Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
119 FXUS65 KBOI 011519 AFDBOI Area Forecast Discussion National Weather Service Boise ID 919 AM MDT Sat Jun 1 2024 .DISCUSSION...No updates to the forecast this morning. A few virga showers have developed in southern Malheur county ahead of a weak upper trough. Isolated shower/virga development will continue throughout the day, with thunder possible in west- central Idaho and far northeast Oregon. Precipitation chances this afternoon/evening are still 10-20% in our area, with the best chances over terrain. Max temps this afternoon will be 5-10 degrees above normal. The upper trough brings a very weak cold front through this evening, allowing winds to stay out of the NW overnight, with gusts 20-25 mph. Sunday will be slightly cooler before a very moist Pacific system arrives Sunday evening. This system will bring steady rain to most of the area, with chances for precipitation between 70-90% from Sunday evening to Monday evening. There is a 20% chance of thunderstorms in SW Idaho Monday afternoon, supported by unstable conditions and abundant moisture. && .AVIATION...VFR with increasing mid and high level clouds today. A slight chance of showers after 18Z, but low confidence (less than 20 percent) in any of the showers reaching terminals. Slight chance (less than 20 percent) of thunderstorms after 18Z in the West Central Mountains (including KMYL). Gusts up to 30 kt with the showers/thunderstorms. Surface winds: W-NW 5-15 kt. 10k ft MSL winds: W 10-20 kt. KBOI...VFR. SE winds less than 10 kt shifting to the northwest after 18Z. Low confidence (less than 20 percent) of a shower after 02/00Z. Sunday Outlook...VFR through Sunday afternoon. High confidence (60- 90 percent chance) of MVFR conditions developing across the north (KBKE-KMYL) associated with widespread rain Sunday night. SW-NW winds 5-15 kt with local gusts to 25 kt. && .PREV DISCUSSION... SHORT TERM...Today through Monday night...Models have been consistently showing marginally moist/unstable support for showers across SE Oregon and SW Idaho this afternoon and evening ahead of a weak upper trough. Confidence is low, therefore pops remain generally less than 20 percent. There is also less than a 20 percent chance of thunderstorms in central Idaho this afternoon. Some of the high resolution guidance indicates wind gusts up to 35 mph with the showers/storms. A weak cold front slides through the region tonight. Wind gusts up to 30 mph accompany the front. Dry conditions in a post-frontal regime are anticipated on Sunday, along with slightly cooler temperatures. A very moist Pacific system is still on track to spread rain across the area Sunday night and Monday. Latest model runs are a bit faster and further south with the heaviest rainfall. Highest total amounts (> 1 inch) are likely (>60 percent chance) across portions of central Idaho, including the Boise/West Central Mountains. There is also a marginal risk for flooding in these areas per latest WPC Outlook, but confidence is low. Forecasts do show some rises on mainstem rivers in central Idaho after the rain event during the midweek, but no forecast points get anywhere close to flood stage. There is also a 20 percent chance of thunderstorms in SW Idaho on Monday. Temperatures will be much cooler, along with breezy to locally windy conditions. LONG TERM...Tuesday through Saturday...Models, including the ensembles, continue to indicate a substantial pattern change to hot/mostly dry conditions later in the week as an upper ridge strengthens over the region. Temperatures warm from near normal on Tuesday to 15-20 degrees above normal Thursday through Saturday. Enough moisture could make it into our area for a slight chance of showers (generally less than 20 percent) late in the week. && .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...JM AVIATION.....TL SHORT TERM...BW LONG TERM....BW