Security-Widefield, CO Weather

Key Messages

- Isolated showers/storm possible this afternoon.

- Periods of heavy rain for the Continental Divide, especially across the San Juan Range starting tomorrow afternoon and continuing through the day Friday.

- Heavy rain on top of saturated soils and higher elevation snow already in place will bring the threat of flooding, with rock/mud slides also possible along the ContDvd.

- Generally warm and dry across the plains through the rest of the work week, with cooler and more unsettled weather for the weekend into early next week.

Short Term

Issued at 147 PM MDT Tue Oct 20 2026

Current water vapor imagery and upper air analysis has generally weak west to southwest aloft across the region, with a weak short wave embedded lifting out across south central Colorado at this time. Regional radars have a few showers across the Front Range early this afternoon, satellite imagery indicating a line of CU developing across the Raton Mesa/southern I-25 Corridor at this time.

With that said, can't rule out a few showers/storms across the Raton Mesa through the southern tier through the rest of the afternoon, where SPC meso-analysis has a few hundred joules of CAPE at this time. Otherwise, should see clearing skies through the evening, with increasing moisture within increasing southwest flow aloft spreading mid and high level clouds across the region through the day on Wednesday. With the increasing available moisture, models are indicating CAPE of 400-800 j/kg across western Colorado tomorrow afternoon, leading to scattered showers and thunderstorms across the higher terrain along and west of the ContDvd. Some stronger storms could produce heavy rainfall, along with small hail and gusty outflow winds up to 45 mph. Temperatures tomorrow will remain above seasonal norms, with highs mainly in the 70s across the plains and in the 50s and 60s across the higher terrain.

Long Term

Issued at 147 PM MDT Tue Oct 20 2026

Model continues to be in good agreement through the end of the work week, with transitory upper ridging building across eastern Colorado through Thursday, as southwest flow increases across western Colorado ahead of an eastern Pacific storm system digging into the Great Basin. Model data supports abundant sup-tropical moisture becoming entrained within the southwest flow aloft, with PWATS of 0.8 to over 1 inch (200-300 percent of normal) moving across the region through Thursday. This, along with increasing orographic flow, and uvv associated with the Pacific system moving across the Great Basin, will lead to increasing coverage and intensity of precipitation along and west of the Continental Divide Wednesday night, with the heaviest precipitation expected Thursday into Thursday night, as the main system starts to lift out across the Great Basin into the Northern Rockies.

Latest model data continues to support qpf of 1 to 3 inches along and west of the ContDvd through this period, with the greatest amounts expected across the San Juan Mtns, where locally up to 4 inches of liquid precipitation will be possible. The Pacific origin of the system is expected to keep snow levels around peak level (at and above 12,000 feet) through the duration of the heavy precipitation event (at least through Thursday night), leading to concerns of river and stream flooding as well as the potential for rock/mudslides across the higher terrain of the ContDvd. The area of greatest concern remains across the San Juan Mtns, with already saturated soils from previous precipitation last week, as well the potential for heavy rain on top of snowpack already in place, with SNOTEL data indicating SWE 3/4 to 1" across the San Juans at this time. With that said, we have issued a Flood Watch for the eastern San Juans and the Upper Rio Grande Valley (Zones 68 and 67) starting at 18Z Wednesday with the potential for heavy rainfall from thunderstorms, and continuing through the day Friday, when said embedded sub-tropical moisture plume pushes east of the area. Those living or traveling across the southwest mountains should stay weather aware through the rest of the week, and have multiple ways to receive weather warnings.

Further east, with the transitory ridge, warm and mainly dry conditions will be in place, with chances of showers spreading east across the plains in later Thursday, as the Pacific system lifts out across the Northern Rockies.

While models continue to indicate run to run differences, however latest data supports the main system lifting north and east across the Northern Rockies on Friday, with secondary energy hanging back across the Four Corners region. The northern passing system sends a front down across the plains on Saturday, as the secondary energy slowly lifts out across the region through the day Monday. This will bring much cooler temperatures and periods rain and snow (snow levels down to between 8000-9000 feet) through early next week.

Aviation

Issued at 1054 PM MDT Tue Oct 20 2026

VFR high clouds will spread into all three TAF sites by Wednesday morning. Otherwise, diurnally driven winds will become dominated by southerly flow in the afternoon around 10-15 kts. A round of showers and thunderstorms will move across the San Luis Valley in the evening and will carry a PROB30 for -SHRA after 01z...with highest probabilities between 02Z-05Z.