National Weather Service Forecast Discussion

Thornton Weather Forecast   
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938
FXUS65 KBOU 252052
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
152 PM MST Wed Feb 25 2026

.KEY MESSAGES...

- Mountain snow will continue through tonight. The heaviest snow
  amounts will be in the Park and Medicine Bow Ranges.

- Elevated to critical fire weather conditions through Friday.

- Cooler temperatures and another wave of mountain snow possible
  for the weekend.

&&

.DISCUSSION /Through Wednesday/...
Issued at 152 PM MST Wed Feb 25 2026

Webcams and radar indicate snow has decreased across the
mountains. There looks to be an increase snow later this afternoon
and evening as lift from the jet moves over. In addition to this,
surface based CAPE up to 200 J/kg may result in stronger snow
showers as well. To the north over southern Wyoming and Nebraska,
showers and a couple thunderstorms have formed behind a weak cold
front and under the left exit region of the jet. Wind gusts to
around 55 mph will be possible on the leading edge of this
activity. After it pushes through weaker northerly winds are
expected. The chance for showers spreads south into northeast
Colorado for the late afternoon and evening hours.

Strong upper level ridge over the southwest quarter of the country
will bring warm and dry conditions through at least Saturday. Given
the warm and dry conditions, critical fire weather conditions are
expected where winds can gusts to 25 mph or higher. Wind forecast is
considerably uncertain with some models (HRRR) showing windy
conditions, especially Thursday morning. Other models, (GFS and
ECMWF), show much less wind. See the Fire Weather Section below for
details for Thursday and Friday Fire Weather details.

The ridge flattens slightly this weekend, but very warm temperatures
are expected to continue. One thing to keep an eye on is a cold
front slowly pushing southwest across the Central Plains. It likely
enters northeast Colorado sometime Saturday and pushes southwest to
the foothills Saturday night. This will lead to a slight cool down
for Sunday.

For next week Monday through Wednesday, a closed low moves into the
southwest part of the country Monday causing flow aloft to back to
the west to southwest. This low then progress eastward Tuesday and
Wednesday. Models struggle with the timing and track of closed
systems this far out. Would expect a cooling trend with a chance for
rain and mountain snow for early next week. A couple items that
appear likely with this system. One, this system doesn`t tap into
colder air from the north, so any precipitation across the plains is
expected to be rain. Two, moisture looks to be limited with this
system as it tracks across the intermountain west. Once it reaches
or passes east of the Rockies, it taps into moisture from the south.

&&

.AVIATION /18Z TAFS through 18Z Thursday/...
Issued at 1042 AM MST Wed Feb 25 2026

Models is good agreement with strong west-nothwesterly winds
expected at DIA into early evening.  Will go with a TEMPO group
for wind gusts to 45KTS as per some model guidance. Winds
decrease significantly early this evening. Will go with a mix of
normal drainage and weak downsloping overnight. Gusty
northwesterlies are expected again at DIA late Thursday morning but
speeds will not be as strong as today. There will be no ceiling
issues.

&&

.FIRE WEATHER...
Issued at 152 PM MST Wed Feb 25 2026

Fire weather concerns stay with us through Friday. Red Flag
Warning continues until 6PM today across all of the plains. It has
been very windy today with widespread gusts of 40 to 50 mph with
a few locations reaching 60 mph. Fortunately, an increase in
moisture is keeping relative humidities above 20 percent and in
some locations above 30 percent.

Confidence in the wind forecast over the next couple days is low.
On Thursday, the HRRR shows a well mixed airmass with gusty winds
to 40 mph by late morning and into the early afternoon before
weaker winds spread from north to south during the mid to late
afternoon hours. The HRRR has a history of over mixing the winds
and believe this is the case and favor the GFS and ECMWF
solutions. Those two models show the stronger winds (25-30 mph
gusts) late morning and then weaker north winds during the
afternoon. As far as moisture goes, relative humidity is expected
to bottom out at 13-18 percent, just reaching criteria in places.
Because of the wind uncertainty, and borderline relative
humidities, will leave the Fire Weather Watch in effect. Best
chance for a future upgrade will be across far northern Colorado.
For Friday we are looking at warm temperatures and drier
conditions with relative humidities 8 to 14 percent across the
lower elevations. Wind strength remains highly uncertain. At this
time, northern Colorado could see gusts up to 35 mph while farther
south, gusts to 25 mph will be possible.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until midnight MST tonight for COZ031-033.

Winter Weather Advisory until midnight MST tonight for COZ034.

Red Flag Warning until 6 PM MST this evening for COZ238>251.

Fire Weather Watch from Thursday morning through Thursday
afternoon for COZ238>240-242>246-248>251.

&&

$$

DISCUSSION...12
AVIATION...RJK
FIRE WEATHER...12

NWS BOU Office Area Forecast Discussion