006
FXUS65 KBOU 091820
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1220 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 /18Z TAFS through 18Z Friday/...
Issued at 1055 AM MDT Thu Jul 9 2026

VFR conditions expected through the TAF period. Winds are
currently northeast at all terminals and should continue for the
afternoon. Scattered showers and thunderstorms will then develop
over the foothills in the next few hours and then trek east
throughout the afternoon. Have kept the TEMPO groups as is for all
TAF sites, with gusty VRB outflow winds of 35-40 kts possible.
Expect convection to end by 00Z, with outflow boundaries mainly
keeping winds from the east this evening. Tonight, a bit more
westerly wind is possible within the drainage flow.

For tomorrow, light northeasterly winds are expected again.
Despite a decrease in moisture, another round of isolated showers
are possible later in the afternoon. Have introduced a PROB30 for
this reason, with gusts of 25 kts.

&&

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

&&

$$

DISCUSSION...12
AVIATION...MAI

NWS BOU Office Area Forecast Discussion