555
FXUS65 KBOU 111856
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1256 PM MDT Mon May 11 2026

.KEY MESSAGES...

- Summerlike warmth and drier weather this week, with highs in the
  80s for the lower elevations.

- Warmest temperatures of the week (mid to upper 80s for the
  plains) on Wednesday and Thursday.

- A few afternoon showers and an isolated thunderstorm possible
  from Tuesday through Friday, mainly across the Front Range
  mountains and foothills.

&&

.DISCUSSION /Through Monday/...
Issued at 1213 PM MDT Mon May 11 2026

The well-advertised ridge across the southwestern CONUS is
gradually strengthening, leaving most of Colorado in a warm but
relatively quiet pattern over the next several days.

We`re well on track to seeing highs in the mid/upper 80s across
the plains today, with 12 PM temperatures already in the low 80s
at most locations. With dry air overhead (shown well by water
vapor satellite), only a few clouds are expected through afternoon
and evening hours.

A weak cold front is still expected to arrive sometime late
tonight or early on Tuesday. The front is expected to bring some
short-lived cooling (highs ~5-10F cooler than today), along with a
modest increase in moisture. Most guidance develops a narrow
corridor of instability across the Front Range during the
afternoon hours, and the weak upslope flow behind the front should
allow for a couple of weak showers and perhaps a brief
thunderstorm despite some capping.

Temperatures should quickly warm back up into mid/upper 80s by
Wednesday, with those well above normal temperatures continuing
into the weekend. Guidance has been slowing warming temperatures
on Wednesday, with ~30% of ECMWF ensemble members now getting DEN
to its first 90F high of the year. However, statistical guidance
remains a few degrees cooler and our current forecast is still
just under 90F for most locations. There is also a weak wave
working through the region Wednesday afternoon, with deeper
moisture aloft and better instability across most of the forecast
area. If we`re going to see any convection/measurable
precipitation this week, Wednesday afternoon would be the time to
do it.

Drier zonal flow by Thursday slowly transitions to southwesterly
flow aloft by the upcoming weekend. Guidance is generally in
better agreement handling the few 500mb shortwaves across western
North America in this time period, and generally keeps things
quite dry through the rest of the forecast period. The pattern
does look like it would turn a little more active by early next
week with a couple stronger shortwaves noted in today`s guidance.

&&

.AVIATION /18Z TAFS through 18Z Tuesday/...
Issued at 1140 AM MDT Mon May 11 2026

VFR conditions will last through the forecast period. Latest
observations near KAPA and KDEN show light and vrb winds. We
expect this to continue through at least early this afternoon
before eventually becoming NE to E around 21 to 22z. Winds at KBJC
are also light currently (under 8 knots), but generally in an
easterly direction. KBJC will likely have at least a few hour
period of NW winds of 10-15 kts this afternoon/early evening
after 22z. These NW winds are not expected to reach KDEN or KAPA
at this time. Drainage winds are forecast ahead of the incoming
cold front. Winds should stay under 12 knots through at least 10z.

The cold front will move through all three sites between 10z and
11z early tomorrow morning turning winds to be nearly due north,
first moving through KBJC and KDEN before KAPA. A few lower
clouds around 9000 to 10000 ft AGL are possible early tomorrow
after the cold frontal passage, but VFR conditions should
continue. Winds will be at most between 15 and 20 kts immediately
following the cold front, but will then be under 10kts after 15z.
By tomorrow afternoon, winds will turn to NE/E once again with
only a some sct mid- to high- level clouds.

&&

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

&&

$$

DISCUSSION...Hiris
AVIATION...MV

NWS BOU Office Area Forecast Discussion