Black Forest, CO Weather

Key Messages

- Isolated to scattered showers and thunderstorms mainly for the Mountains and Baca County this afternoon.

- Very heavy rainfall expected for the Mountain areas, focused on the San Juan Range where 2-4 inches of rain may be possible.

- Dry and continued warm on the Plains through Friday.

- Much uncertainty for the weekend into early next week with little run to run model consistency.

Short Term

Issued at 1232 AM MDT Tue Oct 20 2026

Currently...satellite imagery shows scattered mid to high clouds spread across southern Colorado early this morning. There are a few weak echoes showing up on radar across the higher terrain. A few locations out west may see a few sprinkles through the early morning hours. Temperatures have cooled down into the mid 40s to lower 50s, with a few degrees of further cooling expected through daybreak.

Today and tonight...weak energy moving northward through the southwest flow will continue to produce isolated to scattered showers across the higher terrain through this afternoon. Instability is weak, at only 100-200 j/kg, but may be enough for a couple rumbles of thunder this afternoon. Lightning would be the main concern for any thunderstorms that do occur. There could also be a couple of weak thunderstorms this afternoon across Baca County, with lightning being the main concern. The Baca County storms will quickly move into Kansas by mid to late afternoon. Temperatures this afternoon will remain warm, with 70s across the Plains, and 60s for the San Luis Valley.

Upper level ridging will build across southern Colorado ahead of an approaching storm system for later in the week. This will help dissipate any showers over the mountains, with dry conditions area-wide from this evening, into Wednesday morning. Overnight lows will fall into the 40s for the Plains, and lower 30s for the San Luis Valley.

Long Term

Issued at 1232 AM MDT Tue Oct 20 2026

Models and ensembles continue to be in good agreement through Friday, with disagreement in how they want to handle a secondary system over the weekend into early next week.

Wednesday through Friday...a strong upper level storm system is forecast to move across the region from mid to late week. Deep tropical moisture off the Eastern Pacific will be advected northward into western Colorado, and multiple waves are forecast to lift north in persistent south-southwest flow. PWAT values are still forecast to be high, in excess of 0.8 inches to 1.2 inches across southern Colorado. The latest guidance does print out weak instability for the mountains, with around 200 j/kg CAPE, which will likely aid in heavier rainfall production. Models and ensemble guidance trends have remain consistent for the past 4 cycles, with almost all solutions producing 2 to 4 inches across the San Juan Range during this time frame. The Canadian continues to have the highest QPF amounts, and the average for the San Juan Range is around 3.5 inches. DESI probs still have 90+ percent of 2 or more inches. Confidence remains high that the San Juan Range will see heavy rainfall. Flooding of small streams, and potential mud/land slides will be possible. Elsewhere, moderate rainfall is likely from the Central Mountains, southeast across the San Luis Valley and Eastern Mountains. Rainfall amounts of 0.5 to 1 inches are possible, with the highest amounts along the Continental Divide from the La Garita Range, north into the Central Mountains. The Plains, especially east of I-25, look to miss out on precipitation. Snow levels will be high with this event, with NBM snow level guidance above 13 kft. They really don't fall to below 11 kft until late in the event on Friday morning.

Across the Plains, temperatures will be warm, with 70s to near 80 each afternoon, and dry conditions will prevail, especially east of I-25. The main concern will be winds Thursday and Friday. As the upper storm system lifts out of Utah and into Wyoming, strong southwest winds will spread across the Plains. Gusts on Thursday look to range 30 to 35 mph, increasing on Friday to 40 to 45 mph, especially out near the Kansas border.

Saturday into Tuesday...uncertainty exists over the weekend into early next week with the evolution of the upper pattern. The latest 00z GFS and ECMWF develop a secondary upper low over the Desert Southwest, drawing moisture northward across eastern Colorado. Meanwhile a cold front from the passing upper system will back across the Plains turning upslope. Both solutions have abundant precipitation spreading across the Plains in moist southerly flow aloft. Overall, there has been little run to run consistency with this solution, and if ensemble guidance and the GFS/ECMWF continue to show this, pops will likely need to be increased over the weekend into early next week (the ECMWF is slow to lift the system out). Temperatures have been consistently cooler, with 50s and 60s across the Plains.

Given the uncertainty over the weekend, next Monday and Tuesday are a very low confidence forecast at this time.

Aviation

Issued at 529 AM MDT Tue Oct 20 2026

KALS: Passing showers and MVFR cigs will be possible through about 15Z. After that, clouds should waver between MVFR and VFR, with southwest winds through the rest of today. Overnight, lighter winds and VFR returns.

KCOS and KPUB: VFR is expected through 24 hours. Winds will generally follow diurnal flow patterns and remain under 12 knots, with persistent mid-level clouds. There may be a shower or two over the mountains near KCOS this afternoon, though currently no impacts are expected at the terminal.