465
FXUS65 KBOU 021752
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1152 AM MDT Thu Jul 2 2026

.KEY MESSAGES...

- Critical fire weather conditions in South Park today and
  possibly again on Friday.

- Isolated showers and storms will form mainly over east-central
  Colorado this afternoon and evening. A couple storms may be
  strong to severe in and near Washington and Lincoln Counties.

- Near normal temperatures with scattered showers and storms on
  July 4th. These storms have the potential to impact firework
  shows.

&&

.DISCUSSION /Through Wednesday/...
Issued at 445 AM MDT Thu Jul 2 2026

Moist air advected westward much quicker than anticipated last
evening leading to large hailstorms and flash flooding in Weld and
Logan Counties. This heavy rain has lead to a few other affects on
the forecast for this morning. It has created a strong outflow
boundary that has produced 45 mph winds at Akron and 25 mph
northeast winds at DIA. Some low clouds have formed at the base of
the foothills which is helping humidity recover in those areas.
This is pushing better moisture higher up into the foothills than
models had forecast. The affect this may have is to reduce the
high temperatures across the plains by a degree or two this
afternoon.

A surface boundary is expected to form over the Palmer Divide
this afternoon. Most high resolution models develop a couple
storms along this boundary mainly in Elbert, Lincoln, and
Washington Counties. If storms do develop, they may become strong
to severe with large hail and damaging wind gusts possible
primarily in Lincoln and Washington Counties. This boundary will
also have enough low level vorticity and 0-3 km CAPE along it that
a landspout tornado or two could develop. PoPs were increased in
this area this afternoon and evening.

South Park will continue to have fire weather concerns today as
southwest winds will be able to mix down to the surface during the
afternoon. With gusts around 30 mph and relative humidity as low
as 6%, a Red Flag Warning is in effect. Similar conditions may
also develop on Friday although lighter winds are expected.

On Friday, warmer air aloft will move over Colorado with increased
500 mb heights. This will lead to high temperatures across the
plains in the low 90s. Light east winds across the plains will
advect better moisture into northeast Colorado by the late
afternoon and evening. Models are beginning to focus on storms
developing near Cheyenne, WY as there will be the best surface
convergence and upslope flow in that area. Some of these storms
may move southeastward into Colorado Friday evening. Friday night
may be another period with nocturnal convection as moderate
instability will exist over northeast Colorado. If an outflow
boundary were to move into the foothills it could help develop
storms over the eastern plains of Colorado. There is a lot of
uncertainty with this period, however, so PoPs were left low.

Models are converging on a solution for Saturday that has moderate
easterly winds across northeast Colorado with dew points in the
upper 50s to low 60s across the eastern plains. The combination of
upslope winds, moderate to high moisture levels, and a weak
shortwave trough will combine to create scattered showers and
storms across the majority of our forecast area. This may be
unfortunate for those trying to observe firework shows but it is
possible the storms come to an end over the urban corridor around
sunset. Otherwise, Saturday will have near normal temperatures.

Sunday and into next week will see temperatures slowly warming
with isolated showers and storms most afternoons.

&&

.AVIATION /18Z TAFS through 18Z Friday/...
Issued at 1151 AM MDT Thu Jul 2 2026

Winds are just now transitioning to diurnal easterlies, and should
gradually strengthen with a shear zone/weak cyclone developing
south of the TAF sites. Peak gusts could reach 20-22 kts. There is
already some high based cumulus southwest of the TAF sites, and
given that we expect some isolated virga we`ve introduced a
PROB30 of VRB gusty outflow winds. DCAPE is nearly off the charts
given the deep and dry subcloud layer, reaching 1600-1700 J/kg so
potential for very localized gusts to 50 kts if we fully mix, but
that`s also the greatest uncertainty as we`re still quite stable
with delayed heating after last night`s surge. Winds may very well
become VRB for a few hours 03Z-06Z if we get any convective
influence, but will otherwise lean toward a fairly normal diurnal
wind progression from SE-SSW-WSW 03Z-12Z Friday. Then back to a
diurnal easterly around 18Z-19Z Friday.

Next concern is smoke impacts. We still have marginal IMC
conditions at the start of this TAF period, but additional smoke
will arrive from the wildfires in southwestern Colorado and
southeast Utah. With the change in trajectories, smoke
concentration will be greater than the last few days and thus
could actually start impacting visibility down to ~6SM at times
through 18Z Friday.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 8 PM MDT this evening for COZ214.

&&

$$

DISCUSSION...Danielson
AVIATION...20

NWS BOU Office Area Forecast Discussion