743
FXUS65 KBOU 150002
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
602 PM MDT Mon Sep 14 2026

.KEY MESSAGES...

- Isolated to scattered showers and a couple storms through the
  evening. Mostly light precipitation amounts.

- Unsettled pattern rest of this week, but plenty of uncertainty
  with regard to daily precipitation chances. Thursday still looks
  like the highest opportunity of measurable rain (50-70%), and a
  locally heavy rainfall threat.

- Cooler weather arriving for Tuesday. Temperatures bounce back
  Wednesday, but then average around seasonal normals through next
  weekend.

&&

.DISCUSSION /Through Monday/...
Issued at 251 PM MDT Mon Sep 14 2026

Light showers sprinkled across the area and abundant cloud cover
have allowed temperatures over the Denver metro and plains to linger
in just the low 80s. The mountains have seen a bit more sunshine as
a shortwave continues push east However, daytime heating and
monsoonal moisture have quickly promoted the development of showers
and storms over the peaks and ridges with winds occasionally gusting
to 30-40 mph. Though an isolated shower cannot be ruled out for the
Denver metro late this afternoon, the best chance of rain at low
elevations will be over the easternmost Colorado plains, where
better instability and moisture are in place.

A cold front will move in from the north late tonight, bringing a
period of breezy northerly winds in the early morning hours. High-
res model guidance has trended drier with this cold front, limiting
the development of a persistent stratus layer. However, patchy low
clouds will likely still develop east of Denver and erode just after
sunrise. We expect temperatures on Tuesday to stay below normal,
with highs in the mid 70s at low elevations. Even with precipitable
water (PW) values in the 90th percentile over much of the state, the
post-frontal airmass over the plains will struggle to destabilize
leaving the best chance for showers in the mountains.

A closed upper-level low pressure will begin to slide through the
Pacific Northwest and Great Basin region on Wednesday, turning flow
aloft south-southwesterly. Modest monsoonal moisture transport will
bring PW values as high as 0.80-1.00" to the mountains with higher
values possible for the eastern Colorado plains, where southerly
surface winds may advect additional moisture. Therefore, Thursday
still looks to be the best chance for meaningful rainfall amounts
over the Denver metro. The flash flooding threat appears to be
localized in nature given the very shallow warm-cloud layer and
marginal storm motions (LCL-EL mean winds ~18KT).

The evolution of a few shortwave troughs over the Pacific Northwest
Friday through Sunday remains unclear. However, there will likely be
enough moisture for daily precipitation chances, particularly over
the high terrain. Temperatures will remain near-normal or even
cooler than normal, with highs in the upper 70s and low 80s through
the weekend.

&&

.AVIATION /00Z TAFS through 00Z Wednesday/...
Issued at 540 PM MDT Mon Sep 14 2026

A boundary just moved through KDEN and KAPA, leaving strong
northwest winds in its wake. Winds will gradually weaken over the
next 2 hours, before turning more westerly with speeds around
10kts by 02Z. A cold front will move through the area overnight.
The initial northerly wind shift is forecast between 06Z and 07Z,
with gustier north winds moving in around 09Z for a few hours. By
12Z, patchy low clouds are expected to develop over the TAF
sites. There is potential for MVFR CIGs, around 2000ft, at all 3
TAF sites between 12Z and 17Z, with the best chance for BKN low
clouds between 14Z and 16Z. Winds will turn from a N wind to more
of a E/SE wind by the late morning. We have additional chances for
isolated to scattered showers with gusty winds tomorrow
afternoon, starting between 20Z and 22Z.

&&

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

&&

$$

DISCUSSION...AA
AVIATION...AP

NWS BOU Office Area Forecast Discussion