133
FXUS65 KBOU 261135
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
535 AM MDT Thu Mar 26 2026

.KEY MESSAGES...

- Another unseasonably warm day Thursday with locally critical
  fire weather conditions in South Park, but cooling quickly with
  gusty northeast winds behind a mid afternoon cold front.

- Light to moderate rain/snow showers expected late Thursday
  evening through Friday morning.

- Temperatures warm well above normal again for the weekend into
  early next week.

- Signs of a pattern change by the mid to latter portions of next
  week, but highest chances of meaningful precipitation confined
  to the mountains.

&&

.UPDATE...
Issued at 337 AM MDT Thu Mar 26 2026

A few adjustments have been made to the near-term forecast based
on the latest guidance and the upcoming cold front. To start, the
Red Flag Warning has been trimmed with Lincoln County now
excluded, as there`s growing confidence in a lack of overlap
between the low humidity (through early afternoon) and the
stronger frontal and post-frontal winds (mid-afternoon onwards).
Patchy blowing dust was also incorporated into the forecast across
the plains for this afternoon.

Second, cross-sections are relatively consistent in depicting
several hours of easterly upslope flow tonight, aiding in
precipitation development for much of the I-25 corridor and
foothills. There`s still some uncertainty as to the placement of
the highest totals with convective showers possible in and around
the Denver metro, but generally the central/southern foothills
should be favored given the flow pattern. Have increased PoPs for
all areas to above 60% (higher for the foothills), as well as
projected precipitation amounts (several tenths of an inch appear
increasingly feasible for wherever we see convective and upslope
enhancements). A dusting to a couple inches of snow is within
reach for portions of our foothills, but no accumulations are
expected below 7,000 ft (though some flakes may certainly mix in).

The forecast remains otherwise on track, and no other changes of
note were made.

&&

.DISCUSSION /Through Wednesday/...
Issued at 1155 PM MDT Wed Mar 25 2026

The persistent ridge that has been responsible for the record-
breaking high temperatures across the West will flatten out and
begin to move eastward on Thursday. Lee troughing is expected to
develop over southeastern Colorado by Thursday morning ahead of an
approaching shortwave and associated cold front. Guidance shows 700
mb temperatures gradually cooling throughout the day, and by about 6
PM, we are looking at a 12-16C decrease compared to today
(Wednesday). There are still some uncertainties with Thursday`s
temperature forecast, as a fairly wide spread of scenarios is
portrayed in the latest guidance, and are highly dependent on cold
front timing. After the cold front that oozed into northeastern
Colorado back in early March (3/10/26 to be exact) that never
retreated back northward through the day as models portrayed, this
forecaster is skeptical of the warmer solutions playing out, at
least across the northern portion of the forecast area. Therefore,
temperatures were blended with some of the cooler guidance along the
Wyoming/Colorado border. This does make for a fairly large
temperature gradient from the northern border (highs in the upper
60s) to our southern border (highs in the upper 80s in southern
Lincoln County), where a 22 degree temperature difference is
forecast. If the front speeds up at all, this will impact
temperatures across the lower elevations, but for now, the current
forecast does still keep some locations climbing towards another day
of record highs before the front slides south by the afternoon.
This will also allow for critical fire weather conditions to develop
over portions of our southern forecast area where a Red Flag Warning
is in place from 11 AM to 6 PM (more in fire discussion below).

Gusty winds and increased moisture will accompany the front, with
gusts between 35-45 mph possible as it passes. Light
precipitation will be possible as there will be enough moisture
and northeasterly winds will provide upslope conditions to the
Front Range Foothills and Palmer Divide. Can`t rule out the
possibility for some lightning or even some dry lightning where
instability is greatest (SBCAPE ranges from 150-300 J/kg)
generally along the foothills, adjacent plains, and Palmer Divide.
Will have to watch for potential fire starts if we do see any
lightning strikes as fuels remain dry and available after the
recent stretch of record breaking temps and dry conditions (see
more in fire weather discussion below). Temperatures will drop low
enough to even allow for a dusting of snow overnight for the
higher foothills and Front Range Mountains, with some flurries
possible for the lower elevations late Thursday night/early Friday
morning.

Temperatures will cool significantly on Friday, with high
temperatures finally expected to be a few degrees below normal for
the lower elevations, while the mountains and mountain valleys stay
about 5 to 20 degrees above normal. Cross sections show low level
moisture sticking around through the day Friday, with precipitation
shutting off by the afternoon. While the cooler temperatures and
precip are a welcomed change, nothing significant is expected with
this system that would make any dent in our lacking snowpack or
worsening drought. Expecting total QPF between .05" for the plains,
and up to .2" for the higher elevations.

The perpetual warming and drying cycle will start over again on
Saturday as the upper-level ridge rebuilds over the West. This will
start to bring temperatures back up to well-above normal values
through next week, leading to elevated to critical fire weather
concerns returning to portions of the forecast area.

Signs are pointing to a significant pattern change by early next
week as the upper-level ridge finally shifts into the eastern CONUS.
The exiting high pressure looks to wrap some Gulf moisture around
itself and into Colorado by Monday, and by midweek a trough looks on
track to bring Pacific moisture into the Rockies.

&&

.AVIATION /12Z TAFS through 12Z Friday/...
Issued at 525 AM MDT Thu Mar 26 2026

Complex and quite dynamic forecast in store for the terminals
through Friday. Drainage flow is holding steady at this hour, but
should gradually weaken through the morning and likely give way to
increasingly westerly and then northerly flow. Latest guidance has
accelerated the transition to NNE/NE wind, now forecast to occur
closer to 16-17Z (earliest at KDEN). Expect the NE flow to
strengthen through the afternoon with the FROPA (high confidence
with this component of the forecast), with peak gusts 25-35 kts
past 21-22Z.

Increasing mid-level moisture mid-afternoon, together with slight
instability and the arrival of the cold front, look to promote
ISO-SCT high-based -SHRA or -TSRA activity. Given initially dry
low-levels, it`s possible these could produce variable and erratic
outflows in their vicinity. This is not reflected in the TAFs
given the assumption that the gusty post-frontal winds would be
favored to win out, but the potential is there nonetheless. An
additional consideration during the mid to late afternoon
timeframe will be the potential for a brief period of BLDU, mainly
for KDEN, accompanying and immediately behind the FROPA.

The next item of concern will be the anticipated arrival of low
stratus and CIGS in the evening. This is generally favored to
occur beginning near 03Z Fri, +/- about 2 hours, though with some
uncertainty as far the coverage of any -SHRA and thus persistence
of CIGS in the 020-040 range. The higher probabilities for SHRA
will arrive during the early morning hours, namely past ~08Z and
continuing past daybreak. Over time, suspect most of the shower
activity should migrate closer to the foothills and away from
KDEN, but regardless there will be heightened potential for vis
reductions of 4-6SM and periods of CIGS 008-015 at all of the
terminals.

&&

.FIRE WEATHER...
Issued at 1155 PM MDT Wed Mar 25 2026

Temperatures will warm into the upper 80s across the southern
portion of our lower elevations on Thursday that will coincide
with relative humidity values in the 10-15% range and increasing
northwesterly winds. Additionally, South Park will see gusty west
winds throughout the day with relative humidities dropping into
the low to mid teens. A cold front is expected to bring a wind
shift to the northeast and wind gusts between 35-45 mph during the
afternoon/evening hours. Therefore, a Red Flag Warning is in place
for South Park and far eastern Elbert and southern Lincoln
Counties from 11 AM to 6 PM Thursday. Moisture is expected to
increase behind the front that will see vast improvements to
relative humidity recoveries, though winds will take a little
longer to see the improvements, diminishing from north to south.
There is potential for a few lightning strikes with the frontal
passage, mainly for the foothills and adjacent plains. With only
light precipitation expected, dry lightning can`t be ruled out
that could spark new fires as fuels remain very dry and available
after the recent period of record breaking heat and dry conditions.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 11 AM this morning to 6 PM MDT this
evening for COZ214.

&&

$$

UPDATE...BRQ
DISCUSSION...9
AVIATION...BRQ
FIRE WEATHER...9

NWS BOU Office Area Forecast Discussion