where
a few models hint at activity lingering into the evening.

Overnight, expect clouds to slowly clear, though a few models
(especially NAM), don`t show substantial clearing until early
Sunday morning as low is very slow to lift east. Given enough
uncertainty in clearing trends and also very wet ground/moist low
level air mass over the San Luis Valley, will hold off on any
frost/freeze highlight for now, as any near freezing temps look
brief and limited in coverage to areas along/near the Rio Grande.
Wet ground may lead to some patchy ground fog along the river
as well, especially if clearing happens early enough.

Monday, upper low pulls away with brisk nw flow aloft developing
across the state by late day. Still enough moisture/instability
for some weak mountain convection in the afternoon, though a good
portion of 22/12z models have trended drier with only very sparse
activity, and will adjust pops downward somewhat, especially away
from the mountains. Main story Monday will be the rapid return of
warm air, as mid level heights rise and 700 mb temps push back above
10c by afternoon. Expect most lower elevations to climb deep into
the 70s as a result, and maybe an 80f reading around Canon
City/Pueblo/La Junta where mixing is deepest.

&&

.LONG TERM /MONDAY THROUGH SUNDAY/...
Issued at 232 PM MDT Sun Sep 22 2024

Monday Night and Tuesday:

The lagging trough aloft will move out of the region shortly after
the beginning of the long term forecast period. There will be a few
lingering showers (rain and snow) over the Continental Divide, but
they will dissipate shortly after sunset. Slightly below average
minimum temperatures are expected Tuesday morning with values in the
40s over the plains and the mid-to-low 30s over the mountain
valleys.

Tuesday will be another below average temperature day for southern
Colorado with high temperatures reaching the low to mid 70s over the
plains and the 60s to 70s over the mountain valleys. Dry conditions
are expected across the region and some gust winds up to 25 to 30
MPH are expected over the far eastern plains.

Wednesday through Saturday:

For the rest of the week a upper level high pressure center develops
aloft over the intermountain west, a low propagates south over
Missouri, and a tropical system makes its way towards the southern
states. All of this has impacts on our weather in southern Colorado.
The closed low over Missouri is blocking movement from the high
pressure over Colorado and later in the week the tropical system
interacts with the closed low which will keep it stationary until it
fuses with the tropical system and travels east - which will likely
happen after the long term forecast period. All of this means that
there will be dry conditions over Colorado with temperatures right
around average for this time of year, gradually warming up as
through the end of the week. The closed low and the tropical system
are very dynamic systems, so models will have a hard time resolving
their exact movement, especially when they begin to interact with
each other - so we`ll keep an eye out on any impacts for southern
Colorado.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1118 PM MDT Sun Sep 22 2024

The main concern for this forecast will be fog potential,
especially for the San Luis Valley.

For KCOS, VFR expected next 24 hours with light winds.

For KPUB, VFR likely next 24 hours with light winds. The only
concern is there is an outside chance of some br around sunrise
tomorrow morning.

For KALS, they have received a lot of precip over the last 24
hours and this low level moisture is trapped in the valley. It
ha cleared out, and the probabilities have increased for fog,
possibly dense, to form in the valley floor. as of midnight,
KALS was clear per sat pi imgy and T/Td spreads were only 2F.
Will continue to monitor low clouds GOES products and adjust TAF
as needed.

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SHORT TERM...PETERSEN
LONG TERM...SKELLY
AVIATION...HODANISH