243
FXUS65 KBOU 030515
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1115 PM MDT Tue Jun 2 2026

.KEY MESSAGES...

- Thunderstorm chances will continue on Wednesday with isolated
  severe storms, however, locally heavy rain will be possible.

- Trending warmer and drier for Thursday and Friday with only a
  slight chance of thunderstorms.

- Afternoon high temps to reach the 90s across the plains by the
  end of the week and into the weekend.

&&

.DISCUSSION /Through Tuesday/...
Issued at 205 PM MDT Tue Jun 2 2026

Water vapor imagery shows a high amplitude ridge over the Central
CONUS with a broad upper-level low situated over the Northern
Rockies. This is keeping southwesterly flow aloft in place over
Colorado this morning. At the surface, enhanced south/southeasterly
winds have kept elevated low-level moisture flowing into eastern
Colorado overnight, with surface dewpoints currently in the 50s
across the plains. Additionally, at the base of the aforementioned
low, a shortwave is currently moving across northern Utah and
expected to move into western Colorado by this evening. We are
looking at another round of thunderstorm potential this afternoon
with the possibility for a few stronger to severe storms if
temperatures can warm enough to overcome a fairly decent cap (ACARS
soundings currently shows 213 J/kg of CIN still in place at
~12:30PM). These storms do not look to be as long-lived or as robust
as what we saw across the metro area yesterday, but MLCAPE between
1000-1500 J/kg, steep mid-level lapse rates, and 0-6km Bulk Shear
between 35-40 kts expected through the afternoon would support some
bigger (1-2") hail potential if we can tap into the greater
instability.  So far, storms that have developed over the higher
terrain have been quickly diminishing as they move eastward over the
lower elevations, which is expected to continue while the cap
remains in place. With this morning`s cloud cover keeping lower
clouds (and temps) over the Palmer Divide northward into the Denver
area, it will take some extra effort for surface heating to reach
the convective temp. It should be noted that the SPC does have the
majority of our lower elevations in a Marginal Risk (1/5 risk level)
for severe hail and wind potential. Due to this morning`s cloud
cover, have lowered today`s high temps by a few degrees, mainly for
areas along and north of the Palmer Divide, but we should still see
80s across a large majority of the lower elevations this afternoon.

If convection fails to overcome the cap this afternoon, the
aforementioned shortwave moving this way will bring another shot at
some evening showers or weaker storms as it brings an uptick in PVA
to our region through around midnight tonight.

For Wednesday, the upper-level low to our north is expected to
progress eastward across the Northern Rockies that will turn flow
aloft to a zonal pattern over Colorado. By the afternoon, a
convergence zone/dryline is expected to develop associated with a
surface low along the lee of the Rockies, with robust dewpoints on
the east side and much drier on the west side. Looks like convection
is expected to develop along this line, but there are some
uncertainties on its exact location (HRRR shows a more eastern line,
NAMNST western, and RAP splits the difference). Either way,
expecting some showers and storms to develop over the higher terrain
by early afternoon and move eastward across the plains and merging
into more of a linear mode with storms initiating along the
aforementioned convergence zone. While the more robust storms are
expected to stay to the north and east of Colorado, can`t rule out a
few stronger to severe storms developing, with the better chances
being for areas closer to the KS/NE border where the better
instability and moisture is expected, but with DCAPE values expected
to reach over 1200 J/kg for areas along the I-25 Corridor, can`t
rule out some severe gusts occurring in these locations.
Afternoon high temps are expected to be in the 80s across the
plains, 70s for the mountain valleys.

By Thursday, flow aloft will remain generally zonal as we are under
weak ridging. A brief warming trend is expected through the weekend,
with temperatures expected to warm into the mid 90s by Saturday
afternoon. The aforementioned ridge currently over the Central CONUS
will shift eastward keeping mid-level Gulf Moisture wrapping around
and into the Central Plains through the week, but pushing out of
eastern Colorado after Thursday. We should still see enough moisture
to allow for typical diurnal convection over the higher elevations
on Thursday, before drier conditions are expected for Friday and
into the weekend.

&&

.AVIATION /06Z TAFS through 06Z Thursday/...
Issued at 1109 PM MDT Tue Jun 2 2026

There have been a few microbursts late this evening due to high
based showers. Have left in a prob30 for APA until 07z to account
for this. Otherwise VFR conditions overnight.  Winds will become
southerly by 07z and then transition to more SSW by 10z.

On Thu, winds will gradually become N or NNE by 17z.  Sct showers
and tstms will be possible between 20z and 00z with brief gusty
winds up to 40 mph. Tstm activity should decrease after 00z with
winds becoming SSE.

&&

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

&&

$$

DISCUSSION...9
AVIATION...RPK

NWS BOU Office Area Forecast Discussion