797
FXUS65 KBOU 232355
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
555 PM MDT Mon Mar 23 2026

.KEY MESSAGES...

- Record heat expected for Tuesday and Wednesday across much of
  the forecast area.

- Elevated to critical fire weather concerns by mid-week as a
  result of the exceptionally warm and dry conditions.

- Briefly cooler again to end the week, but well above normal
  temperatures again for the weekend.

&&

.DISCUSSION /Through Monday/...
Issued at 1244 PM MDT Mon Mar 23 2026

Zonal flow aloft continues today, but an increase in mid/upper
moisture has led to a few light snow showers across the higher
mountains. Based on CDOT webcams, it looks like snow has only
really managed to develop near a few of the higher mountain
passes, and this precipitation has been very light. Guidance
pushes in a slightly deeper patch of moisture later this evening
into the early overnight, and I suppose it`s possible (~10%
chance) a few higher mountains see an inch or two of snow
overnight... though most of the mountains will not see any
meaningful precipitation. Across the plains, temperatures are
slowly warming into the 60s and should peak in the low to mid 70s
across most of the urban corridor.

A robust upper level ridge will strengthen over AZ/NM by Tuesday
and Wednesday, leading to another period of record heat across the
forecast area. This feature has been remarkably consistent over
the past several cycles, with 500mb height standardized anomalies
>2.5 sigma. The core of the thermal ridge looks to set up almost
directly over our forecast area, with 700mb temperatures pushing
towards +12 to 15C by Wednesday afternoon (standardized anomalies
of 2.5-4 sigma). Unsurprisingly, that signal translates well
across all of the deterministic/ensemble and statistical guidance.
Temperatures on Tuesday should warm into the upper 70s to low 80s,
and a combined 77/80 of the GFS/ECMWF ensemble member forecasts
would break the daily record high for DEN (76F, 1896). While cloud
cover may limit the overall heating potential, low 80s look likely
for most of the urban corridor and plains.

Additional warming is expected on Wednesday. Given mid-level
temperatures similar to Saturday, upper 80s appear to be pretty
likely across most of the I-25 corridor and plains. A few of the
all-time March records set a few days ago could be challenged, if
MOS guidance is on the right track. Elevated to critical fire
weather conditions are also likely during the afternoon, given the
warm/dry conditions. While we did consider a Fire Weather Watch,
there is too much uncertainty with wind/wind gust potential here.
Cross sections and BUFKIT soundings suggest that boundary layer
maximum winds will only reach about 20-25kt... and as a lee trough
develops over the I-25 corridor in the afternoon, it will be
difficult to efficiently/consistently mix down the stronger winds
aloft.

Thursday remains a bit more of a question mark as a weak
shortwave races across our area, while a surface cold front sinks
southward into the region. Guidance has remained inconsistent with
the timing of the front, though it looks like we`re starting to
see a gradual shift towards a slower front. On the other hand, the
post frontal airmass looks to be trending a bit more
moist/cooler, with some models now attempting to spit out a
couple inches of snow across the higher foothills Thursday night
or Friday. That idea is broadly supported by the last couple
cycles of the ECMWF ensemble, though a couple tenths of QPF on Day
4-5 is not much to write home about.

Behind the cold front, cooler temperatures are likely to prevail
on Friday, and high temperatures are currently forecast to be near
or a little below normal. However, warmer weather is back in the
forecast again by the weekend with a ridge building back into the
region.

&&

.AVIATION /00Z TAFS through 00Z Wednesday/...
Issued at 537 PM MDT Mon Mar 23 2026

VFR conditions expected throughout the TAF period. A boundary will
move through DEN and APA shortly increasing southeasterly winds
this evening. Gusts could reach 20 knots for a short time. Winds
will then trend to drainage with normal speeds tonight. Light and
variable winds are expected tomorrow morning. By the afternoon,
northwest winds will develop at all terminals. Speeds will
generally be between 8-12 knots although some higher gusts could
occur.


&&

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

&&

$$

DISCUSSION...Hiris
AVIATION...Danielson

NWS BOU Office Area Forecast Discussion