296
FXUS65 KBOU 270016
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
616 PM MDT Wed Aug 26 2026

.KEY MESSAGES...

- Scattered afternoon/evening thunderstorms expected for theI-25
  Corridor and plains. A few storms could become severe, with
  large hail and strong winds possible.

- Thunderstorm coverage decreases Thursday and Friday with mainly
  isolated high-based showers/storms with gusty winds.

- Temperatures return to the 90s Friday andSaturday across the
  plains.

- Thunderstorm coverage increases for late Saturday and Sunday.

&&

.DISCUSSION /Through Wednesday/...
Issued at 1140 AM MDT Wed Aug 26 2026

An upper level high will be centered over Arizona/NewMexico
today with ridging extending northward all the way to Alberta.
This will lead to a northwest flow aloft over Colorado. Outflow
from thunderstorms last night and thismorning increased low level
moisture but also cooled the airmass. Temperatures are slow to
warm this morning, with 11 AM readings only in the mid to upper
70s. DEN ACARS soundings still show a strong inversion centered
around 700mb. Forecast model soundings show this as well, but they
don`t appear strong enough regarding the inversion. This leads to
a highly uncertain thunderstorm forecast and severe threat for
later today. MLCAPE is still forecasted to climb to 1000-2000 J/kg
along and east of the I-25 corridor. The 0-6km bulk shear reaches
30-40 knots. The 30 knots is borderline for severe storms, but
where we see east to southeast surface winds around 10 knots, the
bulk shear will be closer to 40 knots. This favors areas east of a
line from Fort Collins to DIA for severe storms. Because of the
slower heating, storm development will likely be delayed with late
afternoonand early evening hours being favored. Again, given the
strength of the inversion, the severe thunderstorm threat remains
highly uncertain.

The upper-level high will remain centered to our southeast, but
the ridge axis shifts eastwardover Colorado on Thursday. This
will bring warmer temperatures and some drying. Precipitable water
valuesfall below an inch throughout the area, except for the far
eastern plains. Warmer air aloft, less moisture and instability
will lead to a notable decrease in thunderstorm activity. There
should be enough lingering moisture for isolated high-based
showers and thunderstorms. Any rainfall is expected to be light,
with gusty outflow winds up to 45 mph possible. However, southeast
winds will prevail over far eastern Colorado, helping to preserve
low level moisture. MLCAPE will reach 1000-2000 J/kg with 0-6km
bulk shear of around 40 knots, which would favor severe
thunderstorms. Warmer air aloft may cap convection, though.
Convergence along a boundary is likely needed for storms to
initiallyform, and models generally don`t show this happening.

The high intensifies (slightly) and drifts northeastward for
Friday. Temperatures warm further, with highs expected to reach
the lower to mid 90s across northeast Colorado. Models hint at a
slight increase in moisture, which should fuel a round of
afternoon/evening showers and thunderstorms. Given the warm
temperatures and limited moisture and instability, the
showers/storms are expected to be high-based with gusty outflows
being common.

For the weekend, an upper level trough (eventually strengthening
into a closed low)will track east across the northwest part of
the country. This will push the upper level high east of the
region, with southwest flow aloft developing over Colorado. We`ll
see an increase in monsoon moisture leading to a better chance for
showers and thunderstorms. The very warm air hangs on for
Saturday with lower to mid 90s expected again, but temperatures
will cool to the mid 80s to lower 90s for Sunday.

The weather pattern for next week starts to look like a late
summer/early fall pattern, featuring stronger west to southwest
flow aloft with one or two shortwave troughs passing across the
region. For now, models show enough moisture each day for a round
of showers and thunderstorms. However, wouldn`t be surprised if we
end up with a dry and breezy day due to subsidence behind an
exiting shortwave trough.

&&

.AVIATION /00Z TAFS through 00Z Friday/...
Issued at 615 PM MDT Wed Aug 26 2026

Outside of brief thunderstorm impacts, VFR conditions are expected
to prevail through the TAF period. We`ve extended the TEMPO to 03Z,
as there is enough activity in the area currently to produce
outflows/microbursts well into the evening. Latest radar scans show
multiple outflows looking to move through KDEN`s vicinity within the
next couple hours, creating the potential for showers/storms to form
over the airport. Should anything form directly over the airfield,
gusty winds up to 40kts and heavy rain with visibility reductions to
1-2SM are the main concerns. Once convection moves out of the area,
winds should turn south/southwest overnight before becoming variable
in the early morning hours, around 14-16Z, and then turning
northeast for the afternoon. There`s a lot of uncertainty as far as
tomorrow`s storm chances go. While confidence is low (10-20%) in
true shower/storm coverage over the area, the potential for outflows
with gusty winds remains, and so we`ve elected to keep the PROB30 in
the TAF for now.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...BM
AVIATION...AGS

NWS BOU Office Area Forecast Discussion