683
FXUS65 KBOU 152150
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
350 PM MDT Tue Jul 15 2025

.KEY MESSAGES...

- Scattered storms expected tonight but severe threat is
  diminishing behind the cold front.

- Conditional severe storm threat across the I-25 corridor and
  plains on Wednesday, but low confidence at this time.

- Active pattern continues into the weekend, with scattered
  afternoon showers and storms each day. Best chance of rain
  across the Front Range/Foothills and South Park most afternoons.

&&

.DISCUSSION /Through Tuesday/...
Issued at 350 PM MDT Tue Jul 15 2025

Current satellite and radar imagery show a few different things
going on over our area. First, the upper level shortwave is
trekking over southern Wyoming, which has generated some mountain
convection over the Cheyenne Ridge and northern Front Range
mountains. However, as these showers/storms have spilled onto the
northern plains, they have quickly dissipated. This is due to the
cold front arriving a few hours early, bringing in a more stable
environment. In addition, mountain convection has initiated over
the southern Front Range mountains, producing brief gusty winds
at the surface. Modeled Skew-T soundings have steep lapse rates of
~9 C/Km and high LCLs over the higher elevation, so main threat
will continue to be gusty winds up to 40 mph this afternoon.

With the early arrival of the cold front, the overall severe
weather threat has decreased for the rest of the afternoon.
SPC mesoanalysis page shows 500-1000 J/kg of MLCAPE over the
northern/northeastern plains, with instability increasing in the
next few hours. However, with decent CIN settled over the area and
without the cold front to provide enhanced lift, storms that do
generate over the northeastern plains are expected to be sub-
severe at best, with the possibility of small hail and gusty
winds.

Wednesday looks to be more interesting severe weather wise as
another shortwave trough crosses the region- although it will be
conditional on how the morning evolves. With increased moisture
advection, a thick stratus deck is expected by Wednesday morning.
Deterministic models have dew points in the high 50s to low 60s,
so there is a chance for localized foggy conditions, especially
along the foothills. Guidance is in general consensus of 1000-2000
J/kg of MLCAPE along with 40-45 kts. of effective bulk shear,
which would favor supercell and multicell development with all
threats possible. However, the low clouds in the morning could
inhibit surface heating/instability, thus hindering the severe
weather threat. Another factor to keep in mind is the smoke from
the fires out in the west. Even if clouds clear out in the
morning, smoke in the atmosphere could keep the air slightly
cooler than their convective temperatures. Lastly, it is
important to note that if storms are able to develop, there will
be localized heavy rain, which could bring a threat of flooding.

Scattered light showers are expected Thursday, with temperatures
hovering around the mid 80s for most of the plains. With overall
lack of shear and instability, the severe weather threat is low.
By Friday, an upper level ridge will amplify over the southern
United States, bringing warmer and drier air back into our area.
Ensemble guidance is in good agreement of multiple shortwaves
traversing the area over the weekend, with increased chances of
scattered afternoon showers and storms in the afternoon hours.

&&

.AVIATION /00Z TAFS through 00Z Thursday/...
Issued at 350 PM MDT Tue Jul 15 2025

There will be scattered showers through 02z, but little impact is
expected on the Denver area terminals. There is a 20% chance of
variable winds gusting to 30 knots from a shower. More likely,
we`ll just have a steady 10 to 20 knot northeast wind.

MVFR ceilings with areas of IFR are likely late tonight into
Wednesday morning, between 08z and 16z. MVFR ceilings may continue
later than that, but clearing is likely by 20z. Thunderstorms will
develop late Wednesday afternoon, and a few severe storms are
possible. There is a 70% chance of some thunderstorm impacts, most
likely after 21z. The main threats are variable wind up to 40
knots, but gusts to 50 knots, large hail, and IFR conditions in
heavy rain are possible (10% chance).

&&

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

&&

$$

DISCUSSION...Ideker
AVIATION...Hiris