965
FXUS65 KBOU 312054
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
254 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 /18Z TAFS through 18Z Monday/...
Issued at 1143 AM MDT Sun May 31 2026

VFR to prevail through the TAF period. West winds with gusts to 25
knots are just northwest of DEN and north of BJC. Through 20-21Z,
these gustier winds will be possible. Winds are then expected to
turn north and then northeast 22-24Z. Northeast winds will then
prevail through the evening and possibly overnight due to a weak
cold front moving through. Mid level clouds will increase behind
the front after 06Z with a few showers possible northeast of DEN
early Monday morning. Winds turn to the southeast Monday morning
advecting moisture into the area. This will lead to a chance for
thunderstorms after 21Z Monday.

&&

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

&&

$$

DISCUSSION...AA
AVIATION...12

NWS BOU Office Area Forecast Discussion