272
FXUS65 KBOU 281855
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1255 PM MDT Tue Apr 28 2026

.KEY MESSAGES...

- Scattered showers/isolated weak thunderstorms rest of today, and
  then again Wednesday.

- More active pattern continues through the week with highest
  chance of more significant/beneficial precipitation in/near the
  Front Range Thursday - Thursday night.

- Warmer and drier conditions expected by the weekend.

- Chance of showers returns early next week.

&&

.DISCUSSION /Through Tuesday/...
Issued at 1255 PM MDT Tue Apr 28 2026

We`ve settled into the cooler and unsettled weather pattern over
the last few days, but most of the lower elevations have only see
light rainfall amounts so far (minus the 0.5" amounts over the
Palmer Divide last evening). Mountains have done fairly well with
several inches of snow and some much needed water for this year`s
record low snowpack. From the looks of it, we`ll stay in the
generally unsettled weather through Thursday night or Friday, with
the best chance of widespread beneficial precipitation Thursday
through Thursday night. However, there remain some uncertainties.

Through this evening, convective and generally weak showers will
gradually decrease with the loss of daytime heating as we`ve now
settled into weak subsidence behind this morning`s shortwave.
Thus, expect some clearing overnight with patchy fog development
on the eastern plains. Mountain areas should see most showers end
as well with only weak orographics and some drying. Temperatures
will be rather chilly overnight, with lows generally in the 30s
across the plains and some patchy frost.

The drying tonight will be short-lived as we start to see weak QG
lift and F-gen return for Wednesday. We will also have some
lingering low/mid level moisture which means additional convective
showers and a few thunderstorms due to diurnal heating and
destabilization. MLCAPE is only expected to reach 200-400 J/kg, so
wouldn`t expect more than mostly isolated weak thunderstorm
coverage. Temperatures will moderate slightly from today, but
still be nearly 5 degrees below normal.

While the forecast for Thursday - Thursday night is still looking
wet (and white for the mountains and foothills), there are some
uncertainties. An elongated trough with several embedded
disturbances is expected to drop southeast across the Central
Rockies and Great Basin during this period. There remains strong
agreement that the strongest wave and best lift will stay well to
our south in New Mexico, but we`ll still have persistent weak lift
and shallow/weak upslope to work with across out forecast area.
Lapse rates are advertised to be nearly moist adiabatic, so any
sort of forcing from the above two mechanisms should work
efficiently to produce precipitation. That said, we`re in the
midst of a drought, and as we`ve seen over the last week we`ve
largely underperformed with regard to precipitation output. At
least we have all favorable ingredients in place for a change
Thursday - Thursday night, although the upslope component is
questionable given the stronger portion of the trough is staying
well to our south. So, if we can get that upslope then we should
be able to capitalize on the ensemble precipitation output. Those
amounts suggest 0.3 to 0.7 inches for the I-25 Corridor, with
amounts closer to 1.0 inch across the Palmer Divide and in the
foothills south of Boulder. However, it should be noted the
ensembles still show a fair amount of spread (0.10-1+ inch along
the I-25 Corridor), likely dependent on the amount of upslope so
we`ll keep a close eye on that. Also, the chances of precipitation
greater than 0.25-0.50 inch drop off rather quickly to the
northeast across the plains (less upslope forcing), and also on
the leeward (west) side of the Front Range Mountains.

Temperatures will be cold enough for mostly snow above 7,000 feet,
with snow levels potentially dipping to around 6,000 feet at
times. A few of the coldest members would bring a couple wet
flakes as low as Denver but no accumulation is anticipated below
6,500 feet. We will likely need some winter highlights (Advisory)
for the Thursday - Thursday night/Friday AM period with potential
for slushy/snow covered roads for the foothills/eastern slope of
the Front Range, but a bit too early for that now.

Drier and warmer weather is shaping up for the weekend as an
upper level ridge builds over the region. After many days of below
normal temperatures, we`ll likely (70% chance) return to above
normal readings.

While we`ll generally stay under a ridge or col through early
next week, models are persistent in returning shower chances by
early next week. The increased shower chances appear to be a
result of weak surges pushing south across the plains and moisture
pooling along the Front Range.

&&

.AVIATION /18Z TAFS through 18Z Wednesday/...
Issued at 1144 AM MDT Tue Apr 28 2026

StratoCu have filled back in late this morning across the Denver
TAF sites with CIG sitting as low as BKN012-BKN022. Radar imagery
shows showers are present along the Continental Divide and latest
CAMs continue to show these moving eastward onto the lower
elevations in the next few hours. Winds generally have a
northerly component but should start to see some WNW winds develop
as showers move off the mountains by 21Z, mainly for KBJC and KDEN
where gusts between 15-25 kts will be possible through the
afternoon.

CIG should gradually improve/lift by the early evening behind the
showers. Could see some northeasterly to easterly gusts on the
backside of the passing showers before winds are expected to turn
to the SE and weaken by around 5-6Z at KDEN/KAPA, with winds
expected to turn to the NW to WNW at KBJC and weaken for the
overnight hours.

Tomorrow looks similar to today with a Denver Cyclone to bring
northerly winds back to the TAF sites by late morning/early
afternoon, with more showers or even some thunderstorms possible
by early afternoon and increasing chances for the evening.

&&

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

&&

$$

DISCUSSION...20
AVIATION...9

NWS BOU Office Area Forecast Discussion