628
FXUS65 KBOU 121955
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
155 PM MDT Tue May 12 2026

.KEY MESSAGES...

- Summerlike warmth with dry weather this week, with highs in the
  80s for the lower elevations Wednesday through Sunday. A few
  highs in the 90s possible Wednesday across the urban corridor.

- A few afternoon showers possible today through Friday, mainly
  across the Front Range mountains and foothills. Wednesday will
  have the best coverage with a few late afternoon storms
  possible.

- Elevated fire weather conditions will develop across the far
  eastern plains of Colorado on Wednesday. Another round of
  elevated fire weather conditions possible for portions of the
  plains, especially the Cheyenne Ridge, and South Park on
  Thursday.

&&

.DISCUSSION /Through Tuesday/...
Issued at 148 PM MDT Tue May 12 2026

Today is quite the pleasant weather day with mostly sunny skies,
light winds, and temperatures in the low 70s across the plains.
Besides a weak shower or two with breezy winds across the higher
terrain, there are no weather concerns.

An upper level ridge will move just east of Colorado on Wednesday
as a trough moves into Idaho. The southwest flow aloft will create
the conditions for compressional warming in our forecast area
tomorrow due to subsidence. Denver has a 60% chance to reach 90
degrees tomorrow which would tie the record high set in 1915. The
main concern for tomorrow will be elevated fire weather conditions
across the eastern plains. Strengthening lee cyclogenesis will be
in place over northeast Colorado resulting in moderate southerly
winds (sustained 15-20 mph with gusts up to 35 mph) mainly along
and east of a line from Limon to Sterling. With south winds, there
will be weak moist air advection with dew points in the upper 30s
forecast across the eastern plains. This moisture will keep
minimum relative humidity values around 20 percent and above.
Therefore, critical fire weather conditions are not forecast but
elevated conditions will exist east of a line from Limon to
Sterling.

The shortwave trough will then pass well to the north of Colorado
on Thursday. A weak cold front will pass through Colorado Thursday
afternoon which will decrease humidity. Some gusts up to 30 mph
are possible in the northern foothills and across the plains by
the Cheyenne Ridge. This will lead to elevated to potentially
critical fire weather conditions in those areas. Elevated fire
weather conditions may exist in South Park and across the Palmer
Divide as well. Otherwise, it will be another warm day with
temperatures in the mid to upper 80s across the plains.

There will be pleasant weather conditions on Friday with above
normal temperatures and mostly sunny skies.

A trough will begin to develop over the western US on Saturday
and will approach Colorado late Sunday into Monday. Lee
cyclogenesis will develop across northeast Colorado on Saturday
with southeast winds across the plains. This may bring in enough
moisture for a few thunderstorms to develop across the eastern
plains during the evening. On Sunday, the cyclogenesis will
intensify and depending on where the center of the low pressure
system develops, there could be fire weather concerns. Sunday
night into Monday morning, a strong cold front will move across
our forecast area bringing a chance of rain to lower elevations
and snow the higher elevations.

&&

.AVIATION /18Z TAFS through 18Z Wednesday/...
Issued at 1128 AM MDT Tue May 12 2026

VFR conditions will prevail for all terminals through the TAF
period. Easterly flow persists this afternoon and is set to
continue through mid-evening. Scattered cumulus with bases near
120 will develop 21-22Z today, but a largely capped environment
with limited instability should prevent any outflow concerns for
the most part, although KAPA will be closer to any high-based
activity favoring the Palmer Divide.

This evening, winds are likely to turn to the SE for KDEN/KAPA as
a robust convergence zones sets up, with speeds 14-17 kts possible
through most of the overnight hours. Some uncertainty as to when
this boundary will wash out/push east, with a short window of more
typical S/SW drainage flow possible before lighter and more
variably winds fill in for the morning period.

There`s marginally better instability Wednesday along with
little/no capping, so introduced a PROB30 for KDEN for potential
outflow gusts beginning near 21Z.

&&

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

&&

$$

DISCUSSION...Danielson
AVIATION...BRQ

NWS BOU Office Area Forecast Discussion