Key messages
- Drier conditions and below seasonable temperatures are expected Friday through the weekend.
- Sub-freezing nighttime temperatures are forecast across northwest Colorado and other mountain valley areas tonight and Friday night. Freeze Warnings are in effect for those time periods.
- Unsettled weather returns mid to late next week with potential for mountain snow and valley rain.
Discussion
Issued at 1047 PM MDT Thu Oct 15 2026
FREEZE POTENTIAL:
As the trough moves further east over the Midwest, high pressure builds behind over the Great Basin and Intermountain West forming a Rex Block heading into Friday with northerly flow over the region. Much colder air mass settles over the region tonight with lows in the 20s for the northwest Colorado valleys (Yampa River Basin) where a widespread hard freeze appears likely. Other areas in a Freeze Warning tonight include the upper Colorado River valley (COZ008) from Glenwood to Avon and the San Juan River Basin (COZ023). A Freeze Warning remains in effect for those same areas Friday night as well, so depending on how widespread of a hard freeze occurs in these zones would determine whether additional freeze warnings are needed. Outside of these areas, temperatures will be cooler but not expecting temperatures below freezing for the overnight.
DRY THIS WEEKEND:
High pressure moves overhead by Saturday as the Rex Block breaks down and the low that was at the bottom of the Rex Block will open up and pull enough moisture with it to bring isolated showers to the San Juans as it tracks over the Four Corners Sunday afternoon. This is fairly weak so not expecting much impact but drier conditions overall this weekend with temperatures around 5 degrees or so below seasonable. Isolated showers are possible again over the high terrain Monday afternoon as southwest flow keeps the area a bit unsettled. Temperatures overall will bump up a little bit towards normal but lean on the side of below seasonable for most areas.
UNSETTLED WEATHER RETURNS MID TO LATE NEXT WEEK:
The next chance for impactful weather comes mid to late next week beginning Tuesday as a low pressure system dives down the west coast and forms a deep closed low over the Desert Southwest. Diffluent southwest flow will allow for better orographic showers Tuesday, more scattered over the high terrain. This low will track across the Great Basin and lift across the area, currently timed late Wednesday through Friday of next week with cooler conditions returning and better chances of more widespread precipitation and mountain snow. Details are still a bit uncertain with timing, amounts and how much cold air will arrive with this system but this mid to late next week system is one to keep an eye on.
Aviation /12Z Tafs Through 12Z Saturday/
Issued at 504 AM MDT Fri Oct 16 2026
Clear skies and light winds will keep VFR conditions solidly in place over the next 24 hours.
Gjt Watches/Warnings/Advisories
CO...Freeze Warning until 10 AM MDT this morning for COZ001-002-005- 008-023. Freeze Warning from midnight tonight to 10 AM MDT Saturday for COZ001-002-005-008-023. UT...None.
DISCUSSION...MDA AVIATION...TGJT