Area Forecast Discussion
Issued by NWS Riverton, WY
Issued by NWS Riverton, WY
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608 FXUS65 KRIW 012342 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 542 PM MDT Mon Jul 1 2024 .KEY MESSAGES... - Marginal (Level 1 of 5) Risk of severe thunderstorms across north-central Wyoming through this evening. Large hail, strong winds, and frequent lightning are the primary concerns in the strongest storms. - Continued cooler temperatures and increased precipitation chances through mid-week across northern Wyoming. - Warm, dry, and breezy conditions expected across south-central and southwest Wyoming through the next week. Elevated to critical fire weather conditions in areas with cured fuels. && .DISCUSSION... Issued at 150 PM MDT Mon Jul 1 2024 As the cold front is draped across Wyoming, rain showers and thunderstorms have been observed, as well as wind gusts along and behind the front of 30 to 40 mph, even higher in wind prone areas and from thunderstorm outflow. While the main shower and thunderstorm activity will be up in north-central Wyoming, a few showers and weak thunderstorms cannot be ruled out near the I-80 corridor east of Rock Springs. Up in north-central Wyoming there is a Marginal Risk for severe thunderstorms where HiRes guidance is showing 500-1000 J/kg of SBCAPE and 35-45 knots of bulk shear, which is substantial to sustain convection. Based on the latest HiRes model runs, the most likely time frame for the strongest storms in north-central Wyoming is from 2 PM to 6 PM. Showers will linger overnight and through Tuesday morning as another shortwave pushes through northern Wyoming. While there is still the potential for thunderstorms Tuesday, the severe parameters are much more limited, especially the instability, so any thunderstorms that do develop will likely not be severe. The main shower and thunderstorm activity will decrease through Tuesday evening. Headed into the Independence Day holiday, the Riverton forecast area is positioned along the east side of an upper-level ridge as multiple shortwaves are embedded in the flow. This will help moderate temperatures and keep them, on average, near-normal. In addition, there are chances for showers and thunderstorm each afternoon through Thursday, particularly across the northern half of Wyoming. Across the High Desert Region, warm temperatures, low afternoon relative humidity values, and gusty winds will create critical fire weather conditions where the fuels are cured and ready to burn. Due to the timing of these conditions being near the 4th of July, caution is recommended if opting to participate in the festivities. Following the shortwave passage on the 4th of July, the upper-level ridge shifts eastward, increasing temperatures and decreasing precipitation chances headed into the weekend. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 542 PM MDT Mon Jul 1 2024 Scattered showers and thunderstorms continue through the evening across the northern-third of Wyoming. KJAC, KCOD, and KWRL have the best chance of seeing convection through 04Z/Tuesday. Terminals remain VFR with the exception of brief MVFR with the strongest convection, while brief IFR remains a 20-30 percent possibility. Gusty westerly surface wind 20-30kts continues until sunset at KRKS. To the north, thunderstorm outflow will send wind to the north at the central terminals early Monday evening. Moisture continues to wrap into the far north overnight with light showers persisting. Additional showers linger this evening from around KRKS to KCPR with gusty outflow wind of 40kts the primary hazard. After a quiet Tuesday morning, a few late day showers are possible across the north. In general, Tuesday finds conditions VFR and generally dry. 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. && $$ DISCUSSION...Gross AVIATION...CNJ