459
FXUS65 KBOU 280837
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
237 AM MDT Sun Jun 28 2026

.KEY MESSAGES...

- Widespread and prolonged critical fire weather conditions will
  be present in the high country through Monday due to warm, dry
  and windy conditions.

- Little change in the forecast pattern through the middle part of
  next week. The only exception will be for a chance of
  thunderstorms over the plains on Tuesday.

&&

.DISCUSSION /Through Saturday/...
Issued at 230 AM MDT Sun Jun 28 2026

For today, WSW flow aloft will continue as an upper level trough
extends from the nrn Rockies into the Great Basin.  Cross-sections
show very litte moisture embedded in the flow, so expect dry
conditions to remain over the area, with gusty winds over the
high terrain. A weak cool front associated with convection over
the nrn plains was moving across nern CO early this morning. By
aftn, will likely see a Denver cyclone with an associated
convergence/shear zone. Low level moisture behind this feature is
lacking so don`t expect any tstm activity. Meanwhile, high temps
this aftn may be altered some as readings to the north and
northwest of the Denver cyclone stay in the upper 80`s to lower
90`s while areas to the south and east rise into the mid to upper
90`s. As for smoke, from the fires over UT and wrn CO, latest
HRRR seems to clear it out today but then increases it again
tonight, especially across portions of the higher terrain.

For tonight, another round of convection may occur over portions of
ern WY and wrn NE which may send another outflow boundary across
nern CO overnight.  However, don`t expect any tstm activity as the
airmass over nern CO will be capped.

On Mon, an upper level trough will extend from the nrn Rockies into
California.  This will allow for WSW flow aloft to remain over the
area with dry conditions over the high terrain.  Across nern CO low
level moisture is still lacking and with a cap in place, tstm
chances look minimal across the plains.  Meanwhile, 850-700 mb temps
are slightly cooler so aftn highs should be a few degrees cooler
across the plains.

For Tue, SW flow aloft will continue as a disturbance moves from the
Great Basin into Wyoming by Tue night.  At the sfc, the low level
flow will become S/SSE across the plains.  As a result, this will
allow some return of lower level moisture by aftn with a pseudo
dryline setting up over the plains.  Analysis of soundings, show
there is still a fairly decent cap in place, so not sure about
how much tstm activity there will be over the plains during the
aftn into the evening hours. Thus have kept in 20-30 percent pops
over the nern plains. Across the higher terrain it still looks
mainly dry.

Looking ahead to Wed and Thu, SW flow aloft will continue.  At the
sfc, low pres will extend from ern WY into ern CO with a pseudo
dryline east of the I-25 Corridor.  Low level moisture will be over
the plains, however, there still appears to be a decent cap in place
both days which may keep tstm activity minimal despite decent
SBCAPE.  Over the higher terrain, there will be some mid level
moisture embedded in the flow so can`t completely rule out some
isold high based showers or tstms.  Highs both days will be in the
90`s across the plains.

By Fri, the flow aloft will be WSW as a weak upper level trough
moves across the nrn Rockies.  At this time, it looks mainly dry
with highs remaining in the 90`s across nern CO.

&&

.AVIATION /06Z TAFS through 06Z Monday/...
Issued at 1104 PM MDT Sat Jun 27 2026

A weak cool front will move across the area between 08z and 09z
with a brief shift to north winds. By 10Z winds will be light
and variable. On Sun, winds will become S to SE by 14z, however,
it`s not clear as to wind directions by 18z. It`s certainly
possible a Denver Cyclone will develop with a boundary bisecting
the area thru the aftn. As a result may see varying wind
directions at DIA and BJC. APA will probably have a south wind by
16z which will become more SW by 20z with gusty winds at times.
For now, have shown the Denver Cyclone and associated boundary to
stay north of DIA so have kept gusty south winds by 18zx which
will become more SW by 21Z. If Cyclone and boundary stay south of
DIA then winds may have a more east or northeast direction in the
aftn. Finally, regarding smoke from fires over UT and wrn CO,
latest HRRR moves most of it to the northeast of the area by 12z
and doesn`t move it back into the area until Sun night.

&&

.FIRE WEATHER...
Issued at 230 AM MDT Sun Jun 28 2026

Critical fire conditions will continue over the higher terrain
today, with sustained southwesterly winds of 15-30 mph along with
a few gusts of 35-45 mph. There may be some very marginal
improvement to RH across North Park, though a majority of the Red
Flag Warning area will still see 10-15% RH during the afternoon
hours.

While a cold front is expected to bring some relief Sunday night
(particularly with respect to humidity recovery), no precipitation
or substantial cooling is expected during the week. Additional
elevated to critical fire weather conditions are expected each day
next week, with additional Fire Weather Watches likely needed for
at least Monday. Fuels status may also need to be re-evaluated
for areas that did not see significant precipitation over the last
week or so.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 11 AM this morning to 9 PM MDT this
evening for COZ211>214-216-218.

&&

$$

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

NWS BOU Office Area Forecast Discussion