textproduct: Grand Junction

KEY MESSAGES

- Warmer and drier conditions return for the weekend.

- Another push of moisture will arrive by Monday, bringing widespread moderate to heavy precipitation through midweek.

DISCUSSION

Issued at 952 PM MDT Fri Sep 25 2026

PREDOMINATELY DRY THIS WEEKEND:

High pressure builds across Colorado this weekend. This will lead to a drier weekend, with daytime highs warming by a few degrees. Moisture begins to overtake the region on Sunday, but this will mostly lead to increasing cloud cover.

WET WEEK AHEAD:

By Monday, the forecast becomes a bit more challenging. Southwest follow over the Great Basin will begin to draw in moisture from a pair of tropical systems, including Polo. PWATs will return to upwards of 200% of normal, particularly in southwest Colorado and southeast Utah. This indicates the start of another wet period through at least midweek. It is important to note that some discrepancies exist between models, with the GFS consistently showing a drier solution, whereas the Euro continues to be more bullish with the moisture. Cluster solutions also continue to be inconsistent on how to handle the moisture in addition to the upstream trough, so confidence remains low on a final solution. Bottom line is that the start of next week looks to be wetter, but whether this will be a significant/anomalous event for the Four Corners area is yet to be determined. Stay tuned for how this forecast begins to develop. Please see the Hydrology section below for more on the potential for flooding with this system.

In addition to this moisture, daytime highs will drop by a few degrees come Monday, which also means overnight lows will do the same. If you're catching what we're putting down, that would indicate snowflakes returning to the forecast for some our highest peaks and passes.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 533 AM MDT Sat Sep 26 2026

VFR conditions remain in place over the next 24 hours. Some midlevel clouds will form over the higher terrain this afternoon while high clouds move in during the evening hours. A few gusts of 15 to 20 mph will occur this afternoon as well.

HYDROLOGY

Issued at 233 PM MDT Fri Sep 25 2026

In the wake of today's precipitation, our attention will turn to the Eastern Pacific. Tropical moisture is anticipated to spread across the Desert Southwest early next week, drawing moisture from a pair of Hurricanes; Odalys and Polo. The forecast becomes increasingly complex due to a closed low currently forecast to drive across the Southwest CONUS as Hurricane Polo approaches the Baja California Peninsula. Strong southerly winds ahead of the low are expected to pull tropical moisture towards eastern Utah and western Colorado as early as Monday morning. The challenge and uncertainty in our precipitation forecast increase as the week progresses and the low traverses our southern States. Excessive rainfall is most probable over AZ and NM, attm, but the northerly extent poses a threat to our southern San Juan river basins. Current forecasts suggests 1 to 3 inches of rain over Monday morning through Wednesday. At face value, rivers and tributaries will see a bump up due to said moisture. However, localized heavier amounts could result in minor flooding across the southern San Juan foothills and communities further downstream.

Rivers have responded rapidly to recent rainfall due to saturated soils and increased runoff potential. Thus, prolonged periods of additional rainfall over these regions would trigger a similar response. The current precipitation forecast suggests larger peaks in several creeks and rivers than what has been observed over the previous 7 days. However, high end probabilistic rainfall amounts (i.e. above 90th percentile) may lead to rivers exceeding action stage to minor flooding. Most probable basins to see significant rises include; the Rio Blanco, San Juan, Piedra, Los Pinos/Vallecito Creek, and the Animas River Basins.

Convective storms and periods of heavy rainfall fed from said tropical moisture could result in localized flooding impacts across the CWA, however, confidence decreases rapidly north of the San Juans. Please continue to monitor the forecast as these systems evolve. Especially for those who reside and/or plan to recreate in the southwest quadrant of the forecast area.

GJT WATCHES/WARNINGS/ADVISORIES

CO...None. UT...None.