Area Forecast Discussion
Issued by NWS Riverton, WY

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000 FXUS65 KRIW 222340 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 540 PM MDT Thu Apr 22 2021 .SHORT TERM...This evening through Friday night Issued at 248 PM MDT Thu Apr 22 2021 The next cold front is on the doorstep of northwest WY this afternoon, and should be sweeping across the state through the night tonight. There is enough cold air and lift associated with and behind the front that some snow accumulations are still expected for the northern mountain ranges, generally reaching 1 to 4 inches by Monday evening. Any precipitation reaching the lower valley floors will likely remain as rain through Friday morning, mainly for the Big Horn Basin. The cold pool behind the front generally remains east of the Divide tomorrow, so those areas will struggle to get out of the 40s, while southern WY gets into the 50s with better cloud breaks. .LONG TERM...Saturday through Thursday Issued at 248 PM MDT Thu Apr 22 2021 The long-term starts off on Saturday with some ridging over the Cowboy State at 12Z. The next system from the west looks to start impacting far western areas as early as 18Z Saturday. The main story from then through Monday is precipitation over for areas west of the Divide, as the trough near the West Coast starts to amplify. For areas west of the Divide, liquid amounts look to be on the order of around .5 to .75 inches with some areas near the Idaho border possibly having close to an inch. Temperatures at 700mb range between 0C to -4C, so probably much of the precipitation would be in the form of rain or a mix or rain and snow with some light accumulations possibly mainly at night. Further shifts can pinpoint if snow looks to be significant, but at this point it does not seem to be a big factor. For areas east of the Divide, expect seasonal high temperatures and dry conditions for both days of the weekend, except in the Bighorns. By Monday afternoon into Tuesday, the moisture finally starts pushing east of the Divide, but liquid amounts are expected to be much less (more in the area of around a quarter of an inch). While temperatures look to be quite a bit cooler east of the Divide for Monday and Tuesday, rain looks more likely in these areas. Models diverge a good bit starting Wednesday, but overall it looks like dry conditions with a ridge and high temperatures moving back to near or above normal by the end of the period. && .AVIATION...For the 00Z TAFS through 00Z Saturday Expect VFR conditions to prevail throughout the TAF period for most of the terminals. A cold front is expected to start impacting northern areas with some VCSH at the start of the TAF period. These showers will change over to snow by 03Z and mainly impact KCOD and KWRL. MVFR conditions will be possible at KCOD by 12Z, as snow moves over the area. Precipitation will become confined over the northern mountains by 18Z, with breaks in the clouds in the afternoon. Gusty winds will return to KBPI, KPNA and KRKS by 18Z. 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 248 PM MDT Thu Apr 22 2021 A cold front will move across the state tonight and tomorrow, bringing another round of light rain and snow to northern WY. Winds behind the front are not expected to be gusty, so overall mixing and dispersal remain fair through the rest of the week. && .RIW WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Straub LONG TERM...Clayton AVIATION...Clayton FIRE WEATHER...Straub is the U.S. government's official web portal to all federal, state and local government web resources and services.