663
FXUS65 KBOU 060529
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1129 PM MDT Fri Jun 5 2026

.KEY MESSAGES...

- Heating up Saturday with isolated gusty afternoon storms.

- Critical fire weather conditions to develop Saturday across
  portions of the plains, with widespread critical fire weather
  conditions expected across the plains by Tuesday and Wednesday.

- Hot weekend ahead with high temperatures soaring into the mid
  90s across the I-25 Corridor and plains.

- An early season heat wave likely Tuesday and Wednesday, possibly
  lasting into Thursday of next week. Highs near 100 degrees
  possible across portions of the plains.

&&

.DISCUSSION /Through Friday/...
Issued at 153 PM MDT Fri Jun 5 2026

Hot and mostly dry conditions will be the theme of the forecast
period, with summer-like temps expected to approach or possibly
break some records this week. With these hot and dry conditions
expected, critical fire weather is expected to be reintroduced to
the region as the prolonged heat will likely dry out much of the
green-up currently in place.

Current radar shows some weak reflectivity signatures starting to
pop over the southern portions of the higher elevations this
afternoon. Expecting a few weak high-based thunderstorms/virga
showers to pass from west to east across portions of the southern
plains and Palmer Divide through the evening, but the latest ACARS
sounding shows a lacking moisture profile for this to occur thus
far today. Looking like gusty outflows would be the most likely
outcome with these today, with the SPC mesoanalysis showing DCAPE
values approaching 1500 J/kg possible through the evening.
Afternoon high temps are still expected to be in the 80s today,
before a weekend warmup.

Colorado is expected to be under the western side of a fairly
amplified upper-level ridge on Saturday, with southwesterly flow
aloft expected to usher in a warmer and drier airmass. The main
concern for Saturday will be for the development of critical fire
weather conditions by early afternoon. After a fuel status update
from our fire partners today, we learned that despite green-up
being underway across most of the region, this winter`s drought
has kept fuels below the lushness dry and receptive, and with
relative humidities expected to drop into the low teens coinciding
with wind gusts up to 40 mph, this would meet Red Flag Warning
criteria by roughly noon. Thus, a Red Flag Warning is in effect
for areas generally just north and east of Denver from I-25
eastward along I-76 into Logan County. Outside of the low RH and
gusty wind thresholds, there is an isolated threat for some dry
lightning for portions of our northeast corner as well.
Temperatures are expected to heat up into the mid 90s across the
lower elevations, making it feel more like late July and August
than early June. The current record high for KDEN for tomorrow is
95F last set in 2018, and with the current forecast high at 93F,
we will at least get close to this record. Isolated to scattered
afternoon high-based convection is expected once again.

Afternoon high temps will warm further on Sunday with a deepening
lee trough and a slight warming of 700 mb temps. This will lead to
elevated to critical fire weather conditions developing once
again, though it`s not quite as clear-cut as Saturday`s. We are
expecting RH values to drop into the single digits around the
Denver area and southern Lincoln County, with low teens for much
of the rest of the forecast area. While we are expecting some
gusty winds for our mountain valleys and far eastern plains, at
this point, it looks like the winds will mostly cooperate and not
coincide with the areas with the lowest RH. We will likely see
some patchy localized critical fire weather conditions alongside a
fair amount of elevated fire weather conditions develop, so stay
tuned into the forecast to see if any highlights are issued.

We will see a quick break from the 90s and critical fire weather
conditions for Monday, but by Tuesday and Wednesday, it`s looking
like we will have widespread critical fire weather conditions
across the lower elevations and afternoon temps reaching 100
across portions of the plains. There are still some uncertainties
with regards to whether we see a cooldown by Thursday which will
depend on the timing of an approaching trough, but the latest GFS
ensemble is still holding onto about 12/30 members showing us
reaching 90 to 100F for Thursday afternoon, so we will have to
continue to wait and see.

&&

.AVIATION /06Z TAFS through 06Z Sunday/...
Issued at 1129 PM MDT Fri Jun 5 2026

Isolated convection had dissipated as of 05Z, with a somewhat
slower than normal transition of diurnal winds. Winds are starting
this TAF period mostly from the SE at KDEN and KAPA, but a
gradual transition to S-SW-WSW is still expected through 12Z-15Z.
KBJC will likely remain W-NW or VRB at less than 8 kts. Winds will
then become VRB for a few hours at all airports before an
expected S-SE wind develops 19Z-21Z and continues until disrupted
by afternoon convection.

We still think isolated high based showers and storms resulting
in gusty outflow winds will be the main threat again. While
coverage of the actual convection is expected to be limited,
enough threat of gusty outflow winds emanating from showers will
be high enough for at least a PROB30 and potentially TEMPO G35+
kts given DCAPE near 1400 J/kg. That could start as early as 20Z
and potentially last until 03Z. By 03Z, expect enhanced southerly
drainage winds with gusts of 20-25 kts possible at KDEN and KAPA.
VFR conditions will persist.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from noon to 7 PM MDT Saturday for COZ242>245-
248.

&&

$$

DISCUSSION...9
AVIATION...20

NWS BOU Office Area Forecast Discussion