258
FXUS65 KBOU 230005
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
605 PM MDT Fri May 22 2026

.KEY MESSAGES...

- Scattered showers and thunderstorms through this evening, mainly
  south of I-70. Remaining cool.

- Warmer and drier this weekend, with only isolated showers and
  storms possible each afternoon/early evening.

- Remaining mild next week, but scattered afternoon and evening
  showers and storms expected most days.

&&

.DISCUSSION /Through Friday/...
Issued at 108 PM MDT Fri May 22 2026

Satellite imagery shows a shortwave moving through eastern Utah
and western Colorado, with weak QG lift arriving during peak
heating. This will support another round of showers and a few
thunderstorms across portions of our forecast area - strongly
favoring the Palmer Divide. That area will be under the influence
of favorable frontogenesis and a right entrance region of a weak
upper level jet well into this evening. Therefore, this batch of
showers and isolated weak storms (MLCAPE less than 300 J/kg)
should be rather persistent. Denver will likely be on the edge of
the showers, with the southern/western portions seeing more rain
while the chances of anything appreciable diminish into the
northern suburbs and points north to Fort Collins. Rain showers
will eventually push east of the I-25 Corridor by midnight and
then gradually diminish/end overnight over the adjacent plains of
the Palmer Divide.

Ridging will occur this weekend with warmer temperatures and
drier conditions. However, there is still enough moisture to
support development of a couple higher based showers and storms
over the mountains and Palmer Divide/Cheyenne Ridge area in the
afternoon. Also, enough low level convergence along the developing
lee trough Saturday could support a couple storms over the
eastern plains. Highs are expected to warm from the lower to mid
70s on the plains Saturday, into the lower to mid 80s by Sunday.

The upper level ridge is still forecast to push east of the
forecast area on Monday as upper level low moves into southern
California. This will support a gradual increase in precipitable
water, and thus convective development will likely turn up a
notch. By Tuesday, further moisture advection occurs in deeper and
stronger southerly flow, and there`s even a hint of weak negative
tilt from an ejecting shortwave. This will support increasing
storm chances, as well as the threat of a few strong/severe
storms.

From there, ensembles support a blocking ridge developing from the
upper Midwest/western Great Lakes into southern Canada. While
details vary considerably between runs at this point, it appears
we`ll still be mostly in southerly flow or have sufficient
moisture around to support scattered and daily afternoon showers
and storms through much of next week. Temperatures should average
slightly above normal.

&&

.AVIATION /00Z TAFS through 00Z Sunday/...
Issued at 557 PM MDT Fri May 22 2026

Radar shows increasing coverage of showers over the southern and
western Denver metro. These showers are already impacting APA and
may briefly move over BJC and DEN. Lightning strikes have been
reported over the Palmer Divide so there is a chance lightning
occurs near APA but that chance seems to be getting lower as the
event goes on. Ceilings should generally stay above 7,000 feet at
all terminals. The showers will eventually dissipate tonight and
VFR conditions are expected through Saturday.

Winds will be light during the day on Saturday. The only possible
weather impact will be a 20-30% chance of isolated afternoon
showers over all terminals. The instability is limited tomorrow
so showers are unlikely to form but if they do, gusty winds up to
30 knots would be possible.

&&

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

&&

$$

DISCUSSION...20
AVIATION...Danielson

NWS BOU Office Area Forecast Discussion