


Area Forecast Discussion
Issued by NWS Riverton, WY
Issued by NWS Riverton, WY
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622 FXUS65 KRIW 112309 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 509 PM MDT Fri Jul 11 2025 .KEY MESSAGES... - A brief relief from the recent summer heat across the Cowboy State today. - Isolated to scattered showers and thunderstorms are expected to develop this afternoon and evening. A few strong to severe thunderstorms may be possible. - Hot and dry conditions return for the weekend into the start of next week with the potential for fire weather conditions by Monday. && .UPDATE... Issued at 1236 PM MDT Fri Jul 11 2025 A cold front has moved across much of the Cowboy State overnight. The frontal passage has brought relief to the recent heat that enveloped the region over the past week. Highs today will reflect this relief with temperatures in the mid to upper 70s east of the Divide and upper 70s to low 80s west of the Divide. Scattered showers and isolated thunderstorms moved across northern WY this morning but have now dissipated. Another round of showers and thunderstorms is expected to develop this afternoon. The best chances of seeing a shower or thunderstorm look to be east of the Divide, especially across central WY. CAMs have highlighted portions of the Wind River Basin, eastern Sweetwater County and southern Natrona County. Overall, dynamics are not overly impressive but there does look to be some favorable components that may lead to a strong or near severe storm. CAPE values are marginal ranging from 500 to 1000 J/kg with some shear present but not overly impressive. PWAT values look to be above normal with values ranging from 0.75 to 1.00 in. These dynamics will lead to the possibility of a few hazards as a result of any strong storms that develop. These hazards look to be hail, strong gusty outflow winds, and isolated heavy downpours. Very isolated flash flooding cannot be ruled out, especially in poor drainage locations but the overall concern for this is not very high. As mentioned earlier, CAMs highlight central WY especially portions of the Wind River Basin. SPC`s day 1 outlook supports this with a sliver of marginal chances for severe thunderstorms being drawn across central WY into southwestern WY. Showers and thunderstorms look to start developing shortly after noon over northern WY and gradually tracking southeast through the remainder of the afternoon and evening. Convection moves out of the area around sunset with quiet weather prevailing overnight through the weekend. The weekend sees warmer and drier conditions return to the area with highs reaching the upper 80s to mid 90s. These warm temperatures and dry conditions may lead to fire concerns by Monday. Winds are looking to increase Monday along with low min RH values and warm temperatures. These components may lead to portions of the state seeing elevated to near critical fire weather conditions. This possibility will continue to be monitored as we head into the weekend. The next chance for precipitation does not look to arrive until the start of next week as a trough moves across the region. Another front moves through the area around Tuesday night bringing in a brief period of cooler temperatures. The remainder of the week looks to have increased chances for precipitation as multiple disturbances move through the region. && .DISCUSSION... Issued at 259 AM MDT Fri Jul 11 2025 When I was surfing the net before I left for work, I happened upon an old commercial I have not seen since my youth, many eons ago. It is for the antacid Rolaids. And the question asked in it is: How do you spell relief? And the answer is spelled out: R-O-L-A-I-D-S. And this relates to this question, how do you spell relief from the heat? And the answer is C-O-L-D F-R-O-N-T. A cold front is currently moving through the area, having passed through the humble Riverton weather abode a bit ago with wind gusts close to 50 mph with the strong cold advection. Both Greybull and Buffalo have gusted over 50 mph as well. These strong wind gusts should slowly end though. The big change today will be much cooler temperatures that will move in today East of the Divide, where some locations will be up to 20 degrees cooler than yesterday, with a place like Buffalo struggling to get out of the 60s. It will feel more like May than July. It will remain warm West of the Divide though, with temperatures close to yesterday`s highs though. As for convection, we do have some instability but not a ton, maximum CAPE values max out at around 1000 J/Kg in some of the mountains but it is generally around 500 J/Kg or less. Lifted indices generally drop down as low as minus 2. Much of the area, except for southwestern Wyoming, may see a shower or storm but the chance is generally at most 1 out of 4, with up to a 2 in 5 chance in some of the mountain ranges. Most of this looks like an early show, with most over around 6 pm and all over by sunset. The weekend at this point looks relatively uneventful with mainly dry conditions under northwest flow. Many people will be suffering from temperature whiplash though with near to above normal highs returning Saturday and especially Sunday with widespread 90s in the lower elevations East of the Divide and some locations getting close to 100. Fire weather concerns look low though with wind remaining light to moderate. Active weather then begins ramping up again starting Monday. On Monday a shortwave will approach the area and bring a chance of showers and storms, mainly across northern portions of the state. This will also tighten the pressure gradient across the area and bring a gusty wind which will likely increase fire weather concerns, especially in southern Wyoming. Following that, a more potent cold front will drop southward into the area and bring a better chance of showers and storms, possibly both on Tuesday and into Wednesday. Details on which day will be wetter and details of where the storms may fire are still highly uncertain though. Cooler temperatures will also move in for midweek as a trough lingers across the area. So, it looks like we will be riding the temperature rollercoaster as we head into through the middle of July. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 508 PM MDT Fri Jul 11 2025 Showers and thunderstorms impacting east of the Divide terminals to start the period will quickly exit from west to east by 02 to 03Z. Skies quickly clear after 05Z, with light winds and mostly SKC prevailing through Saturday morning. KRKS will see the gusty northeast winds continue a bit longer, expected to drop off around 07Z. Terminals east of the Divide will see winds less than 10kt continue through the end of the period, while west of the Divide terminals will see winds start to tick up around 18Z with gusts 15 to 20kts expected through the afternoon on Saturday. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on smoke, icing, and turbulence forecasts. && .RIW WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Dziewaltowski DISCUSSION...Hattings AVIATION...Hensley