textproduct: Pueblo

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 /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 540 AM MDT Fri Sep 18 2026

KCOS, KPUB, and KALS: VFR conditions are expected over the next 24 hours. Winds are expected to remain relatively light, around and less than 10 knots, through this TAF period. With that said though, there may be a brief window early this evening for KCOS and KPUB where outflow away from thunderstorms increases winds out of the north. Along with that, showers and storms are expected to develop this afternoon, which may impact any of the three TAF sites. Main hazards from any thunderstorms will be brief periods of heavy rain, lowered visibility, gusty outflow winds to around 30 knots, and lightning. Otherwise, mid to high level clouds will be in place through much of this TAF period, though with lifting and thinning of clouds tonight into Saturday morning. Given the clearing and lighter winds, fog may develop within the San Luis Valley and may impact the KALS TAF site, significantly reducing visibility to IFR to LIFR conditions.

PUB WATCHES/WARNINGS/ADVISORIES

None.