506
FXUS65 KBOU 011758
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1158 AM MDT Mon Jun 1 2026

.KEY MESSAGES...

- A chance for strong and severe thunderstorms this afternoon and
  again Tuesday afternoon, with locally heavy rain possible.

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

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

&&

.DISCUSSION /Through Sunday/...
Issued at 231 AM MDT Mon Jun 1 2026

Already seeing sct high based showers and a few weak tstms across
portions of nern CO early this morning.  This appears to be
associated with some mid level instability and along the srn portion
of an upper level jet.  Latest data suggest this activity will
continue thru mid morning with a few stronger storms possible closer
to the WY-NE border area.

By aftn, SW flow aloft will remain over the area as easterly flow in
the lower levels occurs behind a weak cool front.  SBCAPE over the
plains will range from 1500-2000 j/kg by aftn with a favorable shear
profile.  Sct tstms will develop near Denver by 20z and then move
rapidly ENE across the plains by 00Z.  Damaging winds and large hail
will likely occur with a few of the storms, with a brief tornado or
two possible initially, before storms consolidate into a solid line.
Meanwhile, across the higher terrain tstm coverage will be more
widely sct.  Highs today will be in the upper 70s to lower 80s
across the plains.

On Tue, the flow aloft will remain SW with the low level flow
becoming more SSE across the plains.  Once again, SBCAPE will range
from 1500-2000 j/kg with a favorable shear profile.  However, not
sure where best focus for tstms will be in the aftn.  If a Denver
cyclone were to develop, then storms may fire off the DCVZ and then
move ENE across the plains, with a few svr storms possible.  Once
again over the higher terrain expect tstm coverage will be more
isold to wdly sct.  As for highs, readings will be in the upper 70`s
to mid 80`s over the plains.

By Wed, the flow aloft will become more zonal and weaken. Meanwhile,
will still see SSE low level flow across the plains with possibly a
Denver cyclone and associated DCVZ.  SBCAPE will still be in the
1500-2000 j/kg range by aftn so there will still be some threat of
isold svr storms.  In addition, storm motions will be slower so may
see some heavier rainfall in those areas that get storms.   Across
the higher terrain, storm coverage will generally remain widely sct.
Highs over nern CO will be in the lower to mid 80`s.

For Thu and Fri, the flow aloft will remain nearly zonal as an upper
level trough moves across the nrn Rockies.  SBCAPE over the plains
will likely stay in the 1500-2000 j/kg range both days.  Overall,
focus for tstm development is hard to pinpoint this far out so will
just keep pops in the chc category.  Highs across the plains will
be in the 80`s on Thu with mid 80`s to lower 90`s by Fri.

Looking ahead to next weekend, an upper level trough is fcst to
develop over the wrn US with the flow aloft becoming more SSW.  For
now it looks drier with warmer temps.

&&

.AVIATION /18Z TAFS through 18Z Tuesday/...
Issued at 1158 AM MDT Mon Jun 1 2026

East to southeast winds have increased moisture across the area
and brought stratocumulus clouds at 3,500 to 5,000 feet. These
clouds will burn off soon as the airmass warms. This increase in
moisture will fuel thunderstorm development this afternoon
beginning around 19Z. Main time frame for a thunderstorm at DEN
will be 20Z to 23Z. Hail (possibly large), heavy rain, and wind
gusts to 50 knots will be possible under the stronger storms.
Models agree there should only be one round of thunderstorms this
afternoon, so by 22-00Z, expect storms to be east of DEN.

Low clouds will develop after midnight between 08Z and 10Z and
then linger most of Tuesday morning. Ceilings are expected to be
in the 1000 to 3000 foot range, with a slight chance (20%) of
ceilings under 1,000 feet. A Denver cyclone is expected to help
form the low clouds. Then mid morning winds become southeast. This
will end the threat of lower ceilings (~1000 feet) and slowly
erode the remaining low clouds. Another round of afternoon
thunderstorms is expected, beginning around 21Z. There`s a chance
the airmass is capped, with the best chance for this occurring
north of Denver.

&&

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

&&

$$

DISCUSSION...RPK
AVIATION...12