Hoyt, Colorado Weather Forecast Discussion

828
FXUS65 KBOU 281807
AFDBOU
Area Forecast Discussion
National Weather Service Denver/Boulder CO
1207 PM MDT Sun Sep 28 2025
.KEY MESSAGES...
- Scattered afternoon/evening showers and thunderstorms return
  today, mainly over the mountains.
- Additional weak showers and storms possible Monday and Tuesday.
- Temperatures will remain above normal most days.
&&
.DISCUSSION /Through Saturday/...
Issued at 240 PM MDT Sat Sep 27 2025
It`s shaping up to be another mild and dry day across the forecast
area today, with temperatures running slightly cooler than yesterday
behind an early morning weak cold front. This morning`s upper-air
charts and satellite water vapor imagery clearly show a closed
upper-level low spinning over SoCal. This feature continues to
keep deeper moisture just to our south and west.
Aside from some increasing afternoon cloud cover, mainly over the
higher terrain, and a slight uptick in southeasterly surface
winds across the plains, it should be a great day to get outside
and catch your favorite Colorado college football team in action!
With limited cloud cover over the lower elevations, temperatures
will cool off fairly quickly after sunset tonight. Expect
overnight lows to dip into the mid to upper 40s and 50s across the
plains, and into the 30s for our mountain valleys.
Looking ahead, a transition in the synoptic pattern is expected on
Sunday, as the aforementioned upper-level low opens up and shifts
northeastward. This will allow subtropical moisture to spread
farther north and east, increasing the potential for scattered
showers and storms, primarily across the higher elevations, but
can`t rule out the possibility of an isolated one or two making
their way onto the lower elevations. Forecast guidance indicates
MLCAPE values between 200-800 J/kg by Sunday afternoon, which
would be sufficient to support isolated lightning and weak storms.
With these being high-based, we could see some gusty outflows,
however, no severe weather is anticipated. Afternoon highs are
expected to run a few degrees above normal, with low to mid 80s
expected across the plains, 60s and 70s for the foothills and
mountain valleys.
QG ascent will increase slightly on Monday as the shortwave moves
across the region. This still looks to be the day with a slightly
higher chance of any showers or storms holding together enough to
make it off the plains, with some guidance showing up to around
1000 J/kg of MLCAPE across the urban corridor in the afternoon.
Behind the shortwave, ensembles show mostly zonal flow aloft will be
in place for the middle of the week. A trough looks to enter the
Pacific Northwest late in the week that will start to bring
increasing southwesterly flow aloft into Colorado. There are still
some differences with timing and amplitude of the approaching
trough, but we should start to see some moisture return by the end
of the work week, and temperatures start to drop towards near normal
by the weekend.
&&
.AVIATION /18Z TAFS through 18Z Monday/...
Issued at 1138 AM MDT Sun Sep 28 2025
Uncertainties remain with today`s wind direction as the expected
cyclone/shear zone has developed just east of DIA this morning.
Winds have been bouncing back and forth between SSW and WNW,
through the morning, and are expected to transition towards a more
northerly component over the next few hours.
The main concerns for today will be with gusty outflows from
passing showers/weak storms. Hi-res guidance shows potential for
some showers or weak storms forming along the aforementioned
boundary along the Palmer Divide by 22/23Z before moving northward
towards the TAF sites. Scattered showers and storms are also
expected to develop over the higher terrain and move northward,
mainly staying anchored to the mountains where instability will be
greatest. With DCAPE values expected to reach between 800-1000
J/kg, could see microbursts/gusty outflows as showers pass over,
with gusts between 25 to 30 kts. While the probability of
lightning is low for the TAF sites (~10%), still can`t completely
rule it out.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Bonner
AVIATION...Bonner

NWS BOU Office Area Forecast Discussion