193
FXUS65 KBOU 192359
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
559 PM MDT Fri Jun 19 2026

.KEY MESSAGES...

- Isolated showers and thunderstorms possible near the southern
  foothills, Park County, and Palmer Divide today.

- Elevated fire weather conditions in the mountains and valleys
  today with critical conditions expected on Saturday.

- Strong to severe storms possible across the eastern plains on
  Saturday and Sunday.

- Scattered coverage of showers and storms on Sunday, Monday, and
  most of next week across the plains.

&&

.DISCUSSION /Through Friday/...
Issued at 131 PM MDT Fri Jun 19 2026

A cold front dropped south across eastern Colorado early this
morning bringing northerly winds and a slight increase
inmoisture. Denver ACARS soundings show precipitable water around
a half inch with a strong inversion. Expect this to limit
precipitation chances to Park County and the Palmer Divide where
those locations will have the best chance at breaking the cap.
Temperatures are currentlyin the 70s across northeast Colorado
and should top out in the lower to mid 80s. A surge of east-
northeast winds is expected this evening, originatingfrom the
thunderstorms currently over Nebraska. This will increase low
level moisture tonight and lead to low clouds late tonight and
Saturday morning across parts of northeast Colorado.

Warmer temperatures are expected Saturday with highs reaching the
mid 80s to lower 90s. This combined with the increased low level
moisture will lead to an unstable airmass over the eastern plains
with MLCAPE reaching 2000-3000 J/kg. Southwest flow aloft over the
easterlylow level will produce good shear as well. Bulk shear
(0-6km) reaches 40-50 knots, enough for supercell thunderstorms to
form. Very large hail, damaging winds, and isolated tornadoes
will be possible. The main threat for the strongest storms is
expected to be east of the urban corridor. Dry air will be just to
the west, over the mountains and foothills and the moist unstable
layer is expected to be shallow across the urban corridor. This
could change if the easterly push is stronger and deeper than
expected. The main threat window looks to be 3PM to 7PM. After
this, the strongest storms are expected to move east of the area.

For Sunday, we`ll see a shortwave trough pass north of Colorado
during the day. A cold front associated with this will drop south
across eastern Colorado during the afternoon hours. The best
chance for thunderstorms will be over the eastern plains where the
best moisture and instability will reside. A few of the storms
over the plains could be severe again as MLCAPE reaches 2000 J/kg.
Over the mountains and mountain valleys, dry westerly winds will
prevail. Highs are expected to reach the mid 80s to lower 90s
across northeast Colorado with the coolest temperatures over the
northeast corner.

For next week, an upper level high over the US/Mexico border will
intensify while westerly flow aloft continues over the Central
Rockies. The set up next week will be similar to this weekend with
dry air over the higher terrain and easterly low level flow over
the plains transporting moisture into the state. Each
afternoon/evening should bring a round of showers and
thunderstorms. The uncertainty being how far west the moisture and
thunderstorm development will be. Highs are expected to be in the
80s most days with Tuesday possibly being the coolest with highs
in the 70s.

&&

.AVIATION /00Z TAFS through 00Z Sunday/...
Issued at 555 PM MDT Fri Jun 19 2026

VFR conditions are expected through at least about 06z tonight.
MVFR to IFR conditions are possible tomorrow morning due to
stratus. Winds are currently NE to E at all three TAF sites with
only sporadic gusts over 12 kts.

This is overall a messy and somewhat uncertain forecast as we
progress further out in time. A front/outflow boundary from
storms to our east is on track to move through KDEN around 03z to
04z bringing some gusty NE winds and increased low-level moisture.
This front could briefly reach KAPA and KBJC before sloshing back
to the east as a convergence zone.

Winds will turn to the north at KDEN and KBJC as the
aforementioned convergence zone moves to the east around 08z to
10z. A Denver cyclone is now likely to develop between 10z and 14z
with numerous models (HRRR, NAM Nest, NAM MOS, RDPS, RAP13) now
supporting this scenario. The cyclone is expected to shift north
throughout the early morning leading to light N to NW winds and
likely bringing some stratus to the three sites. We have kept the
lowered ceilings at all three sites as a result from about 10z to
as late as 17z. There is still a small, but decreasing chance
that the low clouds do not make it into the three sites.

A pseudo-front/boundary with N/NE winds to north of it and SW
winds to the south of it should set up somewhere just south of
KAPA tomorrow by late morning and afternoon. Models notoriously
mix out and bring NW winds to the sites faster than what usually
occurs, so have kept near N to NNE winds throughout the afternoon.
As the boundary moves to the north and east tomorrow afternoon,
showers and thunderstorms could fire off starting as early as 19z
with the highest chances currently expected just to the east of
KDEN. Have now included a mention of VCTS for KAPA and KDEN for
tomorrow afternoon with gusty winds possible from any outflows.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 11 AM to 9 PM MDT Saturday for COZ211>214-
217-218.

&&

$$

DISCUSSION...12
AVIATION...MV

NWS BOU Office Area Forecast Discussion