National Weather Service Forecast Discussion

Thornton Weather Forecast   
Today's Forecast Story   
988
FXUS65 KBOU 140702
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
102 AM MDT Fri Aug 14 2026

.KEY MESSAGES...

- Another round of storms this afternoon and evening with a
  continued threat of locally heavy rain.

- Monsoon moisture lasts through the weekend, bringing scattered
  showers and thunderstorms most days.

- Warming and drying trend still set to begin Monday.

&&

.DISCUSSION /Through Thursday/...
Issued at 1245 AM MDT Fri Aug 14 2026

Today`s weather will be similar to yesterday`s. Monsoonal moisture
will continue to stream into the area as the upper level high sits
to our southeast and troughing sits over the West Coast. PWs will
continue to be in the 120% to 200% of normal range today. A weak
disturbance in the flow aloft this afternoon, upslope flow, and
the high PWs will lead to another day of scattered to numerous
storms. Storms are expected to develop in the afternoon in and
around the higher terrain/Foothills, moving east/northeast into
the late evening. Storm motion will be a bit faster this afternoon
compared to yesterday, which will help lower the flash flooding
threat. However, the areas which have received rain over the past
2 days will be more prone to flooding, due to more saturated
soils. Instability and shear will be a bit higher this afternoon
for our eastern plains. This could allow for a few strong to
severe storms, with potential for marginally severe hail and
strong winds. CAMs are less enthusiastic with the rain totals for
today compared to yesterday. This, combined with the faster storm
motions, has caused us to hold off on a Flood Watch for this
afternoon. However, heavy rainfall and localized flash flooding
is still a threat today, especially for areas that received heavy
rainfall Thursday.

Upper level southwest flow will allow the monsoon moisture to remain
in the area through the weekend. This will bring daily rain chances
for our forecast area through Sunday. Instability and shear will
remain high enough for a daily severe weather threat at well.
Strong winds, hail, and heavy rainfall leading to flash flooding
will be possible each afternoon/evening this weekend. It is
important to note, that with the rain chances Friday through
Sunday, not every location in our CWA will receive rain each day.
But, by the end of the weekend many locations will likely see some
rainfall, with potential for that rain to be heavy at times.

Rain chances will decrease for Monday and Tuesday (still a low
chances, but not as high as previous days) as the upper level high
builds to our south and the flow aloft turns more zonal, cutting off
the monsoonal moisture. Temperatures will warm closer to normal or
slightly above normal during this time, with highs around 90
degrees in the urban corridor and plains by Tuesday. There`s quite
a bit of uncertainty beyond Tuesday. Some models and ensemble
members bring a weak front and a decent shortwave on Wednesday,
lowering temperatures and bringing additional rain chances to the
area. While other ensemble members, have a much weaker shortwave
(if anything at all), causing very little change in temperatures
for Wednesday.

&&

.AVIATION /06Z TAFS through 06Z Saturday/...
Issued at 1131 PM MDT Thu Aug 13 2026

The light showers near KDEN and KAPA will continue to move to the
east, moving out of the vicinity soon. Winds will become light and
variable overnight. A stratus deck is trying to form to the north
and east of our TAF sites, with ceilings around 900ft right now at
KFNL. These lower ceilings will likely try to build south
overnight, along with some patchy fog, with the highest chance of
impacting KBJC. The stratus deck is expected to remain FEW to SCT
at KDEN and KAPA, but this could change overnight as we watch it
develop and progress towards these areas. Another round of
thunderstorms is expected tomorrow, with similar timing to
today`s storms. Highest chances for storms will be from 20Z to
24Z, with some lingering activity possible into the late evening.

&&

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

&&

$$

DISCUSSION...AP
AVIATION...AP

NWS BOU Office Area Forecast Discussion