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 FRIDAY NIGHT/

Issued at 200 PM MDT Tue Mar 24 2026

Limited changes to the short-term forecast period today with gusty westerly winds present across most of southeast Wyoming. Surface observations in the north Snowy Range foothills and I-80 summit region prompted an upgrade to a High Wind Warning for both of these forecast zones. Along the I-80 summit, the High Wind Warning will last until 9pm tonight. Short-term high-resolution guidance has not picked up on this high wind event very well at all. The logic used for timing in this event is more based on when surface winds are expected to slightly decouple from the mean flow, thus greatly reducing the threat of 50 knot winds along the I-80 summit. Farther west, the North Snowy Range foothills have seen a few gusts over 50 knots this afternoon along I-80. The upgrade to a High Wind Warning will last through the previous Watch period, ending at 18z on Wednesday. Here, forecast guidance including in-house machine learning supports around a 50% chance of high wind thresholds through tomorrow morning.

The previous forecast discussion detailing the record warmth and fire weather threats for Wednesday are as follows:

Expect another mild night tonight (into Wednesday morning) 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 next 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.

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Finally, cooler weather with easterly post-frontal upslope flow will move in on Thursday behind a cold front passage. Thick low- level cloud cover is likely on Thursday through Friday with forecast soundings showing near-saturation in the lowest few thousand feet. Low clouds and possibly fog in the Laramie Range, as well as some light drizzle/snow showers in the higher elevations, are all possible on Thursday. Short-term guidance suggests the period of time of most favorable moisture/upslope flow on Thursday evening into Thursday night when a few hundredths of an inch of liquid are possible, especially from Cheyenne westward into the southern Laramie Range. By Friday morning, the base of the trough will pass through and mid-level temps will bottom out. Given how anomalously warm temperatures have been lately, it will feel quite chilly with lows in the mid to upper 20s throughout southeast Wyoming and western Nebraska. However, these low temperatures are exactly average for late March! Expect a similar story for afternoon highs on Friday -low to mid 50s will feel chilly but in fact are actually average for this time of year. Skies may eventually scatter out on Friday afternoon, especially in the northern portions of the CWA from Douglass through Lusk as well as in the Nebraska Panhandle by sunset.

LONG TERM /SATURDAY THROUGH TUESDAY/

Issued at 200 PM MDT Tue Mar 24 2026

- The weekend will be dry and mild. Increasing chances for showers will occur for Monday and Tuesday as a weather disturbance and cold front approach the forecast area.

Friday night-Saturday...West northwest flow aloft continues with a decent warming trend as 700 mb temperatures rise to near 7 Celsius on Saturday, yielding high temperatures in the upper 60s to mid 70s. Dry with limited low and mid level moisture.

Sunday...The warming and dry trend continues as the flow aloft backs to westerly, inducing surface trough development across our forecast area. 700 mb temperatures near 9 Celsius will produce maximum temperatures in the 70s to mid 80s.

Monday...Continued mild as the flow aloft backs to southwest. With some low and mid level moisture, we may see isolated to widely scattered late day showers.

Tuesday...As a shortwave trough aloft and its associated cold front pass by the forecast area, high temperatures will decrease into the 60s to lower 70s. Looks like enough low and mid level moisture to combine with frontal lifting to produce scattered showers, most numerous near the Colorado state line.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 525 PM MDT Tue Mar 24 2026

VFR conditions will prevail across all terminals for the duration of this TAF period. Winds this afternoon/evening will be on the downward trend for most sites except KLAR and KRWL, where westerly gusts 25 to 35 knots will persist for this entire forecast period. The other sites, winds will ramp right back up by 20Z Wednesday with gusts 20 to 25 knots. KAIA will escape the gustier winds as winds will remain in the 5 to 15 knot range.

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 Warning until 3 PM MDT Wednesday for WYZ110. High Wind Warning until 9 PM MDT this evening for WYZ116. NE...Red Flag Warning from 11 AM to 10 PM MDT Wednesday for NEZ434>437.