textproduct: Cheyenne

KEY MESSAGES

- Near record warmth and critical fire weather conditions will continue through Monday evening.

- Widely scattered high-based showers this afternoon and evening will have the potential to produce gusty and erratic winds and a few isolated lightning strikes.

- A cold front arriving Monday night will bring cooler temperatures and a chance for widespread rain and snow showers Tuesday through Wednesday night.

- Accumulating snow is expected for the higher mountains above 9000 ft in elevation Tuesday night through Wednesday evening.

- After a brief warmup Thursday, another strong cold front will sweep through the area and bring another round of rain and snow Thursday afternoon into Friday.

SHORT TERM /THROUGH WEDNESDAY NIGHT/

Issued at 300 PM MDT Mon Mar 30 2026

Another warm, dry, and windy day is underway across the area today, but changes are just around the corner. Currently, west-southwest flow aloft is supporting strong, gusty winds mainly over Carbon and Converse counties. Widespread critical fire weather conditions are present due to the windy conditions and relative humidity down below 15% once again. We have a bit of cloud cover present across the area, which is holding temperatures down a degree or two cooler than forecast for several areas, but temperatures are still well above average for this time of year. Current satellite observations shows cumulus cloud development over southeast Wyoming, in place of about 100-300 J/kg of surface based CAPE. While this isn't a lot, it should support the development of widely scattered showers which should show up shortly, and continue through the evening hours. A few isolated lightning strikes are possible, which will exacerbate the fire weather concerns if this occurs. In addition, these showers are forming with fairly high bases, and over the top of an extremely dry, well-mixed boundary layer. With the already strong background flow in place, it won't take much to boost winds to high wind criteria in some of the wind prone areas. A short-fused High Wind Warning has been issued for portions of Carbon and Converse counties, which will run through 10PM. Winds should begin to weaken around 7-8pm, but the threat for a few gusty showers prompted the decision to run the warning a few hours longer.

A shortwave trough passing to our north has supported broad lee cyclogenesis over most of our High Plains areas today. These pressure falls will begin to shift east into central Nebraska this evening, which will allow the cold front currently stalled across northeast Wyoming and western South Dakota to surge southward. Expect this to push into the Douglas to Chadron corridor around 9- 11PM, then reach I-80 around 2AM. Expect a surge in north to northeast winds behind the frontal boundary. Gusts will be consistently 35 to 45 mph for several hours behind the frontal passage, with a few gusts up to around 55 mph possible. The surface front will stall along the Laramie Range by early Tuesday morning, not quite reaching the Rawlins to Laramie corridor. Scattered shower activity will continue through the night and into Tuesday morning, but these will not amount to much, if any, precipitation.

We will have a fairly complex weather setup over our area on Tuesday. A cool airmass will be entrenched east of the Laramie Range with widespread upslope flow supporting plentiful cloud cover. Surface winds will begin the day out of the northeast and then rotate around through east to southeast by the afternoon hours. Meanwhile, Carbon and Albany county will be under a completely different airmass with strong southeast winds kicking up through the day. Expect highs about 5-10 degrees above average in Rawlins, Saratoga, and Laramie, while those to the east will range from near average to about 10 degrees below average. Despite the mild surface temperatures, we will actually have quite cold temperatures aloft tomorrow, which will produce very steep lapse rates. Along and west of the Laramie range, we will be looking at perhaps 500 to 750 J/kg of CAPE at times. Broad ascent ahead of the next trough approaching will support the development of scattered showers and thunderstorms around mid afternoon. With decent speed shear, a few strong thunderstorms cannot be ruled out. These will struggle once east of the Laramie range due to losing access to surface based instability, but we may see elevated shower and isolated thunderstorm activity continuing eastward Tuesday afternoon and evening.

By Tuesday evening, a fetch of deeper moisture will arrive, initiating moist upslope southwesterly flow in the higher mountains. Snow levels will be quite high, but accumulating snow can be expected above 9000 ft in the Snowy and Sierra Madre ranges Tuesday night into Wednesday. Expect shower activity to increase in coverage across the rest of the area as weak isentropic lift develops well ahead of the main trough axis. We should finally start to see some shower activity putting down measurable rainfall totals by this time. Over the High Plains, southeast winds will increase in strength Tuesday evening and into Wednesday morning, perhaps supporting a few gusts over 50 mph, which is fairly rare for that wind direction. This will be caused by a developing lee cyclones over central Colorado and central Wyoming dropping surface pressure there while the surface high remains strong over the northern Plains.

The main trough axis will arrive on Wednesday. Model trends have pointed more towards a weaker, slower, and more positively tilted upper level trough, which has unfortunately tempered precipitation expectations for the area. However, there will still be a decent window for widespread precipitation on Wednesday into early Thursday morning. 700-mb temperatures around 0 to -3C will setup a very marginal situation for precipitation type, but even areas seeing snow probably won't see much accumulation due to the warm surface temperatures (outside of the mountains). Overall QPF was trended down slightly from the NBM due to the disorganized nature of the event. There will be abundant moisture present, so localized amounts of over 0.5" liquid can be expected, but this will not be very widespread. Expect precipitation to clear out by around midnight Wednesday night.

LONG TERM /THURSDAY THROUGH SUNDAY/

Issued at 300 PM MDT Mon Mar 30 2026

A potent upper-level trough will come ashore the west coast on Thursday and quickly make its way eastward throughout the day. This trough will bring precipitation chances to the CWA for the end of the work week. By Thursday night, the trough will enter the western reaches of the CWA, with precipitation creeping into Carbon and Albany Counties as early as Thursday afternoon. The cold front associated with this trough will be rather strong, advecting much colder air into the region very quickly. While precipitation may start as rain Thursday afternoon, it may quickly change to snow with the frontal passage. This raises concerns for snow squall potential as there will be minor instability out west with blustery conditions from a strong MSLP gradient. A flash freeze behind the front is also in question depending how quickly temperatures drop and when precipitation arrives. Snow will likely continue into the overnight hours for areas west of the Laramie Range with some accumulation possible for the lower elevations.

Models begin to differ Friday with how to handle the upper-level closed low associated with the trough. The GFS has a more northerly track along the Wyoming/Montana border while the ECMWF takes a more southerly track along the Colorado/Wyoming border. The more northerly solution of the GFS is dryer, keeping most of the precipitation in the northern zones of the CWA. The more southerly track of the ECMWF brings the precipitation a bit farther south in the North Platte River Valley, but still mostly keeps the Interstate 80 corridor east of Cheyenne rather dry. Regardless of which solution comes to fruition, both have much colder high temperatures on Friday behind the front. Highs will mainly be in the 30s and 40s, with 50s possible in the southern Nebraska panhandle. These colder temperatures means precipitation could fall as snow, or at least a rain/snow mix. At this time, cannot rule out some lower elevation accumulations for areas east of the Laramie Range, but for now, the most confidence in accumulation remains in the high terrain.

Once the trough moves out of the region, a return to warmer and drier conditions can be expected as upper-level ridging takes its place. Cold air aloft will still be in place Saturday, so the return to above average temperatures will happen on Sunday with highs in the 50s and upper 60s.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1128 AM MDT Mon Mar 30 2026

Westerly flow aloft will prevail, while a cold front progresses southward across the terminals tonight, producing a wind shift to the north and northeast.

Wyoming TAFS...Scattered to broken clouds near 15000 feet will lower to 10000 feet this evening, then to 5000 to 8000 feet after 06Z. Winds will gust to 37 knots until 03Z, then to 25 knots until 08Z, with gusts to 24 knots at Laramie after 15Z Tuesday.

Nebraska...Scattered clouds near 15000 feet will occur until 01Z, then ceilings will lower to 6000 to 10000 feet overnight. Winds will gust to 25 knots at Chadron and Alliance until 06Z, to 25 knots at Scottsbluff until 20Z, and after 05Z, and to 25 knots at Sidney until 23Z and from 06Z to 09Z.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Red Flag Warning until 9 PM MDT this evening for WYZ417>423- 425-427>433. High Wind Warning until 10 PM MDT this evening for WYZ101-104- 110. Winter Weather Advisory from 6 PM Tuesday to 9 PM MDT Wednesday for WYZ112-114. NE...Red Flag Warning until 9 PM MDT this evening for NEZ434>437.