textproduct: Cheyenne

KEY MESSAGES

- A few strong to severe thunderstorms are possible Wednesday and Thursday.

- Above average temperatures are expected to persist through the upcoming weekend.

- Daily chances for afternoon showers and thunderstorms will continue through early next week.

SHORT TERM /THROUGH THURSDAY NIGHT/

Issued at 420 PM MDT Tue Jun 10 2025

The pocket of dry air that suppressed all convection yesterday is drifting eastward across Nebraska as apparent on GOES water vapor imagery this afternoon. The axis of a stronger ridge is now setting up over the Rockies, with several disorganized vort-maxes continuing to rotate over the top of the feature. Typical diurnal cumulus clouds have developed over much of southeast Wyoming, but limited instability and minimal shear are preventing thunder so far. Forcing will increase as we head into the evening hours, leading to increased shower coverage and a higher probability for a few rumbles of thunder. This activity will have the potential to produce some locally gusty and erratic winds well into the evening hours, but severe winds are fairly unlikely.

A weak back door cool front will drift into the High Plains overnight and bring weak upslope winds, higher dewpoints, and more cloud cover to start our Wednesday. Expect highs to be a few degrees cooler than today as a result. Synoptic forcing will increase once again in the late afternoon and evening hours as a more organized upper level shortwave moves in from the west. Vertical wind shear will be higher than today, but still fairly marginal. However, lapse rates look quite steep with decent instability present. Southeast Wyoming looks fairly uncapped by midday, but there will be quite a bit of CIN present over the Nebraska panhandle. Expect the first round of widely scattered showers and thunderstorms to initiate over the higher terrain in the early afternoon hours (or perhaps even late morning) and drift eastward through the afternoon. The best potential for strong to severe thunderstorms will be over Converse, Niobrara, Platte, and Goshen counties, but it would not be surprising to see the marginal risk expand slightly southward and eastward. Gusty winds will be the primary threat, but isolated large hail cannot be ruled out. A second round of widely scattered showers and thunderstorms will move across the area during the evening along the upper level shortwave trough axis, beginning in Carbon county around 6PM and reaching Chadron around midnight. This may bring a more organized round of strong winds, but confidence is low in the speeds it will be capable of producing at the surface.

Typical early summer weather will carry us into Thursday with warm to hot temperatures and another chance for afternoon and evening showers and thunderstorms for the area. Forcing looks a little weaker on Thursday, but still present with another weak vort-max riding over the top of the upper level ridge. Still, forecast soundings support the possibility for a few marginally strong to severe thunderstorms once again.

LONG TERM /FRIDAY THROUGH MONDAY/

Issued at 420 PM MDT Tue Jun 10 2025

Friday...A weak low amplitude ridge aloft prevails, though with a cold frontal boundary across our eastern counties, and adequate moisture, we should again see isolated to widely scattered showers and thunderstorms in the afternoon and evening, mainly east of I-25.

Saturday-Sunday...Ridging aloft prevails and with 700 mb temperatures near 14-18 Celsius producing warm temperatures aloft and convective inhibition, only widely scattered evening showers and thunderstorms look possible east of a Lusk to Kimball line. High temperatures in the mid 80s to lower 90s.

Monday...A weak cold frontal passage will drop maximum temperatures back into the lower to mid 80s. Adequate low and mid level moisture will help produce scattered late day showers and thunderstorms east of I-25.

Tuesday...With zonal flow aloft and adequate moisture, we expect an increase in cloud cover and shower and thunderstorm coverage, and thus somewhat cooler temperatures.

AVIATION /06Z TAFS THROUGH 12Z THURSDAY/

Issued at 1135 PM MDT Tue Jun 10 2025

A slow moving cold front will gradually push south across the eastern plains late this evening and overnight. Another round of thunderstorms are expected along and near this front Wednesday afternoon through Wednesday evening for all SE Wyoming and western NE terminals.

HAZARDS/WEATHER TRENDS: A cluster of thunderstorms is forecast to impact KCDR over the next 2 to 3 hours, or until 09z. Could be some brief MVFR VIS in moderate rain. Otherwise, VFR conditions are expected for all other terminals through 18z Wednesday as surface winds shift into the north or northwest behind a surface cold front.

Cold front is expected to stall Wednesday afternoon, leading to another round of showers and thunderstorms. Expect overall coverage to be greater compared to Tuesday, so added TS to most terminals. Brief heavy rain, gusty winds, and frequent lightning will be the primary threats with these thunderstorms through 06z Thursday.

CYS WATCHES/WARNINGS/ADVISORIES

WY...None. NE...None.