Area Forecast Discussion
Issued by NWS Riverton, WY
Issued by NWS Riverton, WY
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551 FXUS65 KRIW 291737 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 1137 AM MDT Wed May 29 2024 .KEY MESSAGES... - A weather system brings more widespread rain shower and thunderstorm chances to the area today. It will also be breezy across the area. - The end of the week looks dry and a bit cooler after the system passes on Wednesday. Then, slight chances for thunderstorms on Saturday and Sunday. - Monday looks hot and dry once again before another shortwave clips the area on Tuesday, with more rain shower/thunderstorm chances. - Long-range model guidance continues to indicate a hot and dry period beginning late next week as a dominant ridge sets up over the western US. && .DISCUSSION... Issued at 316 AM MDT Wed May 29 2024 A more meaningful shortwave will pass through today, with more widespread rain showers and thunderstorms this afternoon/evening. The SPC has upgraded northern portions of the State to a Marginal risk for severe weather this afternoon. The only threats are strong to damaging wind gusts and frequent lightning, but small hail is possible (40%) as well. This shortwave will bring breezy conditions today. Temperatures will be about 10 degrees cooler across northwestern portions of the area due to increased cloud cover and rain, elsewhere temperatures will be similar to Tuesday. A Rangeland Fire Danger Statement has been issued for this afternoon due to the breezy wind, low RH, and warm temperatures. After this system moves through it will be warm and mostly dry through Friday. Another slight chance (20-30%) of rain showers/thunderstorms this weekend as another quick moving shortwave will slide through the Cowboy State. Minor river flooding is possible (30-40%) through tonight due to mountain snowmelt as temperatures remain warm today, but as it stands right now all rivers are behaving. Overall, it will be an unsettled weather pattern with shortwaves in mostly zonal flow through this weekend into next week. The shortwaves will all be quick moving and weak, so not expecting big precip makers or highly impactful weather into next week. It will be fairly breezy for most locations beginning today and continuing into next week. The breezy conditions, combined with low RH will lead to elevated fire weather conditions later this week through this weekend, although greenup will limit this threat. The amplified ridge that model guidance was indicating for next week now looks like it will develop a bit later as another trough slides through on Tuesday. Regardless of the active pattern temperatures will not drop all that much as each trough/shortwave should stay north as they pass through the region. && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 1136 AM MDT Wed May 29 2024 A weak shortwave will pass through the region today. With it, varying chances for showers and thunderstorms will exist across the region today. Light winds to start the period will increase through the afternoon for most terminals. Shower and thunderstorm chances will generally move west to east through the period. TEMPO groups have been included to cover the most likely period of thunderstorms at each terminal. With the thunderstorms, gusty and erratic outflow winds are expected. Locally strong gusts up to 40kts are possible with stronger storms (20% chance). After 06Z, showers and thunderstorms are no longer expected, with VFR prevailing at all terminals. East of the Divide terminals will see a light northerly wind push behind the showers and thunderstorms overnight, which will decrease and become light by around 06Z. Winds also generally become light and variable overnight for most other terminals. Models are hinting at low clouds (as a result of moist, weak northerly surface flow) at KCPR overnight. Have left VFR for now, but there is a 50% chance of MVFR cigs and a 30% chance of IFR cigs developing between 06Z and 09Z at KCPR. These cigs will scatter out Thursday morning, between 13Z and 16Z. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on icing and turbulence forecasts. && .RIW WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Rowe AVIATION...Hensley