textproduct: Grand Junction

KEY MESSAGES

- Shower activity is less widespread today, but another round of strong winds impact the area Sunday afternoon with gusts up to 50 mph expected, including higher around favored terrain.

- A cold front arrives Monday morning, setting up for multiple days of near or below-normal temperatures.

- Valley rain and mountain snow is expected beginning Monday and lasting for the majority of the week.

DISCUSSION

Issued at 1141 AM MDT Sun Apr 12 2026

ISOLATED SHOWERS AND THUNDERSTORMS

Some generally mid-to-high-level cloud cover has developed across portions of the CWA ahead of a potent shortwave trough, which is currently situated near northern California. Per deterministic models, this low pressure system will make its slow approach to the region over the next couple days. Moisture amidst the resultant southwesterly flow over the next 24-36 hours is near-normal though, keeping storm development mostly isolated through Monday morning. Regardless, CAM's are picking up on stronger thunderstorms this afternoon across northeastern Utah where PVA is strongest. With inverted-V soundings expected in these regions and some CAM guidance noting instability matching yesterday, there exists the possibility for more powerful outflow gusts >45 mph again today. Further south across the San Juans, moisture may still be sufficient enough to produce some predominately orographically-driven showers with a lower likelihood of thunderstorms due to less-favorable dynamics.

STRONG WINDS TODAY

A second effect of the approaching trough is the tightening pressure gradient forecasted for today, and the resulting gusty synoptic winds. Aside from any outflow-driven gusts, look for areas primarily within the Yampa River Basin, Uinta Basin, and along the I-70 corridor to produce 30-50 mph gusts this afternoon. Wind advisories are in effect for some of these locations as a result. South of I- 70, valley gusts could reach 35 mph, though these wind speeds are expected to be more localized. As a cutoff low detaches from the shortwave tomorrow, we will fall under a region of weaker flow, hence reducing peak afternoon gusts, though breezy winds will still be possible.

COOLER AND WETTER THROUGH THE WEEK

Colder-than-normal temperatures have been hard to come by thus far this year, but the passage of a cold front ahead of the low tonight will kick off several days of anticipated near- or below-normal highs. By Tuesday, temperatures fall to 5-15 degrees below normal, with the most anomalously low temperatures located across the higher elevations of the San Juans.

On Tuesday, a shot of moisture from the south will prompt a rise in PWAT's to 150-200% of normal, which, when paired with the favorable upper-level dynamics, will bring widespread precipitation to the region. How far temperatures drop will have notable impacts on where we will see rain versus snow, with current NBM 50th percentile projections dropping snow levels from ~8000 ft to ~7000 ft on Tuesday. Snow ratios are also highly variable still, meaning that overall confidence in snow accumulations for our mountains remains low. Nonetheless, advisory-level snowfall is becoming more likely, with NBM guidance sitting at a 50-75% chance of 6+" for portions of mountain zones. Stay tuned for further elaboration on the details of this storm over the coming forecast updates.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 1141 AM MDT Sun Apr 12 2026

Strong southerly winds aloft are already mixing down to the surface late this morning in some areas with gusts in the 30 to 50 mph range expected this afternoon due to a strong jet aloft. VFR conditions are expected to prevail with FEW to SCT mid and high cloud cover. Clouds increase this evening with a few showers developing but confidence is low on impacts to TAF sites due to limited coverage. LLWS will occur overnight in some areas with winds remaining breezy at times.

FIRE WEATHER

Issued at 1141 AM MDT Sun Apr 12 2026

Localized red flag conditions are expected to occur primarily across the lower Yampa River Basin today. Gusts are a near slam dunk to hit red flag criteria and a wind advisory is in effect as a result. Where things are iffy are RH values. Hi-rez model guidance just keeps sub-15% RH too localized, and blended guidance is too borderline to justify highlights. Regardless, even if red flag criteria are not met, it is extremely likely that conditions will be close across the majority of the Yampa River Basin between 2-6pm. Colder, wetter conditions settle in tomorrow, effectively halting any localized red flag potential.

GJT WATCHES/WARNINGS/ADVISORIES

CO...Wind Advisory until 8 PM MDT this evening for COZ001-002. UT...None.