734
FXUS65 KBOU 280541
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1141 PM MDT Thu Aug 27 2026

.KEY MESSAGES...

- Isolated/scattered high based showers/storms Friday with gusty
  winds.

- Temperatures return to the 90s Friday and Saturday across the
  plains.

- Thunderstorm coverage increases for late Saturday through Monday.

&&

.DISCUSSION /Through Thursday/...
Issued at 302 PM MDT Thu Aug 27 2026

The upper level high and ridge axis shifts over Colorado today,
bringing warmer temperatures and drier air. Precipitable water
values fall to near normal (0.6-0.9") across the area. MLCAPE
will be around 500 j/kg, so we should see some shower/thunderstorm
activity. However, mid level warming is expected to limit development
this afternoon and evening. With DCAPE values of 1000-1500 j/kg,
gusty outflow winds will be the main issue with gusty up to 50
mph. Can`t rule out a few isolated gusts near 60 mph. Brief moderate
to heavy rain will also accompany the thunderstorms. The showers/storms
end by mid evening as the airmass stabilizes. Thunderstorms tracking
south over western Nebraska could clip the far northeast corner
of Colorado later this evening/tonight. These storms will be in a
more moist and unstable airmass, with MLCAPE of 1000-2000 j/kg and
be severe if the pass over the area.

The upper level high that has been to our southwest will begin
shifting eastward Friday as an upper level trough moves onto the
Pacific Northwest coast. Temperatures continue to warm with highs
expected to reach the lower to mid 90s across northeast Colorado.
Some models show a subtle increase in moisture, others dont. If we
see this increase, it would just increase the number of high-
based showers and thunderstorms. Gusty outflow winds up to 50 mph
will again be the main threat. Southwest flow aloft will increase
Saturday throughout the day as the upper-level trough moves inland
and the upper-level high shifts southeast of the Central Rockies.
We will see one more day of very warm temperatures with highs in
the lower to mid 90s over northeast Colorado. Moisture increases,
mainly late in the day. This will lead to a better chance for
showers and thunderstorms.

On Sunday, southwest flow aloft will increase becoming somewhat
strong for this time of year as the upper level trough moves
across Montana. This will increase monsoon (mid/upper-level)
moisture. However, with a lack of a cold front or easterly push
low-level moisture will be limited. We still expect a round of
scattered afternoon/evening showers and thunderstorms. Temperatures
begin to cool, but remain slightly above normal. Much of the same
is expected for Monday, except that a shortwave trough embedded
in the southwest flow could bring a better chance for showers if
it tracks over the region.

For Tuesday through Thursday, southwest flow aloft will continue
with the upper level high remaining southeast of the region and
troughiness to our north. As for shower and thunderstorm chances,
they decrease as the airmass dries. There may be one or two days
with no convection, but it is too soon to tell when.

&&

.AVIATION /06Z TAFS through 06Z Saturday/...
Issued at 1137 PM MDT Thu Aug 27 2026

VFR conditions are expected through the TAF period. Drainage winds
are established at DEN/APA and should continue through the
overnight hours.

A little more uncertainty with both the prevailing winds and
convective potential for Friday. Statistical guidance follows a
typical diurnal pattern, with a gradual clockwise turn to the
winds during the morning hours before settling on a light
north/northeast by the early afternoon. Scattered high-based
showers will likely complicate this a bit, with inverted-V
soundings favoring gusty high-based convection during most of the
afternoon and evening. Have kept the PROB30 with only a few minor
adjustments at this point.

Once convection diminishes during the evening, we should see a
quick return to drainage flow for Friday night into Saturday.

&&

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

&&

$$

DISCUSSION...WFO Pueblo
AVIATION...Hiris

NWS BOU Office Area Forecast Discussion