903
FXUS65 KBOU 132053
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
253 PM MDT Mon Oct 13 2025

.KEY MESSAGES...

- Scattered rain and snow showers through tonight.

- Mainly dry with above normal temperatures Tuesday and Wednesday.

- Precipitation chances return late Wednesday into Thursday across
  the mountains and plains. Cold enough for snow in the higher
  mountains.

- Turning warmer and drier again by the weekend.

&&

.DISCUSSION /Through Monday/...
Issued at 238 PM MDT Mon Oct 13 2025

A weak shortwave should race across the region this evening into
tonight, with scattered rain showers across the plains and
rain/snow showers over the higher elevations. We should quickly
clear behind the shortwave tomorrow, with warmer temperatures
likely in the continued south-southwesterly flow aloft.

A large upper low is expected to drift from the central California
coast into central Utah from Tuesday afternoon into Wednesday
night, with the upper flow aloft gradually strengthening.
Wednesday looks to be the warmest day of the week - coinciding
with the stronger mid-level flow and warmer 700mb temperatures
(near 10-12C) - with highs likely reaching the mid/upper 70s. A
few spots in the plains may see some low 80s. Despite the
approaching trough, moisture is fairly limited and there shouldn`t
be much more than a few light rain or snow showers across the
higher terrain.

The upper trough axis is then expected to weaken and lift
northeastward into Wyoming from Wednesday night into Friday
morning, with one stronger shortwave rotating around the base of
the trough into our CWA sometime on Thursday. Guidance for the
most part is in agreement that this should provide a brief shot of
snow across the northern mountains, perhaps with some upslope
precipitation across the Front Range behind a cold front. Still,
the limited amount of moisture to work with along with the brief
period of favorable lift will keep any snowfall accumulations
fairly light.

The upper trough should lift well into the northern Great Plains
by this weekend. Northwest flow aloft on Saturday will keep
temperatures near normal, and could also bring some orographic
snow to portions of the northern mountains (mainly Park Range) if
enough moisture lingers in the area. A ridge is expected to build
into the region Sunday and Monday, with a good signal for above
average temperatures.

By early next week, most guidance tries to bring in a strong
shortwave/trough axis into the region, though there are fairly
large differences in timing/strength. Either way, that potential
storm system would bring us back to cooler than normal
temperatures, along with a chance of some rain and snow into the
region.

&&

.AVIATION /18Z TAFS through 18Z Tuesday/...
Issued at 1123 AM MDT Mon Oct 13 2025

Showers have pushed off the Palmer Divide a little ahead of
schedule this morning dropping CIGs to around 7,000 feet.
SSE winds are expected to remain in place through the day at
KDEN/KAPA, with gusts between 20-30 kts expected through the
evening. There is more uncertainty with winds at KBJC, but still
expecting the southerly winds to make their way there once a
little more mixing occurs. With southeasterly winds in place,
there is always the potential for a cyclone to develop across the
plains that could lead to a significant departure from the current
TAF, but this will have to be monitored as the day progresses.

Current showers are expected to be the first of two waves today,
with the second wave coming overnight tonight. As of now,
confidence was not quite high enough to mention in the KDEN TAF
(~20-25% chance), but this may change as the day progresses. Even
if the showers don`t develop overnight tonight, there will at
least be increased moisture and ceilings as low as 4,000 to 5,000
feet are expected through the morning tomorrow. Things should
start to break up by 15-16Z.

Guidance shows a more defined cyclone develop north of the TAF
sites by late tomorrow morning that will make winds tricky to
forecast. By 18Z, guidance shows potential for a shear zone
developing across KDEN/KAPA. This would keep winds southerly on
its southern flank and NNW on its northern flank, but this all
depends on where the cyclone actually forms. Confidence is high
for winds through the morning, but will need to monitor where the
cyclone forms to get a better handle on directions for the
afternoon.

&&

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

&&

$$

DISCUSSION...Hiris
AVIATION...999

NWS BOU Office Area Forecast Discussion