469
FXUS65 KBOU 301134
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
534 AM MDT Wed Sep 30 2026

.KEY MESSAGES...

- Rain spreads northward today, with the highest rain chances and
  heaviest amounts to the south and southeast of the Denver area.

- Little to no rain for the northern urban corridor and northeast
  plains.

- Flood Watch in effect for southern Lincoln and far southeastern
  Elbert counties through Thursday morning.

- Rain ends Thursday morning over eastern Colorado.

- Warmer and drier for the weekend and early next week.

&&

.DISCUSSION /Through Tuesday/...
Issued at 1139 PM MDT Tue Sep 29 2026

Looking at satellite late this evening, the upper level low is
currently moving out of southern California and into Arizona with
widely scattered showers and storms ahead of the trough to our
south. The showers and storms will gradually move north/northeast
as the surface low tracks northeast. Light showers are starting
to approach southern Lincoln County as of late this evening. Rain
chances will increase for the Palmer Divide area late overnight
through early Wednesday morning and the urban corridor by the
late morning to early afternoon. Models have continued to trend
lower for rain amounts in our area, due to a more southern track
of the upper low and eastward track of the surface low. With the
surface low being a bit more east, it`s much harder to get the
higher moisture to wrap around into our area. We will have enough
moisture for some lighter rain activity and we are still expecting
rain on Wednesday for many areas south of I-76, but forecast
amounts have decreased and the risk for flooding has decreased.

The best chance for higher rain amounts in our area will be in our
southern most counties (Lincoln and potentially the Palmer Divide),
but the highest rain amounts for this system are expected to
remain to the southeast of our forecast area. We`ve left the
Flood Watch for the southeastern Elbert and southern Lincoln
County zone, but there`s still uncertainty on if the heavier
rainfall will even make it that far north. Short of some unlikely
mesoscale feature setting up, like an MCV, we`re looking at much
lower rain totals for our area than previously forecast. Overall
for our forecast area, expect more of a steady light rain event
for areas south of I-76 tomorrow, with a slight chance for one or
two areas to see higher amounts approaching one to two inches.

This system is forecast to move off to the east late Thursday, with
upper level ridging building in behind it. The ridging should
hold through the weekend, bringing warmer and drier conditions.
Highs are forecast to be above normal Friday through Monday, with
highs approaching the low to mid 80s for portions of the plains by
Monday. Our next chance for rain could accompany an upper level
shortwave late Monday into Tuesday, but rain chances remain low
(<30%) for now.

&&

.AVIATION /12Z TAFS through 12Z Thursday/...
Issued at 534 AM MDT Wed Sep 30 2026

There is still a good amount of uncertainty regarding ceiling
heights and rainfall placement for the upcoming system today. It
appearsDEN and BJC will be on the edge of the lower clouds
(3,0006,000 ft) and rain. Best chance for the lower clouds at DEN
and BJC will be 16-23Z. After 00Z, drier air moves in, but model
cross sections still hold onto a sct-bkn layer around 6000-8000
feet. At APA, rain and lower clouds are expected to move in
between 14Z and 15Z and linger through most of the afternoon.
Improving conditions are expected by 00Z Thursday as well. Light
north to northwest winds will increase this morning and be north
to northeast most of today before becoming light and variable
around 00Z Thursday.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Thursday morning for COZ047.

&&

$$

DISCUSSION...AP
AVIATION...BM