725
FXUS65 KBOU 120605
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1205 AM MDT Thu Mar 12 2026

.KEY MESSAGES...

- Prolonged period of critical fire weather conditions Thursday
  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 and much cooler temperatures
  extending into the lower elevations through Sunday.

&&

.DISCUSSION /Through Wednesday/...
Issued at 211 PM MDT Wed Mar 11 2026

Temperatures are cooler today behind yesterdays front, with much
of the plains in the mid to upper 40s early this afternoon. We do
have some decent winds aloft across the northeast portion of the
state, which are mixing down this afternoon, creating gusts
around 25 to 45 mph. Winds will weaken with the loss of daytime
heating this evening.

Winds and fire weather concerns will increase for Thursday. The
pressure gradient will tighten significantly as a strong surface
low moves to our northeast and a surface high builds on the
windward side of the Rockies. Models are showing winds at ridgetop
around 60 to 75kts. The direction of the winds is a little more
northwest than we would like to see for mountain wave development,
but it`s still in the necessary range (models are a bit closer to
300 or 310 degrees, where we would typically prefer closer to 280
degrees). We could see some weak subsidence from the right exit
of the upper jet and weak or potentially reverse shear at
mountains top, which will both help mountain wave development. The
main question when it comes to ingredients is whether the stable
layer will develop and if it develops whether it will be in the
correct location for mountain wave amplification. To put it
plainly, confidence is high that it will be very windy at
elevations above 7000ft. Confidence decreases as we go to lower
elevations, with low to medium confidence in high winds reaching
down to 5000ft. If we can get a strong mountain wave to develop,
confidence will increase in the stronger winds progressing east
off the Foothills and into the plains. Right now, we`re thinking
wind gusts around 70 to 90 mph at the higher elevations and
northern Foothills and gusts around 50 to 70 in the nearby
adjacent plains and southern Foothills.

The northern plains along the WY/CO border could also see some
strong winds on Thursday, as a 700mb jet sets up over the area.
Decent mixing will bring higher winds down to the surface and the
strong NW winds will bring winds ripping off of the Cheyenne
Ridge. The plains along the border could see wind gusts around
65mph at times. Channels of stronger winds are also expected to
come off of the mountains and into the plains tomorrow afternoon.
The exact locations of these stronger wind channels is very hard
to predict, but areas in the plains and urban corridor could see
occasional gusts around 50mph.

A weak backdoor front will push into northeast Colorado overnight
Thursday into Friday. It will provide a brief wind shift and
could keep temperatures slightly cooler in our NE plains Friday,
but other than that impacts will be limited. The pressure gradient
and upper level winds will weaken for Friday, but it will still
remain breezy. Winds in the higher elevations of the mountains
will remain in High Wind Warning Criteria through the late morning
Friday, with wind gusts in the plains around 20 to 40mph in the
afternoon.

We`re looking at the potential for another mountain wave high wind
event for Saturday. Models are showing cross barrier flow around
60kts with widespread 700mb winds around 30 to 50kts across the
area. Right now, winds in the mountains and Foothills look a bit
weaker with this event compared to Thursday`s, while winds in the
plains look to be more widespread around 40mph. An upper level
trough is forecast to approach the area late Saturday into Sunday.
Ahead of this upper trough, we`ll see a surface low develop near
the area, which is forecast to drag a strong cold front through
starting late Saturday. We could see strong winds behind this
front as well, with it turning into more of a bora-ish event.
There will be a chance for precipitation along and behind this
front, primarily overnight Saturday into mid Sunday. Precip
amounts for this event are still bouncing around between model
runs, but the majority of models do bring at least some light snow
into portions of the plains for Sunday, with a few inches in the
mountains. Temperatures on Sunday will be much cooler, with models
ranging anywhere from highs in the low 20s to highs in the upper
40s.

A warming trend will start on Monday as an upper level ridge
starts to build over the area.

&&

.AVIATION /06Z TAFS through 06Z Friday/...
Issued at 1205 AM MDT Thu Mar 12 2026

Main concern will be winds, as it is far more complicated today.
As a strong mountain wave develops, gusty westerly winds will
slowly emerge across the Denver metro. Like many events, this
looks to first develop as a few channels of stronger W/WNW flow,
with weaker easterlies elsewhere. Most guidance first mixes down
some stronger winds by around 16-18z, with more widespread gusts
to 30-38 kts by 20-22Z. KBJC will be more prone to stronger west
winds, with a few gusts of 38-45 kts expected, while at this time
the strongest winds (gusts >50 kts) are expected to hold in the
foothills. Winds should slowly decrease closer to 00z Friday,
though a few of those channels of winds could continue til ~06Z.
We`ll handle these variations, or at least potential variations,
with TEMPO groups for what we would think would be the less
persistent of the wind observations. Also note LLWS will be
possible anytime those surface winds are VRB or light easterly.

A more normal southerly winds flow is expected to develop at KDEN
and KAPA by 06Z Friday. KBJC may still see a few puffs of
stronger west winds after that time, although a weakening
mountain wave means they, too, will likely transition to more of
a S/SE flow.

VFR conditions will persist with only SCT-BKN high clouds.

&&

.FIRE WEATHER...
Issued at 211 PM MDT Wed Mar 11 2026

There will be borderline RFW criteria this afternoon for areas
around Weld and Morgan counties. RHs will hover around 15 to 20%
in this area, with gusts around 20 to 45mph. RHs will start to
increase and gusts will decrease around sunset. A Red Flag Warning
will be in effect for all of the I-25 corridor and eastern plains
tomorrow. Winds will be much stronger tomorrow, with lower RHs.
The strongest winds will be in the mountains and foothills
tomorrow, with strong west winds extending into the adjacent
plains and northern plains along the Wyoming/Colorado border. RHs
are expected to remain above critical thresholds in the Foothills
and higher elevations, with borderline critical RHs in the
adjacent plains and along the Wyoming and Colorado border. So, the
highest winds should be co-located with the more borderline RHs.
However, with how strong the winds will be, areas with RHs closer
to the 15% to 20% range will still see very concerning fire
weather conditions. Channels of stronger wind gusts around 50mph
could come off of the mountains in the afternoon into the I-25 and
urban corridors. Sustained winds should be closer to the 15 to 35
mph range in the areas not covered by the High Wind Warning, but
there could be gusts approaching 50mph as those stronger fingers
move into the plains. RHs in the urban and I-70 corridors will be
around 12 to 15%. Winds should start to weaken in the plains
around sunset, but will remain breezy for the northern plains and
foothills through much of the overnight period.

Winds will be weaker on Friday compared to Saturday, but they will
remain breezy especially in the I-25 corridor and portions of the
northeast plains. RHs Friday afternoon will drop into the 11% to
20% range. Once again, the strongest winds should stay in the
areas with the more borderline RHs, but a few areas (specifically
zone 239) will likely need an RFW at some point Friday afternoon.
RHs drop for Saturday, with some of our southern counties
approaching the single digits. Wind gusts will be around 25 to
45mph for much of the plains, leading to another day of critical
fire weather concerns. A strong front will move through Saturday
into Sunday, bringing much cooler temperatures and higher humidity
for Sunday.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
High Wind Warning from 4 AM Thursday to noon MDT Friday for
COZ033>035.

High Wind Warning from 10 AM Thursday to noon MDT Friday for
COZ036.

High Wind Warning from 10 AM to 7 PM MDT Thursday for COZ038-042-
048.

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

Fire Weather Watch Friday morning through Friday evening for
COZ238>249.

&&

$$

DISCUSSION...AP
AVIATION...20
FIRE WEATHER...AP

NWS BOU Office Area Forecast Discussion