Plaincast

Messages

Isolated showers and thunderstorms continue this evening and will subside after sunset. A few thunderstorms could be strong, with locally gusty winds around 50 mph, mainly over the northwest- quadrant of the state.

More scattered showers and storms will develop across the area Sunday afternoon. Again, locally gusty wind around 50 mph will be possible.

Areas away from showers and thunderstorms will be hot Sunday, with highs in the 90s and low 100s. Heat Advisories are in effect for the basins of central and northern Wyoming Sunday.

Above normal temperatures continue through the upcoming week, with highs each afternoon in the 90s. Monsoon moisture remains in place, producing afternoon and evening showers and thunderstorms through at least Wednesday.

Update

Morning showers associated with a passing shortwave are about to exit Johnson County late Saturday morning, while cumulus development is already underway over southwest Wyoming. Despite a deep-mixed layer and wide temperature-dewpoint spreads Saturday afternoon, there is still plenty of mid-level moisture in southwest flow aloft to generate scattered showers and thunderstorms. The inverted-V profiles lead to the main hazard being gusty outflow wind 40 to 50 mph from even weak convection. Most convection wanes between 7 and 9 PM Saturday, although recent CAMS runs show lingering weak convection over central Wyoming through Saturday evening. Over far northwest Wyoming, a favorable plume of mid-level moisture lingers until early Sunday morning leading to isolated light showers. This same area receives another punch of moisture late Sunday morning leading to earlier convective development during the midday hours across this region. A Heat Advisory continues through Sunday for basins east of the Continental Divide as temperatures hover 8 to 12 degrees above normal. The heat and associated low relative humidity leads to elevated fire weather conditions Saturday afternoon, especially in Natrona and Johnson Counties.

Discussion

Not much pattern change expected during the next week, as the H5 ridge remains firmly anchored on the Four Corners. This will keep very warm temperatures in place across most of the state, with highs each afternoon in the 90s. Today will be the warmest of these days, with some 100 degree readings for the Bighorn Basin and along the I-25 corridor.

Even with the ridge holding hot temperatures in place, the placement of the ridge will still allow monsoon moisture to draw northeast into the western half of the state. This will bring daily chances for showers and thunderstorms building along the higher elevations of the western mountain ranges, then drifting northeast around the ridge into Montana. Shower chances will be enhanced by any small-scale shortwaves wrapping around the ridge. One of these will sweep through this afternoon across NW Wyoming. Combine this enhancement with higher temperatures today to bring some strong thunderstorms. With dewpoint depressions approaching 50 degrees, very gusty winds would be the main impact, with wind gusts in excess of 50 mph possible. As these storms are moving northeast at a reasonable rate, localized flooding concerns are decreased today. Daytime thunderstorm chances will continue through the week, building during the afternoon before decreasing at sunset.