Severe Thunderstorm Warning 124, NWS Denver/Boulder, CO

Area Forecast Discussion
National Weather Service Denver/Boulder CO
239 PM MDT Mon Jun 22 2026

.KEY MESSAGES...

- Strong to severe storms expected for the plains this afternoon,
  producing large/very large hail, gusty winds, and possibly a
  weak landspout.

- Additional rounds of severe storms expected Tue-Wed, with
  increasing potential for impacts to I-25 corridor and localized
  flash flooding. Temperatures to remain slightly below normal.

- Elevated to locally critical fire weather conditions in the
  mountains most afternoons, increasing in severity this weekend
  under building heat and strengthening winds.

- Drier and considerably hotter for the lower elevations starting
  Friday.

&&

.DISCUSSION /Through Monday/...
Issued at 230 PM MDT Mon Jun 22 2026

Current observations show thunderstorms starting to develop over the
east Colorado plains. The Denver Convergence-Vorticity zone (DCVZ)
is currently situated just east of the Denver metro, which is
providing an area of enhanced surface vorticity. Bulk shear values
over eastern Colorado are in currently in the 40-50KT range,
although the better 0-3 km storm relative helicity (SRH) values are
located over our northeastern CWA counties. Nevertheless, the
aforementioned parameters, combined with precipitable water (PW)
values around 0.70"-1.00", and steep lapse rates (~8 C/km), will
support the development of supercells able to produce large hail,
gusty winds, and weak landspouts. Localized flash flooding will also
be a concern with any slow-moving storms this afternoon, as well
as over the next few days, especially over areas with leftover
soil moisture from the previous day's storms. While the primary
thunderstorm threat will likely be out of the area by 7pm,
additional elevated thunderstorms cannot be ruled out later in the
evening, as we have seen occur over the last few evenings where
outflows from farther east have triggered convective initiation.

A cold frontal passage is expected to bring northerly flow into the
region Tuesday morning, as well as the potential for some patchy low
clouds. Severe thunderstorms will be possible again tomorrow.
However, the initial convective environment will face a few more
challenges earlier in the day, given the slightly drier surface
dewpoints behind the front, and northerly winds, as opposed to the
moister southeasterly flow that is in place today. However, the
shear profile tomorrow looks to be more favorable for rotating
updrafts, with high-res model soundings showing curved hodographs,
and a few isolated but longer-lived supercells. All hazards will be
possible with any storms that develop tomorrow afternoon and
evening, although the primary concern is very large hail (>
2.00").

Wednesday and Thursday will bring more rounds of severe weather
potential (mainly hail), driven by zonal flow aloft and low-level
moisture advection from the southern U.S. plains. The PW content in
place over the Denver area through most of this week is at the
90th percentile of climatology for late July, which is when the
annual peak of PW values occurs. However, the high terrain to the
west is a different story, given that this surge in moisture will
be confined to the low elevations of eastern Colorado and the
foothills. As such, elevated to locally critical fire weather
conditions will persist over the mountains and high valleys where
relative humidities will drop into the teens and single digits
each afternoon, with winds gusting to 20-35 mph.

Widespread critical fire weather conditions are still on track to
arrive on Saturday as an approaching upper level trough pushes
the moist airmass in place eastwards while also causing winds to
increase due to the tightening pressure gradient.

&&

.AVIATION /18Z TAFS through 18Z Tuesday/...
Issued at 1211 PM MDT Mon Jun 22 2026

VFR conditions are expected throughout the forecast period. The
Denver Cyclone moved directly over KDEN between 15z and 17z this
morning. TDEN shows that the cyclone is now located a few miles to
the east of KDEN. As a result, winds have now shifted to NNW
across the entire KDEN airport property.

TSRA development is still on track for this afternoon with KAPA
having the highest chance. ACARS soundings show a cap still in a
place, so have pushed TSRA chances back to start at 19z at KAPA
and 20z at KBJC and KDEN. All three terminals have the chance to
experience gusty outflow winds this afternoon of about 25 to 30
kts from thunderstorms as they move to the east.

By this evening, winds will stay elevated with gusts as high as 25
kts given the continued outflow enhanced winds especially at KDEN
and KAPA. At KBJC, NNW winds should stay around 10 kts for most
of the night after about 05z. A front will push through from north
to south for all three terminals between 13z and 15z tomorrow
morning with gusty winds from the north. By tomorrow afternoon,
winds should settle into a more NE direction. Showers and
thunderstorms will likely be possible especially at KDEN and KAPA
tomorrow afternoon with the threat for gusty outflow winds once
again, but there is low confidence in exact placement of
thunderstorms at this time.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from noon to 8 PM MDT Tuesday for COZ212-213-
217.

&&

DISCUSSION...AA
AVIATION...MV

Preliminary Local Storm Report
National Weather Service Denver CO
518 PM MDT Mon Jun 22 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0512 PM     Landspout        3 WSW Willard           40.53N 103.54W
06/22/2026                   Logan              CO   Storm Chaser

&&

KEB

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