899
FXUS65 KBOU 092358
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
558 PM MDT Thu Jul 9 2026

.KEY MESSAGES...

- Scattered to numerous thunderstorms through early evening, with
  a few severe storms possible over the northeast plains.

- Prolonged period of very to hot temperatures arrive Saturday,
  lasting through most of next week.

&&

.DISCUSSION /Through Thursday/...
Issued at 1209 PM MDT Thu Jul 9 2026

Airmass has dried slightly over the past 24 hours with
precipitable water ~0.60 (in). This is about a tenth inch
decrease from yesterday at this time on the Denver ACARS
sounding. Water vapor satellite imagery also shows this drier
air.One can also pick out a shortwave trough centered roughly
over southwest Wyoming. We`ll see a slight increase in moisture
and lift this afternoon as this wave advances eastward. MLCAPE has
trended lower as well with 400-1000J/kg expected this afternoon
across northeast Colorado. The far northeast plains may end up
more unstable, up to 1500J/kg. Gusty outflow winds up to 70, brief
heavy rain, and small hail are expected to be the main threats
today with the highest threat over the far northeast plains.

The upper level ridge off to the southwest begins to build
northward Friday, causing flow aloft to turn northwesterly.
Precipitable water values will be similar to today`s, with
slightly less instability. Most of the storms Friday are expected
to form over the higher terrain and the Palmer Divide due to a
lack of large scale lift tomorrow afternoon. The number of storms
is expected to decrease because of this. Northwest flow aloft will
push the storms southeastward, potentially leaving the far
northeast plains free of storms.

The ridge intensifies and will be centered over Utah and Colorado
on Saturday. Mid level temperatures will warm, and the airmass
will dry. Can`t rule out a stray shower/weak storm over the Palmer
Divide and Front Range Mountains/Foothills, but chances are low
(less than 20%). Elsewhere, dry conditions will prevail. Surface
temperatures warm as well, with highs reaching the 90s across
northeast Colorado.

For Sunday and next week, the ridge continues to intensify as it
tracks northeastward. The 500mb heights are expected to top 600
(DAM) which is impressive, especially since the high will park
itself over Wyoming and South Dakota. East to southeast flow
around the high will help hold in some low level moisture over
eastern Colorado. This low level moisture and the weak upslope
easterly winds will likely keep areas along the Front Range and
across the eastern plains from breaking records. As for areas west
of the Continental Divide, this easterly flow will be a downslope
component and help dry the airmass, For Summit and Grand
Counties, record highs will be likely and all time records could
be reached. Chances for showers and thunderstorms Sunday through
Thursday are very low over the higher terrain, and almost nil
across the Front Range and eastern plains.

&&

.AVIATION /00Z TAFS through 00Z Saturday/...
Issued at 549 PM MDT Thu Jul 9 2026

VFR conditions expected through the TAF period. Dying showers over
the foothills produced an outflow boundary with strong northwest
winds that moved through all terminals. The northwest wind is
expected to last until around 01Z as the winds will become light
and then turn to southeast. Light and variable winds are expected
overnight.

Towards sunrise, there may be enough moisture advection towards
BJC and DEN that fog or low clouds could develop. The chance for
fog or low clouds is around 10% so it was not enough to include in
the TAFs. However, if it were to form, visibility could drop to 2
SM with ceilings around 500 feet.

Drier air aloft will suppress shower and storm activity tomorrow.
However, showers and storms over the foothills may still produce
gusty outflow winds that could bring 25 knot gusts to all
terminals. BJC and APA have a better chance (30-40%) to see these
outflow winds than DEN (~20% chance).

&&

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

&&

$$

DISCUSSION...12
AVIATION...Danielson

NWS BOU Office Area Forecast Discussion