324
FXUS65 KBOU 240013
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
613 PM MDT Mon Jun 23 2025

.KEY MESSAGES...

- Cooler with more moisture and scattered to likely showers and
  thunderstorms Monday through Wednesday.

- Severe storms possible across the plains Tuesday, with large hail
  and gusty outflow winds being the main threat.

- Drier Thursday through Sunday with warming temperatures and only
  isolated late day showers and thunderstorms.

&&

.DISCUSSION /Through Monday/...
Issued at 258 PM MDT Mon Jun 23 2025

Skies over the urban corridor certainly had a case of the
"Mondays" today, with a blanket of low clouds remaining in place
through the morning. With the low ceilings in place, solar
heating has been limited, resulting in a later start to
convective initiation than previously expected. While ACARS
soundings still show a hefty cap in place over the plains at the
time of this writing, some cumulus have started to show some
upwards growth over portions of the high country, with even a few
flashes of lightning seen in the latest satellite imagery.
Guidance has been persistent in showing that storms will
eventually make their way off the higher terrain, but we still
have a few hours to go before this is expected to occur. Due to
the delay, higher PoPs were pushed back a few hours this forecast
package, with increasing PoPs now expected around 0Z (6PM) for
the urban corridor, before spreading eastward through the
evening. The SPC has put southern Lincoln County in a Marginal
Risk for severe storms this evening, with damaging outflow wind
gusts and marginal sized hail being the main threats.

Southwesterly flow aloft will be in place on Tuesday, with a near
100 kt jet crossing the Rockies from SW to NE, with the forecast
area expected to be in decent proximity to it`s right entrance
region, though not under its strongest influences. A disturbance
in the 500 mb flow is expected to traverse the Rockies Tuesday,
providing lift come the afternoon. At the 700 mb level, Gulf
moisture will be pulled into eastern Colorado as it wraps around a
high over the southeastern US. Dewpoint temperatures are expected
to climb into the 60s, and with inverted-v forecast soundings
showing MLCAPE between 900 to 1000 J/kg, mid-level lapse rates
surpassing 7 C/km, and DCAPE over 1000 J/kg, severe storms will be
possible for our lower elevations for the afternoon/evening. With
marginal shear being the limiting factor for more organized
storms to develop, hail and gusty outflow winds are the main
threats with these storms, with tornadoes having the lowest
expected hazard potential, yet can`t be ruled out. We are
expecting to see convection develop early afternoon, with severe
storms possible across the urban corridor and Palmer Divide first,
before pushing eastward through the afternoon and evening. The SPC
has put the majority of our lower elevations in a Slight Risk for
tomorrow, for concern of storms capable of producing 2"+ hail and
winds surpassing 60 mph.

Unsettled weather will continue on Wednesday afternoon, with
isolated to scattered afternoon thunderstorms likely initiating
over the mountains and pushing east onto the plains once again.
There will still be a chance for a few more organized storms to
develop, but the severe threat is expected to be less than
Tuesday`s.

Warmer and drier conditions are expected to return for the latter
half of the week, with 90s returning to the lower elevations by
Friday.

&&

.AVIATION /00Z TAFS through 00Z Wednesday/...
Issued at 542 PM MDT Mon Jun 23 2025

Currently, there is a boundary over APA and just west of DIA,
which is bringing in NW winds. This should stick around for the
next couple of hours. Showers/thunderstorms are moving across the
foothills and onto the plains, and could arrive to APA and DIA
closer to 01/02Z. Gusty VRB outflows up to 30 kts. are still
expected with the most intense storms.

Winds should transition to E/SE after storms move out of the area.
Low ceilings will return tonight, with MVFR conditions as early as
07Z. There is a chance for brief IFR conditions between 12Z and
14Z, before gradually improving by 15Z.

Another round of thunderstorms are likely for all TAF sights, so
have TEMPO starting at 19Z. However, this will be dependent on the
ceilings clearing out for daytime heating.

&&

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

&&

$$

DISCUSSION...Bonner
AVIATION...Ideker