189
FXUS65 KBOU 302339
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
539 PM MDT Mon Jun 30 2025

.KEY MESSAGES...

- Summer heat returns Tuesday and Wednesday, still a few storms
  mainly over the mountains.

- Storm chances increase Thursday.

- Scattered thunderstorms and normal temperatures are expected for
  the Fourth of July and Independence Day weekend.

&&

.DISCUSSION /Through Monday/...
Issued at 217 PM MDT Mon Jun 30 2025

A few showers and thunderstorms had developed in the more
unstable airmass over the mountains this afternoon, but so far
coverage has been a little less than anticipated. We still think
South Park will end up with the highest coverage late this
afternoon into early evening. Some late day instability/weakening
CIN may allow a few showers/isolated storms to move onto the
adjacent plains south of I-70 (10-30% chance) early this evening.

For Tuesday and Wednesday, the center of the upper level ridge
will shift slowly east across Colorado, bringing a return of
summer warmth and a general decrease in shower/storm coverage.
However, there will be some moisture stuck under the ridge
Tuesday, and enough westerly flow aloft yet to allow a few high
based showers/storms to push east from the mountains onto the
plains. MLCAPE is limited (outside of the northeast corner) so
generally gusty winds and lightning would be the main threats. The
far northeast corner would have a low threat of severe with
MLCAPE 1000 J/kg or greater there. On Wednesday, the upper level
ridge is expected to shift slightly eastward into eastern
Colorado. Thus, with little/no westerly flow aloft it will be very
hard to get a storm on the plains. Mountain areas should still
see isolated to scattered late day convection.

For Thursday, we`ll still on track to see a plume of sub tropical
moisture move northward. This occurs in deeper southerly flow
developing between the upper level high shifting into the Central
and Southern Plains and a weak trough lifting northward across
the Desert Southwest. As a result, Thursday`s convective intensity
and coverage is expected to increase, with likely the best chance
(40-60%) of rain this week.

As discussed yesterday, there is also a threat that the
approaching trough from the southwest could end up being a player
on Independence Day weather. However, the latest trends over the
last 24 hours are for a faster and stronger ejecting trough
Thursday and Thursday night. If this occurs then that shortwave
could literally steal much of the thunder from Friday`s
(Independence Day) forecast. It`s still too early to tell, but the
latest trends would suggest a decrease in storm coverage and our
PoPs have been adjusted accordingly with this latest guidance.

Typical summer weather is then expected through next weekend, with
temperatures at/just above normal levels and a few rumbles of
thunder each afternoon and evening.

&&

.AVIATION /00Z TAFS through 00Z Wednesday/...
Issued at 539 PM MDT Mon Jun 30 2025

Scatter/broken cumulus clouds at around 6000 feet to linger
through about 03Z before they dissipate. Thunderstorms so far have
been confined to the higher terrain southwest of Denver. Storms
are expected to stay well south of DEN, but there still is a
slight chance (10-20%) outflow from the current convection could
produce a brief shower or storm through 03Z.

Light east to southeast winds to slowly transition to the south to
southwest after 06Z. For Tuesday, southerly winds become weak by
16-18Z. There will be a better chance for showers/storms Tuesday
afternoon with about a 30 percent chance about 21Z. However,
outflow winds will be likely.

&&

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

&&

$$

DISCUSSION...Barjenbruch
AVIATION...Meier