498
FXUS65 KBOU 040925
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
325 AM MDT Fri Sep 4 2026

.KEY MESSAGES...

- Warm and mainly dry conditions through Saturday, with isolated
  afternoon showers/storms favoring the high country.

- Increasing moisture Sunday/Monday with a rise in shower/storm
  coverage, including for the lower elevations.

- Warm temperatures favored to continue next week, with at least
  isolated to scattered showers and storms most afternoons.

&&

.DISCUSSION /Through Thursday/...
Issued at 223 AM MDT Fri Sep 4 2026

There haven`t been any notable changes to the forecast over the
last couple of days. I`m not sure if this pattern would
technically qualify as an omega block - with two closed lows off
the Pacific Northwest and New England, with a large ridge in
between - but either way most of Colorado will be "blocked" out of
any meaningful pattern change over the next week or so.

Dry southwesterly flow aloft remains in place this morning, per
water vapor satellite imagery. The ridge centered across the south
central CONUS is expected to gradually strengthen today and shift
a bit westward. We`ll start to see a bit of moisture creep into
the southern half of our CWA by this evening, which could lead to
isolated or widely scattered showers and a few thunderstorms late
this afternoon into the evening. Otherwise, temperatures should be
a couple degrees warmer than yesterday.

The flow aloft should turn to more of a S/SSW direction by this
weekend, allowing for better moisture advection into the region.
This should result in widely scattered but relatively weak
convection across most of the high country.

Continued moisture advection is likely for Sunday and Monday.
With an increase in boundary layer moisture, convection should be
more widespread but still limited in coverage given essentially no
large scale/synoptic support.

As mentioned in the past few forecast cycles, models begin to
diverge by early or mid-week next week. However, the overall
pattern would still favor a ridge off to our east with some sort
of cutoff low or open trough near the west coast. Moisture should
remain over our area - leading to continued chances of afternoon
showers or thunderstorms - but significant/widespread rainfall
still appears unlikely with no notable shortwaves or fronts moving
through.

&&

.AVIATION /06Z TAFS through 06Z Saturday/...
Issued at 1131 PM MDT Thu Sep 3 2026

VFR through the TAF period. Winds tonight have already turned to
drainage, and outside of a possible weak/brief push of WNW winds
overnight, little is expected through Friday AM.

Friday will likely feature another shear zone or Denver Cyclone
during the afternoon hours. Given a fairly similar setup I expect
winds to behave rather similar compared to Thursday, with
predominantly easterly wind at DEN/BJC and southeast at APA.
There`s a slightly higher chance for some weak convection during
the evening hours, and the PROB30s at APA/BJC were extended to
match the timing of DEN. Once any showers diminish Friday evening
there should be a quick return to drainage flow.

&&

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

&&

$$

DISCUSSION...Hiris
AVIATION...Hiris