Area Forecast Discussion
Issued by NWS Riverton, WY
Issued by NWS Riverton, WY
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770 FXUS65 KRIW 140446 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 1046 PM MDT Fri Sep 13 2024 .KEY MESSAGES... - Warmer and drier conditions through Saturday with little precipitation expected. - Dry and gusty conditions will lead to critical fire weather conditions across portions of central Wyoming Saturday afternoon. - Precipitation chances increase Sunday across the west, then everywhere Monday and Tuesday as a system approaches. - An active pattern is favored through next week which may lead to cooler and wetter conditions. && .DISCUSSION... Issued at 203 PM MDT Fri Sep 13 2024 Today is a weather transition day behind yesterday`s low and associated cold front. Temperatures will peak 4 to 8 degrees below normal, with skies remaining mostly clear. The only exception may be across the northwestern mountains where an isolated shower may pop up within the westerly flow there. Warmer and drier conditions will continue on Saturday as a near zonal west flow sets up over Wyoming. Near to above normal high temperatures will return, generally peaking in the 70s or low 80s across lower elevations. Skies will remain mostly clear with only a low chance of an isolated shower or two across far northern Wyoming. One weather concern we will have Saturday is fire weather as a fairly weak surface low develops across eastern Wyoming. In response, this will make for a gusty (but not unusual) day across portions of central Wyoming. We will be upgrading to a Red Flag Warning for a few fire zones given the wind and low humidity expected there. By Sunday the predominant flow becomes southwesterly as a low pressure system begins pushing into the Pacific Northwest. This will advect even warmer air into the area, bringing highs 5 to 10 degrees above normal. This will also return more moisture to the area; isolated showers are possible in the afternoon across the western third of the area (PoPs generally <20 percent). East of the Divide will remain dry, and additional fire weather highlights may need to be considered if the southwesterly wind continues to trend up. Precipitation chances will increase Sunday evening, still mostly limited to western Wyoming. Southerly flow will take over Monday and Tuesday as the previously mentioned low drops south and then approaches Wyoming. This will spread precipitation chances eastward through Tuesday, though once again most focused on western Wyoming as the low stays centered over Idaho as it pulls north. Temperatures are looking cooler on Tuesday as a cold front sweeps across the area. Further ahead, guidance continues to favor another system swinging through by Wednesday or Thursday. As it stands now this would track a little farther east than the previous system with the low passing right over Wyoming. Though solutions remain uncertain, this would favor cooler than normal temperatures and a better chance for a widespread wetting rain in the latter half of the week. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 1046 PM MDT Fri Sep 13 2024 Prevailing VFR conditions to persist through the TAF period as the region remains in between weather systems through Saturday. Wind will be the only weather hazard, but will not be very strong for most terminals, with gusts of 10-20 knots Saturday afternoon. The exception is KCPR where wind will be around 15 knots, with gusts of 20-30 knots, Saturday afternoon. Skies will be mostly clear for the next 24 hours. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on icing and turbulence forecasts. && .FIRE WEATHER... Issued at 203 PM MDT Fri Sep 13 2024 A building surface pressure gradient will lead to elevated to critical fire weather conditions Saturday afternoon across much of central and southern Wyoming. The Fire Weather Watch will be upgraded to a Red Flag Warning where the wind and low humidity align. Sunday is also looking dry and gusty as steering flow becomes southwesterly. Additional fire weather highlights may be needed again for portions of central Wyoming, though humidity remaining slightly elevated may keep the concern fairly limited. && .RIW WATCHES/WARNINGS/ADVISORIES... Red Flag Warning from noon to 7 PM MDT Saturday for WYZ280-289- 300. && $$ DISCUSSION...Myers AVIATION...Rowe FIRE WEATHER...Myers