557
FXUS65 KBOU 060530
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1130 PM MDT Sun Jul 5 2026

.KEY MESSAGES...

- A few storms expected each day this week, with the highest
  probabilities shaping up for Tuesday through Thursday from the
  Front Range eastward.

- Isolated dry thunderstorms in mountains could spark new
  wildfires.

- Significant heat wave arrives this coming weekend, with minimal
  chance of any thunderstorms for heat relief.

&&

.DISCUSSION /Through Sunday/...
Issued at 204 PM MDT Sun Jul 5 2026

Satellite shows paltry convection over the mountains early this
afternoon, but a bit more instability exists over/south of the
Palmer Divide where isolated to scattered high based storms are
still expected. They will produce gusty outflow winds with DCAPE
already analyzed at 1400-1800 J/kg, so an isolated severe
microburst is possible. To the northeast of Denver, the airmass
is more stable so chances of convection from the northern suburbs
through Greeley and points northeast look minimal.

On Monday, the upper level and thermal ridge over Colorado is
forecast to amplify. This means a couple degrees of warming, with
highs expected to push into the mid to upper 90s across the
plains. There is some mid/upper level moisture moving this way,
and some of this will infiltrate the mountains by late
afternoon/evening as a shortwave lifts northeast from the northern
Great Basin into the northern Rockies. Thus, we`ve ever so
slightly increased PoPs for the late afternoon and early evening,
as a few storms may be able to survive/develop onto the plains
with just a hint of lift/moisture. Like today, these will produce
more gusty winds than any meaningful rainfall.

By late Tuesday, the northern Rockies shortwave is forecast to
have enough influence to help flatten the ridge. This sets the
stage for a few more days of more active weather that could start
late Tuesday and last through Thursday. Tuesday`s convection still
appears relatively high based, but at the same time mid and upper
level moisture will support higher (scattered) shower/storm
coverage. Low level moisture is forecast to return on the plains
and I-25 Corridor which means a couple late day strong/severe
storms would be possible as mid level winds and bulk shear
increase slightly. It appears Wednesday and possibly even into
Thursday would support the greatest risk of severe storms as both
bulk shear and instability increase further, 30-40 kts and
800-1400 J/kg, respectively. Mountain areas should get in on
isolated to scattered showers and storms as well as there will be
greater mid level moisture, but that also means a risk of new fire
starts from lightning as low level moisture will still be
lacking.

The airmass begins to dry from the west late Thursday into Friday,
and humidities will be dropping again. With zonal flow aloft, we
do see breezy conditions in the mountains which leads to at least
elevated fire weather conditions. The plains should be drying
Friday, although some risk of a dryline storm or two on the
eastern plains.

We are still monitoring a heat wave that`s forecast to arrive
next weekend. Ensembles are still in very good agreement that a
dominating ridge of high pressure builds over the Central Rockies
and centers itself over Wyoming and Colorado toward Sunday. 500 mb
heights are still advertised to reach 2+ standardize anomalies,
and >50% chance that 500 mb heights rise to greater than 600
decameters. Right now, the operational runs keep the greatest 850
mb temperature anomalies to our north, at least initially as the
low and mid level thermal ridge stays off to our north and west.
As a result, ensembles did back off ever so slightly on the
initial blast of this heatwave. In any case, we`ll still be
looking at hot temperatures with highs near 100F across the plains
and I-25 Corridor by next weekend. There a high probability
(>70%) that we`ll be reaching Heat Advisory criteria either
Saturday or more likely Sunday. In fact, the heat will likely
build further with 100-105F readings likely (>60% chance) for the
plains and I-25 Corridor through the following Monday and Tuesday,
as long as the thermal ridge shifts across our forecast area.
Record highs will be possible Sunday to Tuesday (Records for
Denver are 102F, 100F, and 101F for those three days, so Monday`s
and Tuesday`s records are well within expectations).

&&

.AVIATION /06Z TAFS through 06Z Tuesday/...
Issued at 1116 PM MDT Sun Jul 5 2026

Southerly winds are in place across the Denver TAF sites late
tonight. Expecting elevated smoke concentrations by sunrise again
this morning, bringing potential for slant-range vis reductions
for a few hours until better mixing occurs. Main concerns for
today will be similar to yesterday, with high-based showers
bringing potential for gusty outflows/microbursts between 21Z-1Z.
Shower coverage does look slightly more than Sunday, with KAPA
having the greatest chances once again.


&&

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

&&

$$

DISCUSSION...20
AVIATION...9

NWS BOU Office Area Forecast Discussion