733
FXUS65 KPUB 181819
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
1219 PM MDT Fri Sep 18 2026

.KEY MESSAGES...

- Showers and storms again today, with pockets of heavy rainfall
  possible.

- Thunderstorm chances increase over the plains this weekend as
  the mountains dry out. Strong to severe storms possible late
  Sunday.

- Cooler and wetter conditions set in next week.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 108 AM MDT Fri Sep 18 2026

The monsoon plume remains directly overhead for another day as SE
Colorado remains between an upper low to the NW and a broad upper
high to the SE. Flow aloft will remain out of the southwest, giving
us another day of widespread showers and thunderstorms. Similar to
yesterday, the best moisture remains over the Continental Divide,
while only isolated to scattered showers are expected anywhere east
of the mountains. Despite the abundant moisture out west, the plains
will see much drier conditions at low-levels. As such, any showers
that make it further east will mostly produce brief periods of
rainfall and gusty outflow winds. Meanwhile, the mountains will see
another day with pockets of heavy rainfall. The burn scars will need
to be watched for flash flooding concerns. Later on in the evening,
a cold front will make its way south over the plains, increasing
precip coverage over the Palmer Divide. If a stronger storm is going
to form east of the mountains, it would likely occur along the
front, though even then only expecting the low-end chance for
heavier rain and some small hail. Activity then pushes east and
dissipates overnight, with overnight lows in the 50s to low-60s out
east, and 30s-40s over the high valleys.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 108 AM MDT Fri Sep 18 2026

On Saturday, upper trough deepens just to our west, as a mass of dry
air moves into the mountains. The incoming trough will allow for
some synoptic forcing, meaning that convection won`t turn off
completely, but the influx of dry air will greatly limit the extent
and strength of storms compared to the previous several days. Some
convection will still be present over the Continental Divide in the
afternoon, while most of the plains remain dry. The exception to
this will be late Saturday afternoon into evening, as another cold
front moves in from the north, carrying enough low-level instability
and moisture to allow for some brief showers and storms. These
storms will hit the Palmer First, spreading south and east into
Saturday Night. High temperatures will be similar to those on
Friday, though a few degrees cooler out east thanks to the front.

Sunday will see more dry air working into the mountains, reducing
potential convection to near-zero. Meanwhile, lingering showers in
the morning will potentially limit instability for afternoon
convection out east. That being said, low-level moisture will hang
around, with upsloping post-frontal winds over most of the eastern
plains into the afternoon hours. Some isolated to scattered storms
are expected to form over the Palmer Divide and, if they can last
long enough to move east, they will encounter better air and
intensify. Looking at convective parameters, models do show CAPE
above 1000-1200 J/kg in the afternoon, with around 30-35 knots of
shear depending on which model you go with. As such, any longer-
lasting storms will have the potential to become stronger to low-end
severe, lasting into Sunday Night. Meanwhile, temperatures will
continue their cooling trend, with 70s to low-80s over most of our
forecast area.

Confidence in the model solutions drops quickly as we look into next
week. The general consensus is for a broad upper low to move onto
the CA coast, pushing east towards midweek. This will bring more
Pacific moisture back to our region, along with generally cooler
temperatures. Other than better chances for more widespread
precipitation, we will have to wait until models are in better
agreement with the evolution of the system for more specific
impacts.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1137 AM MDT Fri Sep 18 2026

At KPUB and KCOS, VFR the next 24 hrs, with a prob30 for -tsra
at both sites (best chance at KCOS) from mid-afternoon into
early evening. Main storm threat will be gusty winds and brief
heavy rainfall. Weak cold front will pass through the area
mid/late evening, with briefly gusty north winds behind the
boundary until around 06z.

At KALS, VFR this afternoon and evening, with a prob30 for -tsra
from mid-afternoon into early evening. Storm threat then ends
toward sunset with mid/high level cloud deck overnight. Did
include a tempo for fog/stratus 10z-14z as winds become light
and low levels saturate.

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SHORT TERM...GARBEROGLIO
LONG TERM...GARBEROGLIO
AVIATION...PETERSEN