004 FXUS65 KRIW 140448 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 1048 PM MDT Sun Apr 13 2025 .KEY MESSAGES... - A return of seasonable temperatures to the region through Monday after a period of recording breaking warmth. - Warm above normal temperatures return for the middle of the upcoming week with an increasing likelihood for a disturbance moving through the area by the second half of the week. && .UPDATE... Issued at 1233 PM MDT Sun Apr 13 2025 Seasonable temperatures have returned to the Cowboy State today. Highs across the area will be in the low 50s east of the Divide and 40s west of the Divide. Strong gusty winds are the main concern today mainly across Johnson County where High Wind Warnings are in effect through Sunday evening. Periodic gusts exceeding 55 mph will be possible across Johnson County this afternoon and evening. The remainder of the state will see breezy winds with occasional gusts of 15 to 25 mph. Winds diminish shortly after sunset becoming light for the overnight. The rest of the forecast remains mostly unchanged with high pressure building in for the first half of the week. Warm temperatures are expected to return to the region with highs well above normal for Tuesday and Wednesday. Regarding the second half of the week there continues to be uncertainty in term of the forecast. Long range models continue to show a disturbance moving through the region by Thursday. Overall, there is a general consensus of some disturbance developing and moving across the western CONUS. However, the track of this disturbance, the timing, and the impacts still are uncertain. As of writing this on Sunday there does look to be a trend towards some impacts to the state whether it will be isolated or widespread is still to be determined. && .DISCUSSION... Issued at 141 AM MDT Sun Apr 13 2025 Tonight, we are listening to a Top 40 countdown of 80s hits. And keeping with the 80s theme, the weather pattern reminds me of an 80s song that was a staple of early MTV over 40 years ago, where did the time go? It is by John Waite, who is best known for the song "Missing You." But the song I am thinking of is "Change" (its a good song, look it up). It describes the weather pattern for the week, and is very common for Wyoming this time of year. The cold front that brought the showers and storms yesterday is now moving east of the area, and has brought in some much colder air, this is a change definitely. Temperatures will average 20 to 30 degrees colder than on Friday, when there were many record highs and some locations had the earliest 80 degree temperature in station history. In addition to this, a gusty to strong wind will continue, making it feel even cooler and a slap in the face after the nice weather of a few days ago. The main offender for the wind is a low moving across Montana, setting up a tight pressure gradient with an area of high pressure over Idaho. We have a good setup for high wind across northern Johnson County as a result. We will have a northwest flow / cold advection pattern across the region. In addition, the area will be in the left rear quadrant of the jet, enhancing downward forcing. On the probabilistic side of things, the NBM ensemble is showing a 3 out of 4 chance of wind gusts past 60 mph over northern Johnson County. As a result, we have issued a High Wind Warning starting at 9 am this morning and continuing through 6 pm. We thought about Big Horn County as well, but here chances are less than 1 out of 2 so we decided against it, but it will be fairly windy though. Many areas will see a gusty breeze through the day as well, before decreasing after sunset as the atmosphere decouples. In addition, elevated fire weather conditions will be possible this afternoon, although cooler temperatures should lessen the impact somewhat. As for precipitation, we could see a few instability showers, but these would be few and far between. The exception may be the western slopes of the Bighorns, where upslope flow with the flow around the low should keep some snow showers going through the day. The next change will be some quieter weather. High pressure will bring dry weather from later tonight through most of Wednesday. Monday still looks cool with some breezes continuing in Johnson County. Tuesday looks like the nicest day of the period with a good deal of sunshine, comfortably warm temperatures and only somewhat of a breeze, one of those really nice Spring days that are precious in this neck of the woods. Wind will increase a bit on Wednesday as the next weather system, an upper level low dropping out of Canada, moves toward the area. The latest model runs are slower, so Wednesday could end up being mainly dry. From Thursday into next weekend, the forecast is, to put it mildly, in flux. This system is very complex with a lot of spokes of energy rotating around it, and upper level lows are notoriously fickle with movement. There is also little consistency from run to run. So the reasoning today remains the same as yesterday, we have high confidence in a cooler and more unsettled pattern late next week, but details at this point are still highly uncertain. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 1046 PM MDT Sun Apr 13 2025 VFR conditions will prevail through the period as high pressure returns to Wyoming. Wind will be light overnight before increasing mid-Monday morning for several terminals, though generally remaining below 15 knots. KCPR will be the exception, with northwest winds gusting to 25 knots through the afternoon. Otherwise, skies will remain clear at all terminals. 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. && $$ UPDATE...Dziewaltowski DISCUSSION...Hattings AVIATION...Myers