Marine Weather and Tide Forecast for Sheridan, CO

DISCUSSION /Through Saturday/
Issued at 1146 AM MDT Sat Apr 18 2026

The rest of today will see plenty of sunshine and warming temperatures, with highs in the 50s across the plains and 40s in the mountain valleys. Northwest winds are gusting over 30 mph across the northeast plains right now and should continue that way until 6-7 PM. RH at midday is around 20-25% but with additional heating and downslope, they should bottom out around 15%. Thus, the Red Flag Warning will remain in place this afternoon.

Tonight, winds decouple and drier air moves in, but also some warming aloft moves in. Between drainage winds and warmer air aloft, low temperatures tonight should remain above freezing for much of the plains and I-25 corridor. The exception will be the South Platte Valley north of Denver all the way to Nebraska, and the lowlands near and southeast of Limon. In the river valleys they will fall into the low to mid 20s, but given how hard it froze early this morning, there is no need for another Freeze/Frost highlight. The mountain valleys will be seasonably cold in the teens to low 20s.

Sunday through Tuesday will see a warming trend as the 500 mb ridge builds and remains overhead. Temperatures across the plains will warm from the 70s on Sunday to the 80s Monday and Tuesday. The mountain valleys will also warm from the 50s on Sunday to the 60s Monday and Tuesday. Even though a few members of GEFS from prior model runs had a little mountain snow late Monday into Tuesday, the 12Z run does not, and the official forecast is free of PoP as well.
Though it will be warm and very dry, winds should remain light enough through Tuesday to keep elevated fire wx conditions at bay until Wednesday.

On Wednesday the strong trough off the West Coast U.S. comes on shore. Southwest flow aloft over Colorado will increase significantly while simultaneously pushing the ridge off to the east. 700 mb temps should be between +10 - +13 degC with the coolest temps across the North Park. Regardless, that's really warm, and with WSW flow increasing at and below 700 mb resulting in downslope warming, it will be very warm and windy at the surface across the entire area. Expect highs in the 80s across the plains and even upper 80s near the KS/NE border. The mountains will also be quite warm with highs in the 60s in the mountain valleys all the way to at least 9,500 ft elevation. Combined with sustained southwest winds 20-30 mph and RH dipping below 10 percent, pretty much all of the plains are likely to see critical fire weather conditions. The eastern foothills and South Park will also be dry/windy enough for critical fire weather conditions. It will almost definitely be dry across the plains throughout Wednesday, though some ensemble output is hinting that could be some moisture in the southwest flow for light snow across the central mountains, where roughly 1/3 of the EC members, 3/4 of the GFS, and 1/2 of the Canadian ensemble solutions have light snow as soon as midday Wednesday. For now 10-20% PoPs across the highest terrain look appropriate this far out.

Model uncertainty is high Thursday, Friday and beyond as the short wave trough quickly moves east and a long wave trough develop upstream and to the north of us. All models show a pretty deep trough extending from N NM all the way to Canada, with potential for a fair amount of synoptic lift across Colorado as the trough axis moves across the state later next week. Ensemble data suggest a high (> 50%) chance of measurable precipitation across the area sometime in that window. In terms of potential for significant precipitation, here are probabilities of exceeding a quarter inch for the I-25 urban corridor: GEFS 25%, ENS and GEPS 33%. It's a little less than that across the northeast plains.
For the Front Range Mountains looking at exceeding 0.50" liquid: GEFS 25%, ENS and GEPS 33%. It's a long ways out yet and much is likely to change between now and then. Finally, working a little DESI magic to find the joint probability of wet bulb below 34 degF and measurable precip (e.g. probability of snow), shows that unless it's overnight, p-type is likely to be rain if/when it precipitates, and for the overnight hours from Thursday through Saturday the joint probabilities max out around 20-30% for snow at any one time.

AVIATION /18Z TAFS through 18Z Sunday/
Issued at 1146 AM MDT Sat Apr 18 2026

Models show fairly normal diurnal wind patterns for DIA through the TAF period, with light northeasterly winds this afternoon and south- southwesterly winds tonight. There will be no ceiling issues.

BOU WATCHES/WARNINGS/ADVISORIES
Red Flag Warning until 7 PM MDT this evening for COZ242-244- 248>251.