textproduct: Grand Junction

KEY MESSAGES

- A surge of moisture arrives Monday and leads to an uptick in shower and thunderstorm coverage tomorrow...peaking on Tuesday.

- Several days of increased fire weather concerns arrive mid to late week as a large system settles over the Intermountain West.

DISCUSSION

Issued at 1035 PM MDT Sun May 24 2026

The 25/00Z H500 hand analysis map is showing a tight omega pattern with lows off the SoCal coast and eastern Texas and high pressure over the central/southern Rockies. We circulated just enough moisture over a deep elevated mixed layer to create widely scattered convection during the peak heating hours. Most of this was in the form of virga...however a few showers and storms popped north of I-70 and measured some precipitation. The most noticeable feature on the map however is the anomalous low sitting in the Gulf of AK. This large cyclone will be driving the sensible weather over the West through much of the coming week. As this system digs into the PacNW over the next 24 to 36 hours it will kick the SoCal low into the Southwest tomorrow and across our CWA on Tuesday as an open wave. The strengthening southerly flow ahead of this system will pull SubTrop moisture across the 4 Corners region and bring an uptick in shower and thunderstorm coverage...peaking on Tuesday as the open wave lifts through. Overall the large scale ascent is stronger tomorrow but much of this will be wasted on erasing the inverted V profile. That is not to say a few of the more organized storms will be capable of moderate to heavy rainfall...just these will be limited. The biggest concern remains gusty outflow winds but storms and burn scar interactions will be closely monitored. Allegedly a better\moister profile on Tuesday should lead to better coverage of storms with high precipitation rates...and models continue to paint the Colorado mountains with the highest amounts. By Wednesday the upstream low in firmly anchored over the Intermountain West and the southerly fetch around this will be tapping into drier air. This means we will be transitioning to a warm...dry and windy regime and a quick switch back to fire weather concerns through through the late week period. As the low begins to open and eject northeastward by Saturday another weak push of moisture and cooler air could ease the fire weather threat. Of course this low is being pushed out by yet another robust upstream cyclone dropping out of the high latitudes so unsettled and cooler than normal trends may set up for the start of summer.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1126 AM MDT Mon May 25 2026

As moisture continues to push into the region, cloud cover is increasing, as are chances of precipitation. All terminals have a chance of seeing rainfall today. The most likely locations to see rain will be KASE, KMTJ, KTEX, and KGUC. Potential is lowest at KGJT, KHDN, KVEL, and KCNY. Thunderstorms may develop over the high terrain too, and gusty outflow winds near these storms could impact multiple terminals. Uncertainty remains low regarding the potential for cigs dropping below ILS breakpoints later in the TAF period, but this possibility cannot be ruled out. Additionally, all storms pose a slight threat of dropping vis to MVFR for brief periods.

GJT WATCHES/WARNINGS/ADVISORIES

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