148
FXUS65 KBOU 312336
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
536 PM MDT Sun May 31 2026

.KEY MESSAGES...

- A chance for strong thunderstorms returns for Monday and Tuesday
  afternoons, with locally heavy rain possible.

- Trending warmer and drier by the end of the week.

&&

.DISCUSSION /Through Sunday/...
Issued at 247 PM MDT Sun May 31 2026

It is a sunny afternoon for most of Colorado today, with near-
seasonable temperatures ranging from the low 60s over the mountains
to the low 80s at low elevations. Satellite imagery shows increasing
cloud cover over the high terrain, but most areas should remain dry
with only a small chance (15%) for a light shower over the highest
mountain peaks and western slopes.

The latest SPC convective outlook for tomorrow has placed a slight
(2/5 level) risk over the NE Colorado plains extending west into
Weld County and DIA, and a marginal (1/5 level) risk over the
foothills. East to southeast flow at the low levels will advect
dewpoints in the 40s-50s into the east Colorado plains and Denver
metro area by the early afternoon hours. High-res ensemble guidance
suggests precipitable water (PW) values in the 90th percentile of
climatology will be in place Monday afternoon through Tuesday
evening, with values over the easternmost counties of our CWA
exceeding 1.0 in. PW values at times. A decent amount of shear (40-
50 kt bulk shear), curved hodographs, 0-3km SHR ~100 m^2/s^2, and
upslope enhancement will provide an environment that will be
conducive to a few strong supercells that will be able to produce
large hail and strong winds. From a thermodynamic perspective, CAPE
will extend vertically into the hail growth zone, and steep mid-
level lapse rates >7.0 C/km will also be present. There is also a
small (30% chance) probability that showers and thunderstorms could
linger into the late evening or early morning hours of Tuesday,
aided by strong low-level moisture advection.

The convective environment for Tuesday afternoon will be very
similar to Monday`s setup. The primary difference in Tuesday`s setup
will be weaker shear, which will limit the potential for a more
discrete storm mode. Monday evening`s convection will also pose
additional challenges for convective initiation on Tuesday given the
increased chance for low stratus or fog in the morning, and a more
capped environment to begin with. However, high-res model guidance
suggests CAPE values exceeding 1500-2000 J/kg and 700-500mb lapse
rates greater than 8.5 C/km, which would support another afternoon
of severe hail potential if any CIN is overcome.

Looking ahead, daily chances for afternoon showers and weak
thunderstorms will persist through next Sunday. Upper level flow
remains weak and there is no strong signal for synoptic forcing.
Long-range ensembles suggest ridging setting up over the central
U.S. Plains by Tuesday afternoon, and a return to zonal flow to
start the weekend. Temperatures will generally trend above normal,
with 90-degree afternoon highs becoming increasingly likely for
Saturday and Sunday over the Denver area.

&&

.AVIATION /00Z TAFS through 00Z Tuesday/...
Issued at 530 PM MDT Sun May 31 2026

VFR will occur throughout the TAF period. Light and somewhat
variable winds have been the main story this afternoon. Given the
latest satellite and hi-res modeling trends, have included a
prob30 for this evening (1z to 5z) for the possibility of some
virga showers with gusty outflow winds of around 25 kts. There is
a low chance (15%) that sprinkles could occur early Monday
morning between 6z and 12z, mainly near and east of KDEN and
KAPA.

A weak cold front will push through overnight giving way to NE
winds for Monday morning and some mid-level clouds. Winds will
turn easterly to southeasterly on Monday afternoon with the
chance for showers and thunderstorms starting around 20 to 21z
from west to east across all three terminals. Any
shower/thunderstorm could bring cloud decks below 10,000 feet AGL
and gusty winds of around 30 kts. Rain chances will wind down
around 2z to 4z tomorrow evening.

&&

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

&&

$$

DISCUSSION...AA
AVIATION...MV

NWS BOU Office Area Forecast Discussion