Marine Weather and Tide Forecast for Nunn, CO

DISCUSSION /Through Monday/
Issued at 1018 PM MDT Mon Oct 12 2026

An upper level low will be over central Nevada by 12z Tue and then will move to near the Four Corners area by 12z Wed. Will gradually see a better chc of showers along with a few tstms by Tue aftn in the mtns. Across the plains, cooler temps will occur behind a front as weak upslope flow develops. Highs will drop into the lower to mid 60 across nern CO. Any chc of showers by late aftn will be confined to areas closer to the foothills.

By Tue night, will see widespread showers across the higher terrain with snow levels lowering to 9500 ft overnight. Across the plains, best chc of showers overnight will be mainly along the I-25 Corridor with lessor chances further east.

For Wed thru Wed night, the main question is where will the upper level low track, as it begins to move from swrn CO east northeast towards ern CO. The Canadian, ECMWF and NAM have a more northern track as it moves into nern CO by 12z Thu. Meanwhile, the GFS has a more southern track with the upper level low being over east central CO. Looking at ensemble data from the ECMWF and GFS shows a more northern solution with the low being over nern CO.
Meanwhile, sfc high pres will continue to build into nern CO with the low level flow becoming ESE. Overall, with favorable QG ascent should continue to see showers/isold tstms over the higher terrain thru the aftn with snow levels down to 9000 ft by late aftn. Across nern CO, should see showers thru the aftn, especially along the I-25 Corridor with a chc across the plains. Highs on Wed, will only be in the mid 40's to lower 50's over nern CO.

By late Wed night into Thu, additional precipitation will depend on the exact track of the upper level low. If it takes a more northern track across nern CO, then best chc of precipitation will be across the higher terrain along and north of I-70 and over nrn portions of the plains. Naturally, if it were to take a more southern track across east central CO, then much of the area would have additional widespread precipitation late Wed night thru midday Thu.
Meanwhile snow levels Wed night into Thu morning may drop down to 8000 ft or so. At this time, snow amounts look to be mainly in the advisory range for mtn areas, except over the higher peaks which may have higher amounts.

For Thu aftn into Thu night, the upper level low will weaken and move east of the area. Thus, will see precipitation gradually end during the aftn hours in most areas. Highs on Thu will be in the 50's across the plains. For Thu night into Fri morning, some areas across the plains may see freezing temps with frost possible in those places that don't get down to freezing.

Looking ahead to Fri and Sat, an upper level ridge will develop over the area. This will lead to dry conditions with a warming trend.
Highs will rise into the upper 50's to mid 60's on Fri, over nern CO, and then into the lower to mid 70's by Sat.

On Sun, a very weak upper level trough will move across the area.
Latest cross-sections show very little moisture associated with this feature. Thus it will remain dry with above normal temperatures.

AVIATION /18Z TAFS through 18Z Wednesday/
Issued at 1204 PM MDT Tue Oct 13 2026

Satellite shows the stratus deck is slowly breaking, with one patch of brief clearing currently working southwest toward KDEN, with a somewhat higher deck forming behind that near 2000-3000 ft AGL. We should see a slow but continued breaking of the deck with additional daytime heating, with mostly VFR conditions for a few hours late this afternoon and early evening. Then low clouds will settle in again and overspread the TAF sites, most likely 03Z-06Z and then lowering to IFR/LIFR with ceilings down to 500 ft or less starting 06Z-08Z. These will hold through all day Wednesday. One batch of showers will attempt to move across the airports 23Z-04Z, with more widespread showers and drizzle likely affecting KBJC after midnight. KDEN and KAPA would be more prone to the drizzle side through 16Z since moisture is quite shallow there. Showers will become more widespread across all TAF sites after 21Z Wednesday, with a low (10%) chance of thunder.

BOU WATCHES/WARNINGS/ADVISORIES
Winter Weather Advisory from noon Wednesday to 6 AM MDT Thursday for COZ031-033-034.