textproduct: Grand Junction

KEY MESSAGES

- Red Flag Warnings are in effect for portions of the central Colorado mountains on Saturday.

- A chance for showers and thunderstorms remain in the forecast for Saturday and Sunday. Some dry thunderstorms will be possible, posing a threat of new fire starts.

- High pressure builds in next week bringing a return to well above normal temperatures, gusty winds, and dry conditions. Critical fire weather conditions look to continue.

DISCUSSION

Issued at 1013 PM MDT Fri Jun 12 2026

A strong mid-level pool of moisture has risen into northern Arizona today per water vapor imagery. Ensembles indicate that this pool will stagnate and the bulk of the moisture will fail to move much further north towards our CWA. However, milder mid- level moisture has and will continue to traverse beyond the southern Colorado and Utah borders to provide areas around the Four Corners and San Juans with some cloudier skies and an uptick in precipitation potential on Sunday. The lack of surface moisture will hinder the chances of wetting rainfall though. Moisture spans a deeper layer over the San Juans, and so conditions are more favorable for wetting rain here. But across low-lying terrain, deterministic models are in strong agreement that a deep inverted-V, likely up to 500mb, will be present. Per the NBM, areas around the Four Corners are extremely unlikely (<10% chance) to see above a tenth of an inch of rainfall. Further east along and south of US-160, chances are higher, but still not likely, with chances as high as 45%. And yet, in these regions, lightning potential spans anywhere from a 20 to 50% chance. Uncertain storm coverage and a large spread in NBM QPF is still resulting in a lack of confidence on the dry thunderstorm (and new lightning ignitions) threat, so we cannot definitively say if this threat will manifest or not. We will continue to watch model guidance evolve for this system.

Sunday presents the only "good" chance of seeing precipitation throughout the short-term period as northwesterly flow develops across the Intermountain West and the moisture pool is shoved back into the Desert Southwest. Through Wednesday, and possibly beyond, below-normal PWAT's again dominate the region and hot, dry, and windy conditions are once again favored.

AVIATION /06Z TAFS THROUGH 06Z SUNDAY/

Issued at 1129 PM MDT Fri Jun 12 2026

Expect VFR conditions through the TAF period. Light drainage winds overnight will become westerly winds gusting 20 kts between 18Z and 03Z. A surge of mid level moisture moving up from the southwest will produce isolated showers and thunderstorms across the southern mountains after about 15Z with convection pushing farther north to the I-70 corridor by 00Z. Due to the dry lower atmosphere, most of these showers will be in the form of virga producing strong downbursts and outflows along with occasional lightning. Look for convective coverage to increase after 00Z south of I-70.

FIRE WEATHER

Issued at 1013 PM MDT Fri Jun 12 2026

Weekend fire weather conditions have noticeable diminished, though some locations across the CWA will still sit underneath Red Flag conditions over the next couple days. On Saturday, dry surface conditions and gusty winds will mostly be confined to the central Colorado mountains with more isolated critical fire weather conditions across the northern CWA. Red Flag Warnings are in effect on Saturday for fire zones 205 and 293. On Saturday, a push of moisture from the south creeps over the region, bringing a mild increase in relative humidities. Lower elevation valleys will mostly sit below 15% still, but broadening in the region-wide pressure gradient should prevent any Red Flag Warnings prompted by dry and windy conditions. Where Red Flag concerns may arise on Sunday will be the presence of dry thunderstorms. Though low-level moisture will be improved, it still won't be "good," and rainfall may be unable to reach the ground in many locations. Spotty morning cloud cover makes it difficult to pinpoint where thunderstorms will form, but in general, the Four Corners region and eastwards across the southern slopes of the San Juans will be the areas of greatest concern. Of note, dry thunderstorms cannot be ruled out for Saturday either, but the likelihood is much lower (<15% of lightning on Saturday compared to 25-50% chance on Sunday).

Widespread Red Flag Conditions due to low RH and strong gusts return on Monday and persist at least through Wednesday.

GJT WATCHES/WARNINGS/ADVISORIES

CO...Red Flag Warning from 1 PM to 8 PM MDT Saturday for COZ205-293. UT...None.