textproduct: Pueblo

KEY MESSAGES

- Fog/low clouds expected to redevelop over a good part of the plains late this evening and last through tomorrow morning.

- Warm and increasingly windy next week, with a chance for critical fire weather conditions Wednesday.

- Snow showers possibly returning to the central mountains mid/late week.

SHORT TERM /THROUGH SUNDAY/

Issued at 215 PM MST Sat Dec 13 2025

Short Term...Rest of today through Tomorrow...

Well defined sharp boundary was noted over the fcst area early this afternoon. The very warm downslope air (60s/L70s) was noted over the general I-25 corridor region while farther east temps were in the 40s and 50s. The warm air did extend a bit east down along the Raton Mesa region as temps were in the U60s at KSPD while in far SW KS temps were in the 30s. Downslope was affecting the valleys of the upper and mid Arkansas river valleys was temps were in the 50s and 60s this region. In the interior valleys (SLV) temps were in the 40s, with 30s in the snow covered areas of the N SLV. Mtns were generally in the 20s. Except for some passing cirrus, skies were clear.

For the rest of today, the cool front just east of the greater I-25 corridor region should begin to push west this afternoon and the cooler air will move back across the I-25 corridor regions. Once this occur, the westerlies will shift to easterlies and temps will cool off several degrees, and RH values will increase.

The main concern with the return of the cooler air will be tonight as RH values increase to 100% over a good part of the plains and expect widespread low clouds and fog over a good part of the region by late evening, with the fog lasting well into tomorrow morning over quite a few locations. However, guidance is indicating the fog cool air will be very shallow up in El Paso county, and the low clouds and fog should only reach up to the 6000 foot contour, with areas above this elevations remaining most ly clear tonight. I do expect that we will eventually need another dense fog advisory tonight for a good part of the plains.

For tomorrow, the fog below about 5500 feet may last through the morning hours and may not clear out until the afternoon hours. Max temps tomorrow will be sharply cooler (especially compared to the max temps along the I-25 corridor today), with readings in the upper 40s below 5500 feet, and 60s over the plains above 5500 feet. Valleys will see temps in the 40s to L50s, with 30s and 40s mtns.

LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/

Issued at 241 AM MST Sat Dec 13 2025

Weak upper low drifts through the swrn U.S. upper ridge on Mon, but only impact on srn CO weather will be to keep winds rather light, as strong mid/upper nw flow is briefly disrupted by passing system.

Starting Tue, flow across the wrn U.S. becomes more zonal, as upper ridge is suppressed off the California coast, bringing warmer temperatures and stronger winds to srn CO for much of the week. Wed looks like the windiest day, as upper jet will sag southward into nrn Colorado, and 700h flow across srn CO increases above 40 kts. Ahead of the jet's arrival, brief window for some mountain wave strong winds possible Wed morning, as weak reverse shear profile develops, before jet moves overhead and wave breaks down by afternoon. Still a lot to timing/location details to be worked out, but ensemble guidance suggests a near 50 percent chance of winds above 50 mph over much of the higher terrain along/west of I-25 Wed/Wed night. Fire danger will increase as well on Wed, as minimum relative humidity falls off toward 15 percent across the I-25 corridor and portions of the southeast plains during the day. Still breezy to windy Thu/Fri with jet overhead and strong mid-level flow, while snow showers return to the higher peaks of the central mountains as moisture and weak energy race eastward across the Continental Divide. Maxes may briefly cool Thu with a weak cold front, before deeper mixing and warmer air return on Fri.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1010 AM MST Sat Dec 13 2025

KALS...

VFR next 24 hours with light winds.

KCOS...

Confidence in the TAF fcst for KCOS between 05 UTC and 12 UTC is low.

A back door cool front will move over the taf site around 14/20UTC shifting the winds to upslope. Later tonight, a period of IFR/LIFR will be possible around the midnight hour and could last until around 09UTC, then expect VFR.

Confidence is high that an area of low clouds on dense fog will form over the Colorado southeast plains and move towards the mountains, but confidence is low on how far west it will get (Will it reach the KCOS terminal area or not??). A light north wind should form after 09 UTC and should push the low clouds and fog out of the immediate KCOS area.

KPUB...

A back door cold front should push across KPUB by early to mid afternoon. Later this evening/tonight, confidence is high that low cigs/fog (possibly dense) will move in after 06 UTC and remain over the KPUB area through the rest of the fcst period.

PUB WATCHES/WARNINGS/ADVISORIES

None.