textproduct: Cheyenne

KEY MESSAGES

- Elevated fire weather conditions will continue for much of the week ahead. Red Flag Warnings in effect east of the Laramie Range for Tuesday afternoon.

- Scattered thunderstorms late Tuesday evening will have the potential to become strong to severe, mainly in the central and southern Nebraska panhandle.

SHORT TERM /THROUGH WEDNESDAY NIGHT/

Issued at 245 AM MDT Tue Jun 30 2026

A mixture of both fire weather and scattered showers and thunderstorms will be possible today as an upper-level shortwave traverses the CWA. Ahead of the shortwave, dry air will exist in the low and mid-levels, leading to low relative humidity at the surface for most of the forecast area. With the incoming shortwave, an increase in wind is also expected. The combination of dry and breezy conditions will produce elevated to near critical fire weather concerns. This will primarily be for areas east of the Laramie Range where fuels are deemed dry and critical. As a result, Red Flag Warnings have been issued for this area for Tuesday afternoon. Humidity will begin to increase later in the afternoon as precipitation chances also increase. With the shortwave expected to enter the CWA this evening, storms will likely get a later start, with development by late afternoon. Hi-Res guidance shows scattered showers and storms continuing through about midnight, with a few lingering showers possible after that. Model soundings actually show a good amount of instability overnight, allowing storms to continue past sunset. Cannot rule out an isolated strong to severe storm or two. With the dry surface, model soundings show deeply inverted-V profiles. This will lead to elevated DCAPE values in excess of 900 J/kg for most locations east of the Laramie Range. DCAPE values of this magnitude could lead to severe wind gusts in any storms that develop. Cannot rule out large hail in storms, however, MUCAPE values are not as impressive.

Looking at a fairly benign day on Wednesday with temperatures similar to Tuesday. Highs will be in the 70s and 80s with mostly sunny skies. Another dry day is expected as more dry air aloft moves in behind the shortwave. Relative humidity with be in the low teens, however, wind will be a limiting factor in any critical fire weather conditions. Cannot rule out a slight chance of showers Wednesday evening, however it will likely be too dry for much, if any, precipitation to reach the ground.

LONG TERM /THURSDAY THROUGH MONDAY/

Issued at 303 PM MDT Mon Jun 29 2026

As we progress past Tuesday, we become stuck in Southwest flow on the front side of this ridge. The warm, dry, but smokey air from the Desert southwest and the Colorado/Utah fires will be filtering over the area for the remainder of the week. This will limit our rain chances as this dry air removes all the moisture from the surface and lower dewpoints and RH values. The models have a few shortwaves pushing into the region past Tuesday but with no moisture and very limited forcing there isn't much confidence these waves will do anything beside increase our gradient and produce the normal amount of wind through our area. Fire weather will be the biggest concern as our fuels will enter a curing state once again despite our stormy 7 days last week. Winds will be light to marginal so it may be difficult to reach Red Flag criteria for most of our area despite the low RH and curing fuels. There is another trough that may move through Friday night into Saturday morning for a possibly wet start to our 4th of July weekend plans. Looking at the global models, each one has a different intensity of forcing but there is a general uptick by the models compared to yesterday. While it still doesn't look to be a strong four corner low, the shortwave trough may be strong enough to overcome the dry air and give us some measurable precipitation. Given it is the 4th of July, we will be monitoring this set up closely and try to narrow down timing and locations for everyone.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 534 AM MDT Tue Jun 30 2026

Mostly sunny skies are expected through much of the day at terminals across southeast Wyoming and western Nebraska. Smoke will be possible aloft from wildfires, but should not cause significant visibility drops at the surface. Showers and thunderstorms will develop late this afternoon and continue through much of the night. Gusty winds and hail will be the main concern in storms, with moderate rain also possible.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Red Flag Warning from 11 AM this morning to 7 PM MDT this evening for WYZ417-418-430>433. NE...Red Flag Warning from 11 AM this morning to 7 PM MDT this evening for NEZ434>437.