Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
492 FXUS65 KBOI 130322 AFDBOI Area Forecast Discussion National Weather Service Boise ID 922 PM MDT Sun May 12 2024 .DISCUSSION...Showers and thunderstorms have developed across Harney County this evening and are slowly tracking to the east. Wind gusts to 45 mph are possible from thunderstorms through sunset. They`re forming ahead of a shortwave trough that pushing onto the Pac NW and will move across the area on Monday. The upper level dynamics associated with this wave will keep a low chance of showers overnight across SE Oregon and into early Monday morning for portions of SW Idaho. Have updated forecast to introduce a 15% chance of showers over the lower Treasure Valley and Owyhee mtns for early Monday morning. There remains a chance for Auroral activity tonight across SE Oregon and SW Idaho. There are areas of cloud cover across the region tonight, the most extensive associated with the showers and thunderstorms over SE Oregon. The best chance for clear skies will be early in the night. && .AVIATION...VFR. Showers across SE Oregon tonight, with isolated thunderstorms through 06Z. Isolated showers and thunderstorms across mtns of SW Idaho and western Magic Valley on Monday. Surface winds: less than 10 kt overnight, increasing to 10-20 kt with local gusts to 25 kt on Monday. Winds at 10kft MSL: W 10-20 kt. KBOI...VFR. Surface winds: less than 10 kt through Monday morning, increasing out of the NW Monday afternoon. && .PREV DISCUSSION... SHORT TERM...Tonight through Monday night...A shortwave trough will approach our area tonight. Enough moisture and instability will exist for isolated shower and thunderstorm development across southeast Oregon this evening before weakening overnight. Dry surface conditions will result in gusty outflow winds near thunderstorms. A 5-10% chance of showers will persist overnight, with clouds increasing across southwest Idaho as the system moves east. The trough axis and weak cold front will cross our area Monday afternoon. A few showers will develop Monday morning, but most shower and thunderstorm activity will take place Monday afternoon and early evening. Most of the showers and storms will develop across the central Idaho mountains and near the Nevada border where daytime instability will be greatest. Temperatures will be a few degrees cooler, but still nearly 10 degrees above normal. Winds will be breezy behind the front. LONG TERM...Tuesday through Sunday...An upper level ridge will remain centered over the eastern Pacific on Tuesday while a shortwave trough drops south along the east side of the ridge on Tuesday. The shortwave trough will move through the northern Rockies and clip our area causing the ridge to retreat slightly westward. This will produce a 5-15% chance of showers and thunderstorms across central Idaho with dry conditions elsewhere. Northwesterly flow will cool temperatures a few degrees, and the trough will produce breezy conditions, especially across south- central Idaho. The ridge will rebuild eastward again on Wednesday, bringing dry and slightly warmer conditions through Thursday. Model Ensembles are hinting that another stronger shortwave trough will push the ridge back toward the west again by Friday or Saturday. If this pattern shift occurs as most models are now showing, temperatures to cool a bit and the chance of precipitation will increase for the upcoming weekend. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.twitter.com/NWSBoise DISCUSSION...DG AVIATION.....DG SHORT TERM...ST LONG TERM....JB