859
FXUS65 KBOU 262020
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
220 PM MDT Sat Apr 26 2025

.KEY MESSAGES...

- Isolated late afternoon and evening thunderstorms across the
  plains.

- Warm and windy Sunday with critical fire weather conditions in
  the afternoon across the plains and South Park.

- Seasonal conditions next week with a chance of afternoon showers
  or thunderstorms most days, especially in the high country.

&&

.SHORT TERM /Through Sunday/...
Issued at 139 PM MDT Sat Apr 26 2025

SW flow aloft will be over the area tonight as an upper level low
moves into Nevada by 12Z Sun. Currently, there is a well defined
boundary which has been moving slowly north across portions of the
Denver area into central portions of Weld county. MLCAPE is
around 500 j/kg where low clouds have eroded this aftn, however,
there is still a capping inversion in place. Still can`t rule out
a few isold storms developing, along this boundary, thru the early
evening hours. Another possible area of tstm development would be
over srn Lincoln county with a few storms moving across the rest
of Lincoln county this evening. Confidence in either scenario
isn`t real high so will leave pops mainly in the slight chc
category.

On Sun, an upper level low will move into the Great Basin with stg
SW flow aloft over the area.  At the sfc, low pres will intensify
along the front range with gusty south to southwest winds across the
area.  There will be a chc of aftn showers along with an isold tstm
over the higher terrain where some mid level moisture will combine
with decent lapse rates.  Across the plains it will be windy and
dry.  Highs across the plains due to downslope lo level flow will
rise into the upper 70s to lower 80s.

&&

.LONG TERM /Sunday night through Saturday/...
Issued at 139 PM MDT Sat Apr 26 2025

Temperatures will be 10-15 degrees cooler on Monday in the post-
frontal airmass, and the drier air will be relegated closer to the
surface. With marginal instability in place despite cooler
conditions, a few high-based showers and weak thunderstorms could
occur in the afternoon. By late afternoon and evening, another
front will bring breezy north winds to the plains and sustain a
chance of showers. The southernmost of our lower elevations (south
of the I-70 corridor) could still see humidity lower into the
low/mid teens in the afternoon, with lingering fire weather
concerns as a result.

We`ll remain on the cooler side Tuesday with only minor changes in
temperatures, and a generally stable environment outside of the
high country which should keep afternoon precipitation changes
confined mostly to our mountains and foothills.

Synoptically, the pattern remains troughy on Wednesday, albeit
quite disorganized. Although instability doesn`t look too
impressive, PWAT values will be healthier and between 150-200% of
normal. With a surface front progged to descend into Colorado as
well, it suggests better chances for precipitation relative to
previous days, and ensemble mean QPF fields validate this.

It`s tough to draw any overly distinct details in the forecast
beyond Wednesday. We`ll likely still hold on to a fairly
progressive upper-level pattern and some moisture and instability
for Thursday, with signs somewhat favoring a transition to ridging
and a warmer/more stable environment Friday into Saturday.

&&

.AVIATION /18Z TAFS through 18Z Sunday/...
Issued at 1112 AM MDT Sat Apr 26 2025

Gusty south winds remain south of DIA and radar really hasn`t
shown much of a northward push to the boundary the past hour.
Latest HRRR has delayed the gusty south winds until 21Z as weak
circulations develop along the boundary. As far as tstms,
soundings show a decent cap in place, however, there could be
enough forcing along the boundary to generate an isold storm
between 21z and 00Z. For tonight, should see gusty south winds
which may turn light west by 10z or 11z. Threat of stratus/fog
late tonight should be much lower than this morning. Winds will
become gusty from the SSW by 15Z on Sun.

&&

.FIRE WEATHER...
Issued at 139 PM MDT Sat Apr 26 2025

Critical fire conditions will develop by late Sunday morning and
early afternoon across most of the plains and across South Park.
Gusty south to southwest winds of 20 to 30 mph with gusts to 45
mph will occur with humidity levels dropping to 10 percent.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 11 AM to 8 PM MDT Sunday for COZ214-
240>247-249.

&&

$$

SHORT TERM...RPK
LONG TERM...Rodriguez
AVIATION...RPK
FIRE WEATHER...RPK