textproduct: Cheyenne

KEY MESSAGES

- Very warm temperatures will return through the area through Wednesday with widespread record highs expected Wednesday afternoon.

- Marginally high winds are possible (30 to 60% chance) for the wind prone areas of southeast Wyoming today and Wednesday. - Elevated to critical fire weather continues through Wednesday and possibly beyond. A Red Flag Warning has been issued for much of the area for Wednesday.

SHORT TERM /THROUGH WEDNESDAY NIGHT/

Issued at 300 AM MDT Tue Mar 24 2026

Record high temperatures and fire weather remain the primary concerns for the next several days. Our period of only slightly above average temperatures is coming to an end today as the powerful ridge begins to re-strengthen over the desert southwest and shift to the northeast. Expect unseasonably warm temperatures once again this afternoon as 700-mb temperatures climb to around +6 to +10C, which is generally the 97 to 99.5 percentile of climatology. All locations will once again see near record breaking high temperatures in the 70s to lower 80s across the area. Westerly winds will spread over most of the area by midday today, providing an extra boost to high temperatures today despite some cloud cover sticking around most of the day. In addition to the warmth, large-scale subsidence will help boost wind speeds in the wind prone areas today. Most models show 700-mb winds around 45 to 55 knots over the Arlington/Elk Mountain and Laramie Range areas beginning late this morning and continuing through midday tomorrow. However, pressure/height gradients are fairly unimpressive, and considerably weaker than what we'd like to see for high winds. This leads to low confidence in a potential wind event today. In-house guidance and NBM probabilities are in fairly good agreement showing probabilities around 40 to 60% for the Arlington/Elk Mountain area today, and 30 to 50% probability tomorrow. For the Laramie Range wind corridors, probabilities are a bit lower, around 20 to 40% mainly tonight and Wednesday morning. This mainly appears to be driven by the 700-mb winds and flow aloft, which should be able to mix down during the daytime hours. This was enough to issue a low confidence High Wind Watch for the Arlington area, but held off on the I-25 wind prone corridors for now.

Expect another mild night tonight as cloud cover clears, but light to moderate westerly flow prevents the development of a shallow inversion. This will set the stage for another day of unprecedented spring warmth on Wednesday. The ridge strength will peak aloft and strong warm air advection is expected ahead of an approaching upper level shortwave. 700-mb temperatures will crest between +10 and +14C, which easily exceeds the climatological maximum per the NAEFS mean. The ECWMF extreme forecast index of surface maximum temperature is hovering around 0.99 for most of the area, indicating high confidence in an anomalous warm event. In fact, the current official forecast reflects highs similar to Saturday, pushing the upper 70s in Rawlins and Laramie, and the 80s to low 90s along and east of I-25. All long term forecast sites are forecast to smash daily record highs, most by close to 10 degrees. Prior to last week, Wednesday would be an easy forecast for monthly record highs too, but values will be fairly close to the new monthly records just set on Saturday.

Record warmth combined with continued westerly winds across the area will boost fire weather concerns once again. While we will have a little more moisture present than last week's warm spell, RH is still expected to drop to 10 to 15% along and east of the Laramie Range Wednesday. As a result, there is high confidence in widespread critical fire weather conditions along and east of I-25. Further west, the slightly cooler temperatures reduces confidence somewhat, but it was still high enough to upgrade the Fire Weather Watch. Wildfire will spread rapidly under these conditions.

The last weather concern in the short term will be the shortwave trough passing to our north Wednesday evening. This feature will kick off upper level positive theta-e advection, moistening the upper atmosphere during the afternoon and evening hours. While low- level moisture will be highly limited, there should be enough above the very deep, well-mixed boundary layer to kick off some showers around mid-afternoon. This area will be mainly concentrated east of the Laramie Range, and south of a Wheatland to Alliance line (roughly). While instability forecasts are not terribly impressive, 100 to 300 J/kg of CAPE may be enough to produce some isolated lightning. The probability of lightning in the vicinity of a given location is only around 10%, but this is still concerning due to the very dry boundary layer. This could help support a few dry microbursts with gusty and erratic winds at the surface. Wetting rains are unfortunately quite unlikely (less than 10% probability) with these showers continuing into Wednesday evening.

LONG TERM /THURSDAY THROUGH MONDAY/

Issued at 300 AM MDT Tue Mar 24 2026

A potent cold front will push into the area behind the departing shortwave trough Thursday morning. This will manifest as a shift in the winds to the north or northeast along with an increase in relative humidity. Expect this to push into our northern zones before sunrise Thursday, and reach the I-80 corridor around mid morning. However, it may take until Thursday evening for improved moisture to break west of the higher terrain and reach the Laramie to Rawlins corridor. As a result, elevated fire weather conditions will continue for Carbon and Albany counties with near record high temperatures continuing, even as those to the east cool down about 20F from Wednesday's highs (and still remain about 10F above seasonal averages!) Models show the potential for strong frontogenesis Thursday afternoon as the frontal boundary stalls against the Laramie Range. Modest overrunning lift on top should produce another round of shower activity during the afternoon and evening hours. This activity will also mix with and eventually chance over to snow as 700-mb temperatures fall behind the cold front. While widespread accumulating snow is not expected, this round of precipitation will provide slightly better odds for appreciable precipitation. Probabilities for wetting rainfall (greater than 0.1" liquid) are around 10 to 25% for much of Albany, Laramie, Platte, and Goshen counties. Lower probabilities are present for other counties.

Friday will feature temperatures near seasonal averages as the surface high pressure system begins to retreat off to the east. Look for increasing southerly winds as this feature begins to move away from the area. The cycle repeats again Saturday into early next week as the powerful ridge re-strengthens once again. Lee troughing should reach the I-25 corridor on Saturday, spreading westerly and near record high temperatures across much of southeast Wyoming. By Sunday, westerlies should push back across the entire area, which will bring the potential for widespread daily record highs Sunday and Monday. This round of warmth does not appear as anomalous as last Saturday and this upcoming Wednesday. The ECMWF EFI for maximum temperatures is generally between 0.8 and 0.9 while NAEFS mean 700- mb temperatures around +6 to +8C are around the 97.5 percentile of climatology rather than obliterating monthly maximums. Models are in fairly good agreement showing mid to upper level moisture improving gradually Saturday through Tuesday. This will present the possibility for a pattern of diurnal convection in the afternoon and evening to set up during this period.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 537 AM MDT Tue Mar 24 2026

VFR conditions expected for the forecast period. Gusty winds will return to terminals between mid morning and the early afternoon. Expect gusts of 30 to 40 knots in Wyoming and 20 to 30 knots in Nebraska as some mid to high level cloud cover continues to filter through. Wind gusts will ease around sunset, expect at RWL where gusty winds may continue overnight.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Red Flag Warning from 11 AM to 10 PM MDT Wednesday for WYZ417>419-430>433. Red Flag Warning from noon to 8 PM MDT Wednesday for WYZ420>423. High Wind Watch from 9 AM MDT this morning through Wednesday afternoon for WYZ110. NE...Red Flag Warning from 11 AM to 10 PM MDT Wednesday for NEZ434>437.