366
FXUS65 KBOU 130516
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1116 PM MDT Thu Mar 12 2026

.KEY MESSAGES...

- Prolonged period of critical fire weather conditions through
  Saturday as successive high wind events and dry conditions
  impact our forecast area.

- Mountain snow expected to develop late Saturday following a cold
  front, with precipitation potential, strong north winds, and
  much cooler temperatures extending into the lower elevations
  through Sunday.

- Rapid warming begins Monday into Tuesday, potentially
  culminating in record-breaking temperatures mid to late next
  week.

&&

.DISCUSSION /Through Thursday/...
Issued at 140 PM MDT Thu Mar 12 2026

The strongest winds this afternoon in our area are generally near
the northern I-25 corridor between Fort Collins and the Wyoming
border and in the Foothills and higher elevations of the
mountains. Winds look to weaken and retreat back into the
mountains after sunset, with speeds remaining strong in the higher
foothills and mountains through the overnight period and into the
late morning tomorrow. These strong mountain winds will gradually
decrease starting in the early to mid afternoon, but remaining
breezy throughout Friday. Strong winds aloft will likely mix down
to the surface across much of the plains tomorrow, causing wind
gusts around 30 to 50 mph in the afternoon. A Red Flag Warning was
issued for the I-25 corridor and majority of the eastern plains
for tomorrow due to these gusty winds and dry conditions.

There is potential for another mountain wave event on Saturday, but
wind speeds look a bit lower than today`s event in the mountains and
Foothills (still in the 55 to 75 mph range). The mountain wave
potential for Saturday so far looks less pronounced, with this
event maybe being more of a brute force event rather than a
mountain wave event, leading to more widespread gusty winds on
the plains compared to today. Strong winds will move in aloft
ahead of an approaching trough. These winds are expected to mix
down to the surface in the afternoon, causing widespread gusts
around 35 to 60 mph. Right now, much of the plains are sitting at
a low to medium chance (10 to 40%) of reaching High Wind Warning
Criteria, but this is something we`ll need to keep an eye on.
These winds combined with the continued dry conditions will lead
to another day of critical fire weather conditions for much of the
plains.

We`re starting to get a bit more concerned about the wind potential
behind the front late Saturday into Sunday. The front is going to
be strong, with packed isotherms and isobars behind it. Models
are showing winds at 700mb around 40 to 70kts behind the front.
This event looks more like a bora, which tends to impact a much
larger portions of the plains than purely mountain wave events.
Mid level QG subsidence will be strong behind the front, allowing
those stronger winds aloft to push down to the surface, providing
the potential for strong wind gusts overnight through Sunday. Even
with this strong mid level QG subsidence, we`re still looking at
the potential for some precip during this time as well. The strong
northerly winds could trigger the formation of the Longmont
anticyclone, which provides better upslope at the surface for
areas to it`s south. This combined with our area being in the
left exit region of a strong upper level jet and frontogenesis
with the cold frontal passage, we will likely see mountain snow
and could see some snow across the plains (especially in areas
under banding and areas that see better upslope flow). With how
cold it is behind the front, the main precip type is expected to
be snow or rain transitioning to snow. The mountains, I- 25
corridor, and urban corridor have a high chance (>70%) of seeing
at least some snow accumulations on Sunday with lower chances for
the plains further east. Snow amounts are still relatively
uncertain (especially with the possibility of snow banding), but
right now the best chance for snow amounts of a couple of inches
or higher will be in the mountains, foothills, and areas just
south and west of the Denver metro (including the Palmer Divide).

Temperatures Sunday afternoon will be around 30 to 45 degrees
cooler compared to Saturday. Our current forecast keeps highs in
the low to upper 30s for Sunday, but there is a medium to high
chance (35 to 75%) that the plains east of the I-25 corridor could
stay below freezing all day. With these much colder temperatures
and strong winds, wind chills will bottom out in the single digits
to possibly even the negatives for early Sunday.

An upper level ridge will build into the area starting Monday.
Temperatures will warm quickly under the ridge, with highs reaching
into the 70s for much of the plains by Tuesday, with the potential
for record breaking high temperatures for the second half of the
week.

&&

.AVIATION /06Z TAFS through 06Z Saturday/...
Issued at 1112 PM MDT Thu Mar 12 2026

Winds have remained gusty at DIA and BJC, however, they should
gradaully decrease by 07z at DIA and turn more SSW.  BJC may
continue to see gusty winds thru 09z before switching to a more
south direction.  APA will switch to a more SSW diection by 07z.

On Fri, winds will become westerly by 16z and then more WNW by
19z.  Gusts from 30 to 35 mph will occur at times after 16z
thru the aftn. Winds will gradually decrease by early Fri
evening.

Finally, VFR conditions will be in place thru the period.

&&

.FIRE WEATHER...
Issued at 140 PM MDT Thu Mar 12 2026

A Red Flag Warning will remain in effect through the late evening.
Wind gusts will begin to weaken around 7 to 8PM today, with RHs
rising above critical thresholds around 8 or 9PM. Humidities will
be lower tomorrow with min RHs around 10% to 20% across the
plains. Winds are expected to be weaker tomorrow, but gusts will
still be around 35 to 50mph in the afternoon. The Fire Weather
Watch for tomorrow was upgraded to a Red Flag Warning due to the
critical conditons expected across much of the plains.

Fire weather concerns on Saturday will be critical to extremely
critical. Conditions will be just as dry if not drier on Saturday,
with min RHs around 10% to 20%, but winds will be stronger.
Expect strong west winds around 25 to 35 with gusts around 40 to
60mph in the plains. A Fire Weather Watch was issued for much of
the plains for Saturday afternoon. A strong front will move
through the area Saturday night, leaving strong north winds in
its wake. The front will also bring much cooler temperatures and a
chance for snow, which will help limit fire weather concerns for
Sunday. Temperatures will then warm back up, with very above
normal temperatures expected by mid week.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 7 PM Saturday to 8 AM MDT Sunday
for COZ031-033-034.

High Wind Warning until noon MDT Friday for COZ033>036.

Red Flag Warning from 11 AM to 8 PM MDT Friday for COZ238>251.

Red Flag Warning from 11 AM to 9 PM MDT Saturday for COZ238>251.

&&

$$

DISCUSSION...AP
AVIATION...RPK
FIRE WEATHER...AP

NWS BOU Office Area Forecast Discussion