Shawnee, Colorado Weather Forecast Discussion

917
FXUS65 KBOU 080508
AFDBOU
Area Forecast Discussion
National Weather Service Denver/Boulder CO
1108 PM MDT Sun Sep 7 2025
.KEY MESSAGES...
- Showers and lingering storms over the northeast plains slow to
  exit, but will do so overnight.
- High based isolated showers/storms Monday. Very little to no
  rainfall, but gusty winds of 40-50 mph possible.
- Better chances for showers/storms (and rainfall) mid to late
  next week.
&&
.DISCUSSION /Through Sunday/...
Issued at 207 PM MDT Sun Sep 7 2025
Scattered showers and thunderstorms will continue to track
eastward across the area. Brief moderate to heavy rain and winds
to 40 mph will be possible with most of this activity. Across far
eastern Colorado, better moisture and instability will reside east
of a surface trough and may lead to a couple strong to briefly
severe thunderstorms through the early evening hours.
Upper level ridging slides east over Colorado for Monday. This
will bring warmer and slightly drier air with it. Models in good
agreement showing very little rainfall, but the hi-res models show
high-based showers and a few weak storms Monday afternoon. So we
likely see isolated showers/storms with very little to no rainfall
and gusty outflow winds of 40-50 mph. Temperatures trend warmer
as well with highs in the mid to upper 80s over northeast
Colorado.
The ridge slowly slides east of the state Tuesday with southwest
flow aloft prevailing behind through Thursday and beyond. This
will keep temperatures above normal with highs in the mid to upper
80s over northeast Colorado. Would not be surprised if we end up
seeing a few low 90s as well. Precipitable water values are
slightly above normal ranging from 0.75 (in) to one inch over the
plains. Enough moisture for isolated/scattered showers and
thunderstorms. There is an uptick in moisture for Thursday along
with a shortwave trough. This is expected to lead to better
chances for showers and thunderstorms.
For Friday and next weekend, the upper level ridge off to the
east amplifies and stretches into the Great Lakes and possibly
into Canada. This will start to block the flow aloft to the west
across western North America. Models generally show some sort of
an upper level longwave trough or closed low over western Canada
and the northwest part of the country. A lot of uncertainty what
the main pattern will look like. Colorado should be at the base of
whatever trough/low that forms off to the northwest. This is
expected to keep temperatures at or above normal. Precipitation
chances will depend on the amount of moisture that is able make it
into the region. Southwest flow aloft could transport desert air
into the area, so will generally keep PoPs in the 10-30 percent
range at this time.
&&
.AVIATION /06Z TAFS through 06Z Tuesday/...
Issued at 1108 PM MDT Sun Sep 7 2025
A decreasing outflow from lingering storms over northeast Colorado
could turn the winds a bit more south/southeast through 06Z before
returning to southwest flow overnight. KBJC will remain a little
stronger with a more westerly wind direction.
On Monday, expect a transition from SW-W-NW 12Z-17Z and then more
northerly thereafter. While the airmass will be drier, there will
likely be just enough moisture and strong daytime heating for
isolated high based showers/sprinkles with gusty outflow winds.
The threat of thunder is less than 15%. Thus, we`ll go with PROB30
for light showers and gusty winds to 35 kts in the most likely
time frame of 21/22Z-02Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Meier
AVIATION...Barjenbruch

NWS BOU Office Area Forecast Discussion