Brush, CO Weather

Key messages

- Areas of dense fog across portions of the plains overnight through mid morning Friday. This fog will impact the morning commute from Denver north to the Wyoming border

- Mild and mostly dry through the work week.

- Unsettled weather returns late this weekend and early next week. Mountain snow is likely (>70% chance) above 8500ft during this time. High uncertainty remains for the foothills and plains.

.DISCUSSION /Through Thursday/: Issued at 1026 PM MDT Thu Oct 29 2026

For late tonight thru Fri morning main concern is how widespread dense fog may become along portions of the I-25 Corridor from Denver north to the Wyoming border and points eastward. HRRR has been consistent in showing fog developing over ern Larimer and Weld county by midnight and then spreading it southward into nrn portions of the Denver area by 3 am or 4 am. This fog would then linger thru the mid morning hours on Fri before lifting. In addition, soundings show some potential for drizzle as well.

Meanwhile, for the rest of Fri, the flow aloft will be SW with only isold showers possible in the mtns and far nern plains in the aftn. As for highs, readings will be in the lower to mid 60's across the plains, however, lingering low clouds could keep temps in the 50's over the far nern plains.

For Sat, little change is expected as SW flow aloft remains over the area. There still appears to be a weak disturbance embedded in the flow which may bring a chc of showers to portions of the higher terrain with an isold shower threat across the plains. Temperatures will remain in the upper 50's to mid 60's over nern CO.

Looking ahead to Sun and Sun night, there continues to be some uncertainty as to how an upper level trough along the West Coast evolves. The ECMWF and GFS now have a disorganized elongated upper level trough moving into the nrn Rockies and Great Basin by Sun night. Ahead of this feature, there will be quite a bit of subtropical moisture affecting the higher terrain, especially by Sun night. As a result, should see an increasing chc of showers over the higher terrain with snow levels dropping below 10000 ft late Sun night. Across the plains, it looks dry and windy thru Sun aftn as sfc low pres intensifies from ern WY into ern CO. By Sun night, latest data shows varying precip chances across the plains. For now, have kept in a chc of showers as a band of mid level QG ascent moves across overnight.

On Mon, the ECMWF and GFS have two main areas of energy associated with the elongated upper level trough. One piece stays over the nrn Rockies while a 2nd piece of energy moves across srn CO/nrn NM. If this occurs best chc of decent precip would stay mainly to the north and south of the area. Meanwhile, both models shows a stg cold front moving across the plains with gusty north winds behind it.

For Mon night into Tue, the ECMWF and GFS keep the two pieces of energy separated as the one piece over the nrn Rockies moves SSE across Colorado while the other piece of energy moves from nern NM into central Oklahoma. In addition, the GFS intensifies the upper level low as it moves into Oklahoma by late Mon night. The ECMWF has very little additional precip Mon night into Tue as much drier air spreads across the area. Meanwhile, the GFS has a band of precip over the ern plains Mon night but also decreases the chc of precip over the area on Tue. Winds will remain gusty over the plains Mon night into early Tue as well.

By Wed an upper level ridge will build over the area ahead of another possible system moving across on Thu. For now, Wed looks dry and warmer ahead of the next system.

.AVIATION /06Z TAFS through 06Z Saturday/: Issued at 1139 PM MDT Thu Oct 29 2026

Main concern for the TAF period continues to be the potential for FG and LIFR conditions at DEN/BJC through mid-morning Friday.

There's been a gradual increase in fog and stratus in northern/northeastern Colorado over the past few hours, though it's difficult to determine the extent given the expansive high cloud cover across the region. A weak surface cyclone exists, centered roughly between DEN and FMM at this time. Surface dew point depressions are still fairly large (6F at DEN but >10F at LMO/BDU/BJC/CFO) to the west and southwest of the cyclone. Cooler/moist air is evident in the northern I-25 corridor but it should take a few hours until it pushes towards the terminals.

Most near term guidance is still insistent that lower visby should arrive by ~10z tonight, with the best chance of LIFR FG between 11-15z. It looks unlikely that any fog or mist would make it to APA, and it's possible the edge of the fog bank sits just to the north of BJC/DEN. We'll continue to monitor trends overnight.

Any fog should quickly start to dissipate after 15z Friday morning, with light east/northeasterly winds developing. Various amounts of mid/high cloud cover should persist through the day into Friday night, but VFR conditions are anticipated. There is a slight chance of more fog Friday night into Saturday morning, but I would like to see how the early morning fog evolves before introducing anything at the end of the current TAF period.

Watches, warnings and advisories

Dense Fog Advisory until 10 AM MDT Friday for COZ038-042-043.

Dense Fog Advisory from 3 AM to 10 AM MDT Friday for COZ039-040- 044.

Dense Fog Advisory until 8 AM MDT Friday for COZ046-047.