377
FXUS65 KBOU 252357
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
557 PM MDT Sat Apr 25 2026

.KEY MESSAGES...

- Cooler, more moist weather pattern expected for much of the next
  week. Primarily light precipitation amounts, with the exception
  of some heavier rain under thunderstorms.

&&

.DISCUSSION /Through Saturday/...
Issued at 159 PM MDT Sat Apr 25 2026

Temperatures this afternoon are 10 to 30 degrees cooler compared
to this time yesterday. This combined with dewpoints around 10 to
20 degrees higher than yesterday has increased RHs enough to end
our string of critical fire weather days. Weak upslope flow will
be present this afternoon as surface winds turn more easterly over
the plains and winds stay out of the west/southwest in the
mountains. This will lead to isolated to scattered showers this
afternoon. However, precip chances and amounts will stay on the
lower end this afternoon due to the lack of a strong forcing and
moisture.

Precipitation chances on Sunday look more promising. Southerly
surface winds will bring in moisture at the surface, while
southwesterly mid level winds will bring in moisture from the
Pacific. This will bring PWATs to around 150% to 200% of normal by
Sunday afternoon. Aloft, a shortwave is expected to move over the
area, providing upper level lift. Models are showing a surface
low forming near our area in the afternoon as well, which will
provide surface convergence and act as a focal point for
convective development. Instability looks decent enough (SBCAPEs
~300 to 800) for a few thunderstorms in the afternoon, potentially
even an isolated strong to severe storm. Main hazards will be
strong winds, dangerous lightning, and small hail. Rain amounts
tomorrow will generally be in the trace to around 0.5 inch range,
however localized areas under thunderstorms could see higher
amounts. The best chance for higher rain amounts will be in our
northeast Colorado plains. In the mountains, snow is likely for
areas above 8,500ft, with most areas seeing around 1 to 6 inches.
Roads could be slick at times in the mountains Sunday afternoon
into Sunday night.

Another cold front is expected to move through the area early
Monday. Behind the front, we`ll see breezy N/NW winds, with gusts
around 30 to 45mph. As we go into the afternoon, winds will start to
turn more to the northeast in the plains adjacent to the foothills,
providing some decent upslope. This could be enough to trigger a few
showers and storms over the Foothills, which would then progress
east into the late afternoon and evening. However, QG subsidence
behind the departing shortwave may try and hinder precip
development.

Another shortwave is expected to move over the area sometime late
Monday through mid Tuesday. The lift associated with this
disturbance will provide low to medium chances for additional
showers during this time period. Periods of isolated showers will
be possible for mid next week as we remain in this unsettled
pattern. However, models do not have good agreement on the extent
and timing of said precip. The best chances for precip across our
area will be Sunday and Monday into Tuesday with decreasing
confidence as we go later into the week. The upper level system on
Thursday into Friday continues to progress southward and a bit
slower. This gives us a glancing blow from the low, giving us some
hope for additional precip, but overall chances look much better
to our south.

&&

.AVIATION /00Z TAFS through 00Z Monday/...
Issued at 557 PM MDT Sat Apr 25 2026

Forecast is on track with only minor changes. We see a few high
based showers/virga developing in/near the mountains and attempting
to spread onto the adjacent plains. We don`t see much in the way
of lower ceilings and IMC concerns until stratus deck over the
eastern plains spreads back westward. That most likely arrives
04Z-07Z and then gradually lowers overnight with continued
easterly flow and Denver cyclone in place. That cyclone does bring
some concerns for wind direction. KBJC is already on the back
side of cyclone with northerly winds and those will stay through
the entire TAF period. KAPA will likely transition from E-NE to NW
05Z-08Z, while KDEN will likely stay more E-NE until cyclone
passes nearby and potentially overhead with VRB winds as early as
10Z-12Z Sunday. There is more certainty that winds go NW even at
KDEN after 18Z-20Z Sunday, on the backside of the cyclone.

There is still relatively high confidence (70-80% chance) that
ceilings will lower to around 1000-1400 ft AGL at all airports
07Z-16Z, and have some cigs below 1000 feet for a few hours
10Z-14Z. Then expect stratus to break 16Z-17Z, although give or
take an hour or two like today.

Scattered to numerous showers and isolated thunderstorms are still
expected to develop after 19Z Sunday. We think the coverage of
TSRA is limited (MLCAPE only 200-400 J/kg) and the probability
would be limited to about 30%. But at this time, went with the
VCTS for about 3 hours during the most likely time (20Z-23Z) with
TEMPO -SHRA and G25kts with passing showers (DCAPE only about
300-500 J/kg). Best chance of showers will likely pass to the east
by ~23Z, with only isolated showers behind initial convection. It
will be difficult for lower ceilings to develop in the wake of
convection with some downslope just off the deck after the first
batch of showers.

&&

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

&&

$$

DISCUSSION...AP
AVIATION...20

NWS BOU Office Area Forecast Discussion