717
FXUS65 KBOU 251842
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1242 PM MDT Tue Aug 25 2026

.KEY MESSAGES...

- Scattered afternoon and evening showers and storms through at
  least Thursday. A few storms could become severe, particularly
  on Wednesday.

- Slightly cooler with near normal temperatures today and
  Wednesday.

- Gradual drying and hotter temperatures by Friday and the
  weekend, but a few storms still possible especially on Sunday.

&&

.DISCUSSION /Through Tuesday/...
Issued at 1236 PM MDT Tue Aug 25 2026

Satellite imagery shows cumulus clouds forming in the high country
and radar shows the first showers of the day starting over the last
hour or so in the high country. West to northwest flow aloft will
continue for the next few days around the periphery of the high
pressure currently situated over New Mexico. At the surface, upslope
flow is expected for each of the next two afternoons. As we saw
yesterday, this has brought the return of scattered rain chances to
the area. Notably, temperatures are expected to "cool" into the
upper 80s with the increase in cloud cover each afternoon. Have
slightly nudged down high temperatures this afternoon for the Urban
Corridor given the cloud cover sticking around and temperatures
still in the low 70s at the present time. According to ACARS
soundings, a cap remains in place as of 12pm given the limited
heating this morning.

Showers and thunderstorms will continue to form in the high country
early this afternoon before sliding into the I-25 Corridor by mid
afternoon, initially favoring areas near the Palmer Divide and
Cheyenne Ridge. The storms will then spread into the eastern plains
by the late afternoon. DCAPE this afternoon will be around 1200-1400
J/kg, which could translate to 40 to 50 mph wind gusts near any
storm/outflow boundaries. These storms should gradually strengthen
as they move into a more favorable environment in our eastern
plains. 0-6 km bulk shear could briefly reach 30 kts and MLCAPE will
approach 1000 J/kg in the far eastern plains. Strong winds and large
hail are the main threats with these storms mainly east of a line
from Sterling to Akron to Limon as storms start to cluster. We can`t
rule out a marginally severe storm between the I-25 corridor and the
aforementioned locations this afternoon. With fast storm motion (~20
kts) and only scattered storms today, only concerned with very
isolated pockets of flooding.

Overnight tonight, outflow from storms to our east should move
through and increase the low-level moisture for the eastern Plains.
This could introduce a stratus deck tomorrow morning for the Urban
Corridor and adjacent plains and potentially limit the overall
severe potential. A weak disturbance is expected to slide through
overhead for Northeast CO tomorrow afternoon and slightly increase
storm coverage as well as increase the flow aloft. Frankly, there is
currently a wide spread in solutions for tomorrow afternoon`s
environment for the Urban Corridor. Given the uncertainty, have
slightly nudged down PoPs for the Urban Corridor to ~40%. Confidence
increases as you move further east that a more favorable environment
for severe storms will be in place. Nevertheless, MLCAPE could reach
as high as 1500 to 2000 J/kg and 0-6 km bulk shear will be ~30-40
kts for much of the plains for tomorrow afternoon. There is a slight
(2/5) risk in place from the Storm Prediction Center for tomorrow
afternoon for the I-25 corridor and adjacent plains. Strong winds
and large hail of at least 1.5 inches in diameter will be the main
threats. Storm timing will be similar to today with storms clearing
our eastern plains counties by 8pm to 10pm. Although PWATs should be
around 150-175% of normal, with fast storm motion (~25 kts) once
again, am only concerned with isolated flooding for tomorrow at this
time.

By Thursday, the high pressure is forecast to expand near the Four
Corners, lowering rain chances. By Friday, rain chances are expected
to be nearly shut off (except for an isolated chance in the high
country). Subsequently the mid-level thermal ridge will strengthen
and lead to highs in the mid-90s for the plains on Friday and
Saturday. For Sunday and Monday, a shortwave trough is expected to
move through the far northern US- along the Canada/US border- and
shunt the high pressure off to the south and east. This should
reintroduce more cloud cover and rain chances for the area,
especially by Monday, with high temperatures lowering once again
into the mid to upper 80s for the plains.

&&

.AVIATION /18Z TAFS through 18Z Wednesday/...
Issued at 1214 PM MDT Tue Aug 25 2026

Winds are light (

NWS BOU Office Area Forecast Discussion