573
FXUS65 KBOU 281114
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
514 AM MDT Sat Jun 28 2025

.KEY MESSAGES...

- Hot today with a slight chance of afternoon showers and
  thunderstorms.

- Cooler Sunday and Monday with higher coverage of storms and a
  threat for some of these storms to be strong to severe.

- Early indications are showing a wet Fourth of July.

&&

.DISCUSSION /Through Friday/...
Issued at 237 PM MDT Fri Jun 27 2025

Radar shows isolated showers and storms this afternoon mainly from
Monument Hill to Brush. Radar is also picking up many small
microbursts under these showers and storms. Soundings show a
mixed layer up to around 600 mb and the SPC mesoanalysis page
shows DCAPE around 1,600 j/kg across the eastern plains. Both of
these would indicate storms are capable of producing gusts up to
50 mph with isolated 60 mph wind gusts. Small hail is possible as
well although severe hail is not expected.

Saturday will be nearly a repeat of Friday. Isolated storms will
form in the afternoon and with healthy DCAPE values, gusts up to
50 mph will be possible out of storms. The only changes for
tomorrow are that the temperatures will be a degree or two warmer
and there may be a slight decrease in coverage of showers and
storms due to warmer air aloft.

Models have major disagreements about a cold front moving through
on Sunday. Some models barely have any sign of a cold front and
keep highs around 90 across the plains. Other models show a rather
strong cold front with highs in the low to mid 80s across the
plains. How strong this front ends up being will determine the
location and strength of storms. If the front is stronger, there
will be higher upslope wind speeds and dew points close to 60
degrees. This could lead to strong to severe storms that form
closer to the I-25 corridor given mixed-layer CAPE around 2,000
j/kg. The limiting factor will be deep layer shear in that
scenario as values may only be around 30-35 knots. If the front is
weaker, there will be less instability and upslope flow. This
would lead to lower coverage of storms and would keep the severe
threat closer to the CO/NE border. At this time, the scenario with
the stronger front is favored and highs were decreased slightly
and PoPs were increased slightly.

On Monday, there will be easterly winds throughout the day across
the plains that will bring healthy moisture up to the foothills
and I-25 corridor. This upslope flow with healthy moisture will
lead to good coverage of storms (50-70% coverage) in the foothills
and southern I-25 corridor. Some storms could be strong to severe.

An upper level ridge will be directly over Colorado on Tuesday and
Wednesday. This will lead to warming and drying conditions. With
that being said, isolated afternoon showers and storms will be
possible mainly over the higher terrain.

The aforementioned ridge will move eastward towards Kansas on
Thursday and Friday as an upper level trough will move over the
Intermountain West. In between these features, the southerly flow
will draw up moisture from the Gulf of California. This moisture
along with slight upslope forcing ahead of the trough, will lead
to scattered to widespread coverage of showers and storms each day.
Unfortunately, the Fourth of July could be a wet one this year.

&&

.AVIATION /12Z TAFS through 12Z Sunday/...
Issued at 510 AM MDT Sat Jun 28 2025

SSE winds will become more SSW in the next hour or two. By 17z
expect a light north or NNE component will may become more NE
by 21z. Winds will then transition to SSE by 02z and then
SSW by 06z.  There is a 10% chance of a high based shower/virga
between 21z and 02z which could produce brief gusty winds up to
30 mph if they were to develop.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Danielson
AVIATION...RPK