356
FXUS65 KBOU 301109
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
509 AM MDT Thu Jul 30 2026

.KEY MESSAGES...

- Isolated showers and thunderstorms this afternoon, with a few
  strong-to-severe storms possible, mainly for the eastern plains.

- Another round of isolated thunderstorms possible Friday
  afternoon.

- Heat returns by the weekend, with temperatures possibly reaching
  up to 100 F on Sunday and Monday.


&&

.DISCUSSION /Through Wednesday/...
Issued at 225 AM MDT Thu Jul 30 2026

Current radar shows ongoing isolated rain showers along the high
terrain, with a few of them spilling onto the plains. These showers
do have the ability to produce gusty outflow winds, as surface
observations have already reported gusts up to 50 mph in the
foothills (40 mph around the Boulder area). With the passing of a
weak upper level shortwave, additional showers and thunderstorms are
possible before sunrise, mainly for the northern mountains, with
gusty outflow winds as the main concern.

With northwest flow aloft today, our source for monsoon moisture
will be cut off. However, isolated showers and thunderstorms are
still expected this afternoon. CAMs favor storms forming over the
foothills and I-25 corridor and trekking east through the afternoon,
where they will tap into better moisture, and thus better
instability. Most storms are expected to be marginal, but can`t rule
out isolated severe thunderstorms producing 60 mph winds and hail,
especially for the eastern plains where SPC has introduced a
Marginal Risk (1/5). In addition, with PWs still over an inch, heavy
rainfall is possible with strongest storms. However, flash flooding
is not much of a concern, given faster storm motions. Overnight
Thursday, a weak backdoor front will bring `cooler` temperatures for
Friday, with forecasted highs expected to be in the 80s to low 90s.

The shortwave embedded in the upper level ridge will bring another
round of isolated showers and thunderstorms on Friday. Modeled Skew-
T soundings show more favorable shear profiles, but instability
seems to be lacking. Denver metro and areas south have been included
in a Marginal Risk (1/5) for severe weather, with hail and strong
outflow winds as the main concern.

Guidance is in good agreement of the upper level ridge
restrengthening once again over the weekend, with above normal
temperatures returning to the region. Ensemble solutions continue to
indicate highs reaching up to 100 both Sunday and Monday for the
plains. After that, models begin diverging as multiple upper level
shortwaves arrive next week. Depending on the evolution of these
disturbances, we could be seeing `cooler` temperatures by Tuesday
(unfortunately it would be short lived), with precipitation
chances returning by midweek. However, it is too soon to go into
the details yet as things could still change.

&&

.AVIATION /12Z TAFS through 12Z Friday/...
Issued at 503 AM MDT Thu Jul 30 2026

VFR conditions expected through the TAF period. Drainage flow
currently at DEN and APA will soon give way to lighter westerly
winds in the next hour or so. Observations over the eastern plains
show patchy areas of fog. However, with drainage flow in place,
confidence is high that fog would not reach the terminals. If DEN
were to get easterly winds in the next hour, then would become
more concerned.

Another round of afternoon convection is possible this afternoon,
however there is still some uncertainty wit exact coverage of
storms. For this reason, have kept PROB30 as is, with gusty
outflow winds of 30kts as the main concern. Models still show
weak frontal passage between 04Z-06Z overnight, with drainage
flow returning slightly later than normal.

&&

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

&&

$$

DISCUSSION...MAI
AVIATION...MAI

NWS BOU Office Area Forecast Discussion