Area Forecast Discussion
Issued by NWS Riverton, WY
Issued by NWS Riverton, WY
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142 FXUS65 KRIW 022309 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 509 PM MDT Tue Jul 2 2024 .KEY MESSAGES... - An unsettled weather pattern continues through this week as a trough remains over the region. - Scattered rain showers and thunderstorms will develop across northern Wyoming Wednesday afternoon. Isolated large hail will be possible with these storms. Elevated fire weather conditions will occur across southern Wyoming at the same time. - The weather pattern favors breezy to windy conditions for the next 7 days and mostly dry conditions beyond Thursday. && .DISCUSSION... Issued at 347 PM MDT Tue Jul 2 2024 Troughing will be the general weather pattern through this weekend, with several waves within the trough sliding through Wyoming. Today could be called the calm before the storm in some regards as the flow is mostly zonal behind the wave that passed through the last couple of days. Even so, some isolated thunderstorms have developed. One developed in southern Johnson county earlier today and has since moved into Converse County. There will remain a chance (20-30%) for isolated rain showers and thunderstorms across the northern third of the area through this afternoon. Temperatures are cool this afternoon in the 60s and 70s F. Although temperatures will rise slightly later this week it does not look like a heatwave until (possibly) next week. In fact, Independence Day (The 4th of July) looks very pleasant temperature-wise. The current high temperature forecast is for upper 60s to middle 70s across the area. This is thanks to the wave that will move through Wyoming on Wednesday. The wave on Wednesday will bring a good chance for rain showers and thunderstorms for the northern half of the area. Who gets a good wetting rain with these showers and storms will depend on where they develop, but about from YNP eastward through the Bighorn Basin and into Johnson County is likely to have measurable precipitation from Wednesday through Thursday. Currently, the SPC has a Marginal risk of severe weather in the Bighorn Basin eastward into Johnson County for large hail, which looks like the main threat, but wind is always a threat in Wyoming. Once the wave passes by, the cooler air aloft will allow for isolated convection to develop. The best chance will be along/near the Absaroka Mountains/Bighorn Mountains where afternoon upslope will contribute to lift. Localized heavy rain will be a threat on Thursday, especially in or near the Bighorns as northwest flow sets up and may lead to the formation of some training convection in the Bighorns. PWAT`s don`t look excessive, so not expecting widespread flash flooding. Northwest flow greatly weakens on Friday and this should be a quiet weather day overall. Mostly clear skies on Friday will allow for temperatures to get back to about normal. Model guidance has another wave coming down in northwest flow this weekend, which will bring low chances for isolated convection to mainly northern Wyoming. This looks like the last gasp for the trough that has been sitting over the region as a large amplified ridge pushes into the western US early next week. This ridge will bring hotter temperatures back to Wyoming and heat will become the most impactful weather well into next week based on what long-range model guidance is depicting. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 504 PM MDT Tue Jul 2 2024 VFR conditions dominate the next 24 hours with SCT CU this evening and again tomorrow. Currently one shower passing north of KCOD, but only impacts would be brief gusty NW winds no later than 01Z. Gusty winds return to Wyoming on Wednesday, with gusts 25 to 35kts for all except KJAC and KCOD. Showers and thunderstorms will return to the northern third of the state Wednesday afternoon, impacting KCOD/KGEY/KWRL/KBYG, with a vicinity shower possible as far south as KJAC/KRIW/KCPR. Any thunderstorms would be accompanied by variably gusty winds && .FIRE WEATHER... Issued at 347 PM MDT Tue Jul 2 2024 Elevated fire weather conditions will continue across southern fire zones this week. The worst days will be Wednesday and Saturday as wind increases ahead of weather systems and RH will drop into the teens each afternoon. For northern zones wetting rain is possible (50%) Wednesday afternoon/evening and even into Thursday for The Absarokas Mountains/Bighorn Mountains. Lightning will be frequent with thunderstorms on Wednesday and Thursday, but the storms should have a good amount of moisture with them, so the chance of dry lightning is low (<10%). Smoke dispersal looks to be at least good in the afternoon for the next few days at least. && .RIW WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Rowe AVIATION...Straub FIRE WEATHER...Rowe