textproduct: Cheyenne

KEY MESSAGES

- Hot temperatures will return to the area today and continue into early next week, producing near record highs Saturday through Monday.

- Widely scattered high-based showers and thunderstorms will be possible over the weekend. The primary hazard will be gusty winds.

- Another surge of monsoon moisture will arrive Monday, increasing rainfall chances for the early part of the work week.

SHORT TERM /THROUGH SUNDAY NIGHT/

Issued at 330 AM MDT Fri Jul 24 2026

The monsoon is beginning its break today as mostly clear skies filter in across the area. While dry air is pushing in aloft, low level moisture remains plentiful, which is producing some fog and low cloud cover over western Nebraska this morning. Expect this to clear out by mid morning as winds turn westerly from west to east across the area today. On the synoptic scale, the upper level ridge will amplify over the Four Corners region beginning today, sending temperatures soaring over the next few days once again. The warming will occur aloft first, with 500-mb temperatures expected to exceed climatological maximums by this afternoon while 700-mb temperatures remain "only" around the 90th percentile. Forecast soundings show an inversion around 550-mb this afternoon, that should limit convective instability. However, models are showing this feature as considerably weaker compared to 24-hours ago. So, while today's convection activity should still be limited, we may be able to get a few isolated high-based showers or storms going, mainly over Carbon, Albany, and Laramie counties.

The heat ramps up further on Saturday. 700-mb temperatures will surge up to +17 to +20C Saturday afternoon per the NAEFS mean, easily above the climatological 90th percentile and close to the 99th. This will edge up slightly further for Sunday. Saturday's highs will be within a few degrees of daily record highs at most locations, ranging from the lower 90s in the Rawlins to Laramie corridor, to the mid 90s around Cheyenne, and 100s for the remainder of the High Plains below 5500 ft in elevation. Sunday's highs look to be 1-3 degrees warmer than Saturday, which will put numerous daily record highs in jeopardy. Scottsbluff and Torrington have a 50/50 chance to exceed 105 degrees, while Chadron's probability is around 80%. Chadron even has approximately a 10% chance to exceed 110 on Sunday. With high temperatures expected to be around the climatological 99th percentile Saturday through Monday, decided to issue a long duration Heat Advisory beginning midday Saturday and continuing through Monday evening. Saturday and Monday are fairly marginal for local advisory criteria, but Sunday should exceed criteria easily. In addition to the warm daytime temperatures, overnight lows will be quite warm for our area. On Saturday night, models show a modest nocturnal low-level jet developing, keeping breezy southerly winds going overnight in the Nebraska panhandle. Downsloping from the Pine ridge in Sioux and Dawes counties may keep temperatures from dropping below the mid to upper 70s Saturday night. If winds stay blowing through the morning, it is not out of the question for Chadron to challenge it's all time warmest minimum temperatures of 82 degrees. As a result of the warm overnight temperatures, northern Sioux and Dawes counties will be approaching criteria for an Extreme Heat Warning. Confidence was too low to issue this product currently, but an upgrade of the existing Heat Advisory could be needed if confidence improves later.

While the main story this weekend will be the heat, we will also have elevated to near critical fire weather conditions returning to portions of the area. The airmass will not be really all that dry, even in the lower levels, but the exceptionally hot temperatures will manage to push RH to near critical values anyway. Confidence in the winds being consistent enough to warrant Red Flag Warnings is low at this time, but we will need to watch this over the next few days. As the low-levels warm this weekend, we will actually see a very slight cooling aloft. The result will be steeper lapse rates and a bit more instability Saturday and Sunday. Moisture aloft will also remain fairly decent through this heat wave, though this will be on top of deep inverted-v boundary layers. Expect to see widely scattered high-based showers and isolated thunderstorms developing during the afternoon on Saturday and Sunday. These won't be dry in a strict sense, but the probability for wetting rainfall is pretty low. Still, this activity will have the potential to produce dry (ish) microbursts, and potentially severe (>58 mph) wind gusts. The NBM is not really picking up on any storm potential whatsoever, so PoPs were manually increased above this to include the mention of a slight chance for showers/storms in the official forecast. This also looks like an excellent set up for heat bursts both Saturday and Sunday evenings.

LONG TERM /MONDAY THROUGH THURSDAY/

Issued at 330 AM MDT Fri Jul 24 2026

Monday will be another hot day across the area, though daily highs should be 1-3 degrees cooler than Sunday. The persistent, powerful ridge aloft will shift slightly eastward of its weekend position over the Four Corners, opening up the tap for another surge of monsoon moisture into our area. NAEFS mean precipitable water climbs back to the climatological 90th percentile by late Monday and remains there through at least Wednesday. A shortwave trough will also push through late in the day on Monday, enhancing lift across the area. As a result, we can expect to see an increase in shower and thunderstorm coverage on Monday, Tuesday, and possibly Wednesday. In addition, we will see an increase in the potential for these storms to produce appreciable rainfall beyond just gusty winds. Temperatures are expected to remain warm (particularly overnight), but we will be closer to seasonal averages Tuesday onwards compared to the weekend heatwave.

Ensembles show a gradual decrease in precipitable water Thursday onward as the upper level ridge very slowly retrogrades back to the west. Towards the end of the forecast period, the ridge position is in a much more unfavorable position for potent monsoon surges like we saw over the last few days, but ample recycled moisture (and perhaps stronger forcing than a typical monsoon surge) should keep daily chances for scattered showers and thunderstorms in the forecast.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 531 AM MDT Fri Jul 24 2026

Leftover moisture has indeed produced fog and low clouds this morning in the Nebraska panhandle. This has reached LIFR at AIA, which should thin and break up over the next 2-3 hours. At BFF and CDR, expect VIS generally in the 4 to 6 mile range until 14z or so, but a brief drop into IFR cannot be ruled out.

Otherwise, expect VFR conditions to prevail for the rest of the TAF period. Northwest winds occasionally gusting 20 knots can be expected today, which will lighten up in the late afternoon. There is a slight (10%) chance for a few isolated showers in Wyoming this evening. These could lead to gusty/erratic winds, but the probability was too low to add more than a PROB30 group for RWL at this time.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Heat Advisory from 11 AM Saturday to 9 PM MDT Monday for WYZ101-102-107-108-118-119. NE...Heat Advisory from 11 AM Saturday to 9 PM MDT Monday for NEZ002-003-019>021-054-055-095-096.