National Weather Service Forecast Discussion

Thornton Weather Forecast   
Today's Forecast Story   
634
FXUS65 KBOU 220851
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
251 AM MDT Tue Sep 22 2026

.KEY MESSAGES...

- Isolated chances for showers/thunderstorms Tuesday afternoon and
  evening.

- A disturbance moves through Wednesday and Thursday bringing
  increased chances for showers/storms and cooler temperatures
  Thursday.

- Drier and warmer this weekend, but isolated chances for showers
  and thunderstorms in the evening are possible.

&&

.UPDATE...
Issued at 248 AM MDT Tue Sep 22 2026

With a uniform low stratus deck advecting into our northeast
plains, as well as broken stratus over the Palmer Divide, have
introduced a mention of patchy fog into the forecast for the early
morning hours in these areas. Relatively robust drainage flow
should pump the breaks on the status expansion in the plains very
shortly, confining most of the visibility impacts to Logan,
Sedgwick and Phillips Counties. Any fog should be relatively
brief, lifting by mid-morning.

&&

.DISCUSSION /Through Monday/...
Issued at 1208 AM MDT Tue Sep 22 2026

Satellite imagery shows a few patchy low clouds over the eastern
Colorado plains and a quiet night ahead. Lows tonight will be in
the low 50s at low elevations and 30s-40s for the mountains.
Temperatures Tuesday afternoon warm up slightly but remain right
at seasonal averages, with highs in the low 80s for the Denver
metro. A shift to SW flow aloft will result in the return of
monsoonal moisture for the mountains. As such, a few isolated
showers and storms may develop over the high terrain late in the
afternoon. The chance for showers over the Denver metro and east
Colorado plains will remain very low (

NWS BOU Office Area Forecast Discussion