Area Forecast Discussion
Issued by NWS Riverton, WY
Issued by NWS Riverton, WY
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807 FXUS65 KRIW 252345 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 545 PM MDT Tue Jun 25 2024 .KEY MESSAGES... - Another hot/dry day today, but cooler than previous days and with less wind. - Better chances for showers and thunderstorms looks to come Wednesday and especially Thursday thanks to a shortwave drawing up Gulf moisture into the region. This should also provide a brief reprieve from the heat. - Ridging, and thus another warming and drying trend will build through the weekend, but we are looking at another shortwave for Monday, which could bring more precip chances and cooler temps. && .DISCUSSION... Issued at 221 PM MDT Tue Jun 25 2024 Slightly cooler today. Many locations are still in the upper 80s as of 100 PM, rather than the 90s that has been the case for the last several days. Winds have been lighter today as well across the region. As expected, convection is fairly weak and very isolated today. Some weak convection stretches across the Green River Basin with a bit of stronger convection that has developed along the state line, but has mainly stayed on the CO side of that line. Our shortwave that will bring some moisture and relief from the heat, currently sits over the Pacific Ocean, well off the coast of WA. This shortwave will begin to push closer to the PACNW tomorrow, and Gulf moisture will begin to be drawn into the ridge. With the Pacific low still off shore, the forcing will not quite be there Wednesday. That being said, there is still a likelihood for convective development, mainly across SW WY and mainly late in the day as the trough pushes onto land. By Thursday, forcing from the shortwave will continue to increase and shower and thunderstorm activity will become more widespread. Focus will remain west of the Divide, especially across the south, however, but there are +/- 10% PoPs across most of the area. PWATs both days are still progged to be around 2 std deviations above normal both Wednesday and Thursday, so heavy rain will continue to be the main threat from stronger thunderstorms. Shower and thunderstorm activity weakens towards sunset Thursday and by Friday, we return to dry weather and mostly sunny skies. Temps Friday will be cooler (low 80s rather than upper 90s), so some relief will be felt despite the dryness. It won`t last long though as the ridge rebuilds for the weekend. Hot, dry, and breezy conditions will exist both Saturday and Sunday. There does look to be another shortwave for Sunday night into Monday, that would provide another break from the heat. This one will not track in Gulf moisture, so heavy rain will not be as likely, but will still see PoPs, mainly across the north. Confidence remains low on details at this time. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 545 PM MDT Tue Jun 25 2024 VFR conditions will continue through tomorrow morning, with daytime high-based cumulus thinning out this evening. Isolated showers and weak thunderstorms persist through sunset south of KRKS along the WY-CO border, and to the northwest of KCOD along the WY-MT border, but these are not expected to impact those locations. On Wednesday morning high cirrus begins to increase. Increased moisture from the southwest will lead to a 20 to 30% chance for showers and perhaps an isolated thunderstorm for sites west of the Divide, as well as KCOD. Have not mentioned this in the TAFs at those sites at this time, given the low likelihood. Locations east of the Divide will likely remain dry, but have a small chance (less than 10%) of a stray shower or thunderstorm. && .RIW WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Hensley AVIATION...VandenBoogart/Straub