National Weather Service Forecast Discussion

Thornton Weather Forecast   
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391
FXUS65 KBOU 260714
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
114 AM MDT Fri Jun 26 2026

.KEY MESSAGES...

- Scattered showers and thunderstorms return this afternoon, and a
  few may become strong to severe in the plains.

- Widespread and prolonged critical fire weather conditions will
  be present in the high country this weekend as warm, dry and
  windy conditions develop, continuing at times into early next
  week.

- All areas will trend warmer and drier this weekend, with little
  change into next week.

&&

.DISCUSSION /Through Thursday/...
Issued at 1234 AM MDT Fri Jun 26 2026

Our stretch of active weather will come to a close soon, but we
have one more day of afternoon thunderstorms to contend with
before truly warmer and drier conditions return. Moisture levels
do tick down slightly today, but PW values will still range
between ~0.8" over the urban corridor to around 1.10" in the
eastern plains - plenty sufficient for additional rain with any
afternoon storms. Guidance is rather variable as far as CAPE is
concerned for the urban corridor, though maintains moderate to
healthy instability over the plains. With little if any stratus
currently present over the lower elevations, and one additional
shortwave approaching from our west, suspect convection today will
be more widespread compared to what earlier model guidance had
been suggesting. Despite a decline in lapse rates and bulk shear
values, both parameters should still be sufficient to support
isolated strong to severe storms later in the afternoon and
evening, particularly for the plains. On a positive note, the
combination of recent rainfall and more subdued fire activity to
our west yesterday will result in vastly improved air quality
today, with much less smoke aloft.

We remain on track for the arrival of much warmer and drier
weather for this weekend as a ridging pattern takes hold over the
central plains. Strengthening southwest flow aloft ahead of a
trough to our west will generate hefty winds, most notable for the
high country, and drive a prolonged period of high fire danger
that will continue into early next week. Fortunately, more
abundant green-up and recent precipitation will keep those
concerns limited east of the Front Range mountains. All areas
look to remain dry through at least Monday, and temperatures
across the lower elevations will quickly rebound into the mid to
upper 90`s this weekend. If we can keep cloud (and smoke) coverage
to a minimum, we`ll likely see the hottest temperatures of the
year so far Saturday and/or Sunday.

The remainder of the week looks to be characterized by continued
above-average temperatures and generally low precipitation
chances, as Colorado remains anchored between a troughing pattern
to our west and a ridge over the plains. That said, a few
shortwaves embedded in the southwest flow regime may lead to
isolated afternoon showers or weak thunderstorms some afternoons.
Elevated to at times critical fire weather conditions will persist
in the high country given stubborn breezy winds much of the week.

&&

.AVIATION /06Z TAFS through 06Z Saturday/...
Issued at 1125 PM MDT Thu Jun 25 2026

VFR conditions favored to prevail for all terminals through the
TAF period, however FEW-SCT stratus with bases 020-050 will
continue through the night, with ~30% chance of brief BKN CIGS
through sunrise.

Drainage winds will transition to SE flow this afternoon, with
around a 30% chance of TSRA in the vicinity of KDEN/KAPA as early
as 20Z and continuing through 01Z. Gusty outflows up to 30 kts
will be possible. Expect a return to drainage in the evening with
hefty speeds exceeding 12-14 kts at KDEN/KAPA and occasionally
higher gusts.

&&

.FIRE WEATHER...
Issued at 1234 AM MDT Fri Jun 26 2026

Fire weather concerns will be limited today given increased
moisture and continued scattered showers and thunderstorms.

Much warmer, drier and above all windier weather will arrive near
midday Sunday, with the strongest winds impacting the high country
with sustained speeds approaching 25 to 30 mph and gusts as high
as 50 mph expected. With humidity descending into the low teens
during the afternoon, critical fire weather conditions will become
widespread. This warm, dry and windy pattern is set to continue
into Sunday and Monday, with only slight moderation in wind speeds
and/or humidity levels anticipated. As such, expect periods of
critical fire weather conditions to continue each day in the high
country, including both the mountains and high valleys. Greener
fuels and recent precipitation will keep fire danger much lower
across the lower elevations and much of the foothills.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 11 AM Saturday to midnight MDT Saturday
night for COZ211>214-217-218.

&&

$$

DISCUSSION...BRQ
AVIATION...BRQ
FIRE WEATHER...BRQ

NWS BOU Office Area Forecast Discussion