textproduct: Cheyenne

KEY MESSAGES

- Another round of near record warmth and critical fire weather conditions is expected to begin today and continue through Monday.

- A few high-based virga showers will be possible each evening, bringing the potential for gusty and erratic winds and isolated lightning.

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

SHORT TERM /THROUGH MONDAY/

Issued at 315 AM MDT Sat Mar 28 2026

Warm temperatures and critical fire weather remain the primary concerns of the day today. After one day of near average temperatures yesterday, the usual programming is resuming today as the stubborn, powerful ridge of high pressure aloft re-strengthens over the western CONUS. Rapid warm air advection is already occurring aloft this morning as the surface high pressure responsible for the cooler weather retreats to the east. The nocturnal low-level jet has generally proceeded as expected, and will gradually weaken over the next few hours, dying down by mid morning over western Nebraska. Expect westerly winds to mix down in Wyoming around mid morning as well, supporting rapid warming. 700-mb temperatures will climb to around +6 to +9C by midday today, and remain there through Monday evening. For most of the area, this will hover between the 97.5 and 99.5 percentiles of climatology. Corresponding highs at the surface are expected to range generally from the 70s to mid 80s with the higher temperatures in the typical spots of western Nebraska and the Torrington area. Highs will not vary much from one day to the next, but we may see slightly cooler highs to the west on Monday while areas to the east see slightly warmer highs. At least a couple of daily record highs are expected each of the next three days, but the monthly record highs set earlier this month are expected to be safe through this round of warmth. Widespread warmth will support minimum afternoon relative humidity between 8 and 15 percent each day. Due to more cloud cover than the last few warm spells, overnight lows may actually be a touch warmer. Expect poor overnight RH recoveries, exacerbating the fire weather conditions.

The other component of the fire weather equation will be the wind. Look for widespread westerly winds gusting 35 to 50 mph in southeast Wyoming today. There is lower confidence in the gusty winds reaching western Nebraska. This will depend on how quickly the surface trough can push to the east. So, there is high confidence in widespread critical fire weather conditions in Wyoming, and elevated conditions in Nebraska. Brief critical conditions could occur in western Nebraska if winds end up stronger than forecast. For Sunday, expect westerly winds to spread across the entire area, but overall wind speeds will be a little lower than today. Look for gusts of 25 to 45 mph across the area, with the stronger gusts in Wyoming as usual. Monday will see some enhancement of the pressure gradient in advance of an upper level shortwave trough progressing across the northern Rockies. Expect the strongest winds of the 3-day warm spell on Monday, leading to widespread critical fire weather conditions. We will also need to watch for marginally high winds returning to the wind prone areas. Current probabilities range from about 30 to 50%.

Lastly, each of the next three days will bring a chance for widely scattered evening virga showers. While the well-mixed boundary layer is expected to remain very dry, forecast soundings show decent moisture moving into the 500 to 200-mb layer. These moisture intrusions will be associated with weak vorticity maximums moving through the area just after peak heating each day. A little boost of synoptic lift from the vort-max combined with some modest moisture aloft should support the development of widely scattered shower activity. This will be extremely high- based and over the top of a parched boundary layer. Therefore, anything more than a few sprinkles reaching the ground is highly unlikely. However, there may be enough mass loading to observe gusty and erratic winds at the surface near this activity. Instability will be quite limited, but 100-200 J/kg of CAPE each afternoon could support a handful of isolated dry lightning strikes. This activity will be possible each evening on Saturday, Sunday, and Monday.

LONG TERM /MONDAY NIGHT THROUGH FRIDAY/

Issued at 315 AM MDT Sat Mar 28 2026

The extremely persistent blocking ridge responsible for the exceptionally warm and dry second half of March this year will finally break down for the last day of the month. As the ridge aloft shifts east, the door will open to Pacific troughs to move into the interior west, with access to some moisture. The first of these is expected to pass to our north on Monday evening. While the upper level disturbance will pass too far north for much precipitation here, it will send a strong surface cold front down the eastern side of the Rockies. This will arrive sometime Monday night through our area, bringing an abrupt drop in temperatures and a wind shift to gusty north or northwest winds behind the boundary. This front looks to be much more well defined than the one that passed through on Thursday. Decent frontogenesis along the boundary may also support some rain showers mixing with and changing over to snow. Precipitation potential Monday night into Tuesday morning looks fairly limited.

The second phase of this looks a little more interesting. The axis of the surface ridge looks to move through the area around midday Tuesday, as the frontal boundary is stuck up against the higher terrain, struggling to move west of the terrain barrier. Meanwhile, another shortwave trough will approach the area. This system looks weaker, but will take a more favorable track across the central Great Basin and into the central Rockies rather than passing to our north. Model guidance shows overrunning isentropic lift on top of the stalled frontal boundary developing Tuesday morning and possibly continuing into Wednesday morning. Positive theta-e advection should support the development of some precipitation. Precipitation type is somewhat uncertain due to marginal 700-mb temperatures between -2C and 0C, colder surface temperatures and the warm air advection aloft. Regarding precipitation amounts, this is not expected to be a drought-busting event by any means, but we will see the highest odds for a wetting rainfall we have seen in weeks. Probabilities for 0.1" of liquid precipitation or more are highest along the I-80 corridor, reaching 50 to 70% between Elk Mountain and Cheyenne, and dropping off to 30 to 50% around Kimball, Sidney, and Rawlins. Probabilities range from 20 to 40% north along and north of the North Platte River, so this event is unlikely to provide much relief to those areas.

Our area will be between troughs on Thursday, which should allow for temperatures to climb above average once again, but not up to the record breaking heights that have been quite common recently. Thursday will also bring the potential for another round of strong winds with increasing west to southwest flow aloft in advance of the next upper level trough.

The next potential system will arrive in the Friday to Saturday period, but the details regarding this system are still highly uncertain. LREF ensembles are split nearly exactly 50/50 between two possible outcomes. The first scenario is supported by the deterministic GFS, about 75% of GEFS members, and about 30% of ECWMF ensemble members. This would involve a powerful but very progressive Pacific trough passing north of our area on Friday. Most precipitation would fall on Friday, with overall lower totals expected. Mean QPF in this cluster is generally less than 0.1", but some locally higher amounts would be possible in the mountains and along the Pine Ridge. Fairly widespread strong northwest winds could also be expected. The other scenario, supported by 70% of ECWMF members and 25% of GEFS members favors a much slower, potentially closed, upper level low traversing further south. This case would mean more widespread precipitation, mainly on Saturday, and a much longer cool down. Mean QPF is around 0.2 to 0.4" along the I-80 corridor (lower amounts further north). This scenario would also probably be less windy, but gusty north to northwest winds could still easily kick up behind the departing closed low outside of the current operational forecast window.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 530 AM MDT Sat Mar 28 2026

VFR conditions expected for the forecast period. Southerly winds in the Nebraska panhandle will weaken by about 16z and then remain fairly light through the daytime hours. The direction may be variable at times. In Wyoming, expect westerly winds to pick up around 16z with gusts of 25 to 35 knots expected through sunset. A few gusts over 40 knots are possible.

This evening, widely scattered high-based virga showers are expected to develop. While rainfall is unlikely to reach the ground, RWL, LAR, CYS, and SNY will have the potential to see gusty and erratic winds near this activity. A few lightning strikes cannot be ruled out. Shower activity will wane after midnight.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Red Flag Warning from 10 AM this morning to 9 PM MDT Monday for WYZ417>423-425-427>433. NE...Red Flag Warning from 10 AM Sunday to 9 PM MDT Monday for NEZ434>437.