San Acacio, CO 81151 Weather

This hazardous weather outlook is for portions of central: east central: south central and southeast Colorado.

Day one: This Afternoon and Tonight

A few showers and thunderstorms will be possible over the far southeast plains this afternoon. Any thunderstorms will be capable of producing outflow winds to 45 mph, lightning, and locally heavy rainfall.

Areas of fog will be possible late tonight through early Saturday morning morning over portions of the eastern plains. Fog could become dense at times in some areas, with very limited visibility.

Days two through seven: Saturday through Thursday

Snow and rain will move into the mountains this weekend, increasing across the region into next week. Accumulating snow is expected over the taller mountains, with moderate to heavy rainfall possible over the lower elevations. Flooding potential will increase along the Continental Divide and across the San Luis Valley Sunday and into Monday. Meanwhile, portions of the plains may see a wintry mix through about Tuesday.

Spotter information statement

Weather spotters will not be needed today or tonight.

Key messages

- Scattered showers/storms along the Continental Divide tonight and Saturday morning.

- Incoming system will bring heavy rain and potential flooding to the San Juans Sunday/Sunday night, with runoff into the San Luis Valley on Monday/Tuesday.

- Snow levels drop late Sunday night, with over a foot of heavy, wet snow over the higher elevations of the ern San Juans.

- Showers elsewhere Sunday/Monday with strong winds in excess over 50 mph possible on the plains Monday behind a cold front.

Update

Issued at 340 PM MDT Fri Oct 30 2026

Quick update to the forecast package to include some patchy fog across portions of the eastern plains tonight.

Short term

Issued at 204 PM MDT Fri Oct 30 2026

Initial upper wave approaching the area this afternoon, with some convection firing over nrn AZ and nw NM as of 2 pm. Expect main wave of convection to pass through the area overnight (06z-12z), with a round of quick moving showers (an isolated thunderstorm possible as well), most numerous over the ern San Juans/central mountains, mainly isolated valleys and eastern mountains. QPF doesn't look particularly high, with amounts of under a quarter inch and a snow level around 9500 feet. Could also see a few showers over the far sern plains overnight, as upper low lifts out of TX, though precip here looks very light, only a few hundredths. Showers end fairly quickly Sat morning, with a lull in precip at most locations from the afternoon into Sat night. Once showers clear, Sat ends up being a very nice Autumn day (maxes in the 60s lower elevations, 40s/50s mountains), with just some moderate south winds in the afternoon as surface pressure gradient slowly tightens.

Long term

Issued at 204 PM MDT Fri Oct 30 2026

Main upper trough moves onshore Sunday morning, pushing into the Great Basin by Sunday evening, then across Colorado on Mon. Ahead of the trough, moist sw flow will develop across swrn CO, with rain starting in the ern San Juans shortly after sunrise Sun, becoming heavy from midday into the evening, then changing to snow overnight into Mon morning as colder air aloft under the upper trough moves across and mid-level flow becomes more wly. Model QPF in the San Juans continues to rise, with forecast amounts of over 3 inches of liquid near Wolf Creek Pass by Mon evening. Snow level rises to above 10000 feet by Sun afternoon, before falling back toward 9000 feet early Mon morning, which suggests the threat of several hours of rain on portions of the San Juan snowpack (SWE 1-3 inches below about 11k feet), which will increase the flooding risk. Did issue a Winter storm watch for Sun night into midday Mon for the higher elevation San Juan zone, where over a foot of snow is possible. Elsewhere, lighter showers spread across the higher terrain during the day Sun into Sun night, though precip amounts away from the San Juans will be much lighter, generally less than a half inch. Plains will stay warm and dry again on Sun, with increasing s-sw winds as surface low spins up near Limon.

On Mon, upper trough moves across CO, as upper low lifts out of the ern plains into ern KS by Mon evening. Showers will continue over the mountains through the day, with lowering snow levels at most locations as cold air deepens under the trough. Plains will see wrap-around showers and strong north winds as low departs, with heaviest precip along/south of the Arkansas River where nly upslope component will boost vertical motion. Precip ends Mon night, though north winds will remain gusty on the plains into the first half of the day Tue. Flat upper ridge then returns for most of the week from Tue onward, with warm and dry weather most locations, though next upper trough and precip are already lining up for next weekend.

Aviation

Issued at 539 PM MDT Fri Oct 30 2026

Widespread mid and high level cloudiness expected through the forecast period. VFR conditions through approx 06z tonight, then gradually degrading conditions with lowering clouds, and patchy fog developing across the eastern plains.

KCOS: MVFR conditions 07z-17z, with IFR due to patchy fog and low cigs 10z-15z.

KPUB: VCFG by 07z, then MVFR 10z-17z.

KALS: MVFR conditions between 11z and 16z. Gradual increase in southwest flow Sat morning.

Hydrology

Issued at 124 PM MDT Fri Oct 30 2026

Main concern will be flooding along the South Fork of the Rio Grande and Conejos Rivers, especially Sunday night into Monday morning. May have several hours of heavy rain on snow-pack Sun afternoon in the San Juans, as snow level rises to above 11000 feet for a time Sun afternoon/evening. This could lead to melting and excessive run-off, as QPF over along the Continental Divide has come up to around 3 inches of liquid (some of which will be snow). Run-off peak should be late Sun evening, before snow level falls and run-off starts to decrease early Mon morning. River stage forecasts continue to rise, with the South Fork of the Rio Grande at South Fork and the Conejos River at Mogote well above flood stage by early Mon morning. These high flows will then move downstream Mon/Tue with flooding possible on the mainstem Rio Grande at Del Norte and along the Conejos River east of Mogote through the period. As a result, issued a flood watch for all of the San Luis Valley, from late Sun night into Tue morning, mainly for mountain run-off, as rainfall in the Valley itself should be an inch or less.

Watches, warnings and advisories

Flood Watch from late Saturday night through Monday morning for COZ067-068. Winter Storm Watch from Sunday afternoon through Monday morning for COZ068. Flood Watch from Sunday afternoon through late Tuesday night for COZ069>071.