National Weather Service Forecast Discussion

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473
FXUS65 KBOU 201129
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
529 AM MDT Thu Aug 20 2026

.KEY MESSAGES...

- Warmer and drier conditions expected today, with isolated
  showers/storms in the mountains.

- Slight increase in afternoon showers/storms on Friday, with a
  few capable of producing gusty outflows.

- Monsoon moisture returns this weekend and holds into early next
  week, with increasing chance of storms.

- The urban corridor will continue to see afternoon highs in the
  90s through the weekend, with temperatures climbing into the
  upper 90s on Friday.


&&

.DISCUSSION /Through Wednesday/...
Issued at 128 AM MDT Thu Aug 20 2026

Slightly warmer temperatures are expected today as another upper-
level ridge builds over the Four Corners. Isolated showers and
storms will be possible in the mountains, generally for areas
south of I-70. Widespread highs in the 90s are expected across
the plains, where mostly clear skies and light winds will
prevail.

Friday will be slightly warmer, with afternoon high temps
expected to warm into the mid to upper 90s along the urban
corridor, as the ridge shifts slightly eastward. The current
forecast high at KDEN is 97 degrees, which puts us within two
degrees of tying the daily record high temperature (99F set in
2023) currently in place. Mid-level moisture looks to wrap around
the ridge that will increase enough to see isolated to scattered
high-based showers and storms develop along the higher terrain in
the afternoon, with potential for a few capable of producing
strong to severe gusts if they can manage to make it onto the
lower elevations, as forecast soundings show DCAPE values ranging
from 1200 to 1600 J/kg. Any precipitation that manages to reach
the ground is expected to be very light, with just a few
hundredths of an inch at best.

By Saturday, ensembles show precipitable water values increase
across the forecast area, though the ECMWF is slightly more
bullish than the GFS, with values ranging from 140-180% of normal
compared to 100-160%, respectively. PWATs are expected to remain
elevated through the weekend that will keep decent chances for
showers and storms each afternoon, especially for the mountains.

A shortwave is expected to move along the northern tier Sunday
and Monday that will flatten the ridge for at least a few days,
bringing more zonal flow aloft and a few days of slightly cooler
temperatures, with daily afternoon shower/storm potential
remaining into the start of next week.

&&

.AVIATION /12Z TAFS through 12Z Friday/...
Issued at 525 AM MDT Thu Aug 20 2026

VFR to persist through the TAF period. Light southwesterly winds
are in place at KDEN/KAPA, with light and variable winds at KBJC
early this morning. Winds are expected to begin a clockwise turn
by 15Z this morning before settling into a northeasterly flow by
around 18Z, where they should remain through the afternoon.
Prevailing wind speeds should remain below 10 kts, with a few
gusts between 12-15 kts possible in the afternoon. Winds will
continue their clockwise turning again around 0Z, with drainage
winds expected again for the overnight hours. Any afternoon
showers or storms that develop are expected to remain over the
higher elevations to the southwest of the TAF sites.

&&

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

&&

$$

DISCUSSION...9
AVIATION...9

NWS BOU Office Area Forecast Discussion