textproduct: Pueblo

KEY MESSAGES

- High impact heavy precipitation/flooding event still on track for the eastern San Juans and portions of the San Luis Valley Sun/Mon, with flooding along the mainstem Rio Grande possible Mon-Wed.

- Showers and isolated thunderstorms elsewhere over the mountains/valleys (snow higher peaks) Sun/Mon, with windy conditions and showers over the plains on Mon/Mon evening.

- Drier Tue, then a weak weather system will bring back a chance for showers to the region Wed/Thu.

SHORT TERM /THROUGH SUNDAY NIGHT/

Issued at 100 PM MDT Sat Oct 31 2026

Quiet today across the region as initial s/w trough has moved through, though satellite images show large area of Pacific moisture poised to move onshore tonight as West Coast upper trough begins to move eastward. Precip will reach the Continental Divide after midnight as sw flow deepens, with steadier/heavier activity developing by sunrise on Sun as upward motion increases. Could see some snow briefly mix in down to 10k feet or so early in the morning, before snow level begins to climb toward 12k by midday as warm/moist Pacific air mass spreads in. Heavy rain then continues over the San Juans through the day on Sun, with lighter spillover showers into the San Luis Valley/Sangres/central mountains during the afternoon. Forecast QPF for Wolf Creek Pass for the 12hr period of 12z Sun through 00z Mon is over 2 inches, with 1-2 inches forecast farther south over the headwaters of the Conejos River. This rainfall, along with some melting of the snowpack above 10k feet, will likely cause widespread flooding, especially along the Conejos River and the South Fork of the Rio Grande.

Sunday night, first piece of energy ejects from the upper trough, spreading at least some weakening showers and isolated thunderstorms eastward out of the mountains and into the plains, while steadier/heavier precip continues along the Continental Divide. Snow level finally begins to fall toward 10k feet around midnight over the San Juans, then a quicker fall to below 9k feet is forecast by 12z, as upper trough and colder air finally move overhead. Another 1 to 2 inches of liquid is forecast from 00z Mon through 12z Mon, though a portion of this will fall as snow as temps cool.

Overall, previous forecast was in good shape, main changes were to increase QPF slightly, start snow in the San Juans a few hours later, and to decrease snow amounts given later start to snowfall. Upgraded winter storm watch to a warning for the San Juans, as once precip switches, could get a quick foot or more from Wolf Creek Pass up through the higher peaks. Also added pops to the plains Sun night, as precip moves off the mountains, and a few thunderstorms develop along the surface trough over sern CO.

LONG TERM /MONDAY THROUGH FRIDAY/

Issued at 100 PM MDT Sat Oct 31 2026

On Monday, upper trough ejects eastward across CO, with precip tapering off over the southwest mountains through the day as flow becomes more w-nw, while showers linger elsewhere over the remaining mountains and valleys. Strong cold front will swing through the plains early Mon as surface/mid level low moves into KS, with strong north winds and a period of showers and thunderstorms likely along and east of I-25 as vertical motion increases under the deformation band. Will have to watch for a burst of heavier precip (rain and snow) along the east slopes/Palmer Divide/Raton Mesa Mon afternoon/evening, especially if surface winds can take on a a slightly more nely component. Wind gusts could get close to 60 mph on the plains as low wraps up, and will have to monitor areas near the KS border for a potential wind highlight if model trends continue. Precip then ends Mon evening, with a dry day on Tue as upper ridge briefly returns to the area.

Still some uncertainty concerning the mid/late week forecast, as model solutions now show weak energy sliding through the Rockies Wed/Thu, generating a few showers/mtn snow showers across the region through the period. Not expecting heavy precip as system will be rather moisture-starved, though some light snow accumulations over the higher mountains look possible. Solutions regarding the position and timing of the next major upper trough for late week into the weekend still vary widely, though an eastward shift in the trough position has been noted in the overall model/ensemble data, which could limit impacts to srn CO.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1200 PM MDT Sat Oct 31 2026

At KALS, VFR conditions expected for the remainder of today and much of tonight, with lowering VFR cigs by 11z Sun morning. Showers become more widespread after 15z Sun, with MVFR conditions developing and likely to continue for much of the day.

At KCOS and KPUB, VFR today and this evening, then IFR cigs return after 08z as low level winds turn back weak easterly. Haven't hit fog/low visibility too hard yet with still a few degf of t/td spread at the surface, though won't be too surprised if vis drops lower than forecast after 12z as winds turn more sely, especially at KCOS.

HYDROLOGY

Issued at 100 PM MDT Sat Oct 31 2026

Main concern continues to be flooding along the Conejos River and the South Fork of the Rio Grande, especially Sunday night into Monday morning. Models today have come in slightly wetter and warmer with incoming Pacific weather system, and a prolonged period of rain on snow looks likely in the San Juans well into Sunday evening. Snow level rises to above 11000 feet during the day Sunday, and only slowly falls to around 10000 feet Sunday evening, then below 9000 feet by Monday Morning. QPF over/along the Continental Divide has come up to between 3-4 inches of liquid (some of which will be snow) which will be sufficient to cause flooding even without the additional potential runoff from melting snow. Runoff peak should be late Sun evening, before snow level falls and run-off starts to decrease early Mon morning. River stage forecasts continue to indicate significant flooding, with the South Fork of the Rio Grande at South Fork and the Conejos River at Mogote rising well above flood stage Sunday evening, cresting overnight into early Monday morning. These high flows will then move downstream Mon/Tue/Wed with flooding possible on the mainstem Rio Grande at Del Norte/Monte Vista and Alamosa and along the Conejos River east of Mogote through the period. Flood watch remains in effect for all of the San Luis Valley from late Sun night into Tue morning, mainly for mountain runoff, as rainfall in the Valley itself should be between .5 and 1.5 inches.

PUB WATCHES/WARNINGS/ADVISORIES

Flood Watch from late tonight through Monday morning for COZ067-068. Winter Storm Warning from 5 PM Sunday to 11 AM MDT Monday for COZ068. Flood Watch from Sunday afternoon through late Tuesday night for COZ069>071.