Key messages
- High potential for a widespread hard freeze ending the growing season across the southeast plains tonight through Saturday morning
- Warming into the weekend with a weak system bringing some mountain showers Sunday and Monday
- Next system will bring increasing winds by mid week and the potential for rain and mountain snows sometime late week or next weekend
Short Term /Through Tonight/
Issued at 1234 AM MDT Fri Oct 16 2026
Reinforcing surge of cold dry air will descend through the plains overnight behind a trailing upper trough dropping through the northern and central high plains towards the upper Midwest. Winds will remain elevated across the plains overnight/early this morning as a reinforcing high pressure moves through the region, but it will also bring drier air under a mostly clear skies. Best chance for a hard freeze this morning still looks like Northern El Paso County where probabilities are around 50 percent. Kiowa and southern El Paso county have a 30-50 percent chance of seeing freezing temperatures though readings may not be quite cold enough for long enough to qualify for a growing season ending hard freeze. For the counties along and south of highway 50, odds are less likely as winds may keep the lower levels mixed, but some patchy frost with a brief dip to near freezing as winds decrease towards dawn will be possible early this morning and Frost Advisories still look on target. Across the San Luis Valley where some locations didn't quite make the 3 hours of 28 degrees or colder necessary for a growing season ending hard freeze yesterday, tonight will likely do it under clear skies and falling surface dew points.
Otherwise, today will remain cool but sunny with temperatures similar to a degree or two cooler across the plains. The mountains will start to see a slow warm up as ridging aloft moves in out west. Winds will be relatively light, especially towards afternoon as the surface pressure gradient relaxes across the eastern plains.
Another clear cold night expected with another round of freeze warnings likely. Winds will be lighter and the airmass drier, however there will also be a developing lee trough along the lee of the mountains which could kick up some westerly winds towards morning west of I-25 which could offset the potential cooling and freeze potential. Will maintain current set of Freeze Watches for now to let current round of Frost and Freeze highlights play out. It is possible that eastern Fremont and Huerfano counties could stay too mixed for a hard freeze tonight depending on the timing of the lee trough development. Will let later shifts and another suite of model runs come in before making upgrade decisions, but probability is high for an upgrade to Freeze Warnings for locations along and east of I-25. -KT
Long Term /Saturday Through Thursday/
Issued at 1234 AM MDT Fri Oct 16 2026
Warmer conditions return over the weekend with ridging aloft transitioning to southwest flow ahead of a filling upper low entering southern CA and western AZ on Sunday. Saturday remains dry across southern CO but some moisture advects in for Sunday and Monday as this weakening upper level disturbance gradually lifts out across CO. Some isolated showers will be possible, mainly for the mountain areas with some spotty light rainfall possible. Snow levels will remain above 10000 feet during the day time hours when showers will be most prevalent.
The next upper trough moves into the west coast Tuesday and Wednesday. This will increase southwest flow over CO bringing breezy and warm conditions with increasing showers across the Continental Divide. Best chances for showers will be across the eastern San Juans due to orographically favored southwest flow, however this will be warm system with snow levels remaining high.
Upper low will translate through the western U.S. towards CO into late week, though details on timing, track and strength are highly variable at this point. Trend will be towards unsettled weather and a cool down perhaps next weekend as the system crosses the Rockies. -KT
Aviation /06Z Tafs Through 06Z Saturday/
Issued at 1049 PM MDT Thu Oct 15 2026
VFR conditions at all taf sites the next 24 hrs. Very low risk (10 percent) of some patchy ground fog along the Arkansas River/Rio Grande toward sunrise as surface dewpoints are only slowly falling, but won't include in the tafs at this point as drier air aloft will likely prevent formation. Mainly light diurnal winds under 12 kts at all terminals the next 24 hrs, with a brief period of gusty (g15-20 kts) north winds possible at KCOS 09z-14z.
Pub Watches/Warnings/Advisories
Freeze Warning until 9 AM MDT this morning for COZ069>071-084- 085-095-096. Frost Advisory until 9 AM MDT this morning for COZ083-086>089- 093-094-097>099. Freeze Watch from late tonight through Saturday morning for COZ083>089-093>099.
SHORT TERM...KT LONG TERM...KT AVIATION...PETERSEN