Marine Weather and Tide Forecast for Holly Hills, CO

SHORT TERM /Through Saturday/
Issued at 101 PM MST Fri Dec 12 2025

Northwest flow aloft will continue through this weekend with an upper level high off to the west where mild and dry conditions will prevail. A polar low will be centered over the Great Lakes bringing arctic air to the north central and northeast part of the country. This arctic isn't far away from Colorado with temperatures in the teens and lower 20s over northwest Nebraska and northeast Wyoming.

For tonight, surface pressure lowers along the base of the foothills. Expect downslope winds to increase in the Front Range Mountains and foothills. Typical windy locations are expected to see gusts to around 60 mph. Some gusty winds will spread onto the urban corridor where gusts to 40 mph will be possible overnight and into Saturday. This will result in a warm night where the winds persist.

The temperature forecast for Saturday will be a tricky one as the arctic air sneaks into northeast Colorado. Models greatly vary on the amount of arctic air that makes it into northeast Colorado.
The 2PM temperature at DEN on the HRRR is 64F, while the GFS shows 44F. Typically the colder air advances more quickly and farther westward than the models show. The morning will start off mild with temperatures expected to reach the 50s to lower 60s along the urban corridor and nearby plains. As the arctic air moves into the area temperatures are expected to fall during the afternoon and by sunset temperatures could be in the 30s or even 20s. The arctic air is expected to be shallow, only up to 7,000-8,000 feet MSL, so don't expect the cold to advance very far into the foothills.

LONG TERM /Saturday night through Friday/
Issued at 101 PM MST Fri Dec 12 2025

It's starting to feel as though the warmer temperatures are becoming a Mid-West goodbye...

We're seeing above average temperatures through all of next week with little in the way of moisture for the plains. Ensembles are showing higher probabilities, 70+ percent, of 10 to 15 degrees above average daytime highs and overnight lows all of next week.

Moisture, if we're able to get any, will be mostly confined over the high country and should be snow with a possibility, 30-40%, of a rain/snow mix in the mountain valleys. Currently targeting Wednesday for any moisture across the mountains as the upper level flow becomes more zonal and tries to wring something out. The pattern just isn't good but it's a very typical La Nina pattern for us in Colorado.

Speaking of Wednesday, windy. Yes it's further out there in time and yes confidence is increasing and yes there are uncertainties but digging into the ensembles and the larger picture we can gain some knowledge. Cluster analysis shows some pretty decent camps of stronger zonal flow with anomalous heights over the inter- mountain west. EFI and SOT from the ECE are high and low respectively in terms of wind/wind gusts meaning, the individual members are showing higher confidence in an impactful event. Even looking at NBM in DESI we have a 40-50% chance of maximum gusts at the base of the foothills exceeding 70 MPH. Now the uncertainties, does the wind stay more 290-310 degrees aloft or does it trend slightly back towards 330-350 degrees? Does the moisture content on Wednesday become too deep to disrupt any kind of thermal inversion preventing the winds aloft to be forced downward? Don't have all the answers yet and we may not until Tuesday...Chinook are tough!

We don't really lose the stronger forcing aloft with the more expected zonal-ish flow so we keep the stronger winds around through the end of the work week.

Can't forget to mention fire weather, not that anyone wants to hear it. We're dry and mild/warm, and we have enough wind to continue to dry out any early December moisture, if it's not already gone from the lower foothills, and the plains never really got it anyway. As we get into the later part of next week we see increasing potential for at least elevated fire weather conditions with the wind, receptive fuels, and lower RH values.

AVIATION /06Z TAFS through 06Z Sunday/
Issued at 1023 PM MST Fri Dec 12 2025

Despite an initial expansion of NE surface winds into KDEN/KBJC mid-evening, southwesterly drainage flow has begun to win out, and suspect it will remain sufficiently anchored over the metro to keep the bank of low stratus and FG to the NE of KDEN/KBJC overnight. With this in mind, anticipate VFR conditions to prevail for all terminals through the remainder of the TAF period, but will continue to monitor for any potential trends in stratus deck expansion closer to the metro. Periods of gustier W winds still appear likely for KBJC for the early morning hours in particular.

On Saturday, winds will turn clockwise to produce a brief W then NW component through the morning hours, before a cold front brings a more marked NE wind shift closer to 19-20Z. Occasional gusts 19-23 kts will be possible with the front. Following that, a gradual return to typical drainage flow patterns is expected.

BOU WATCHES/WARNINGS/ADVISORIES
None.