Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
338 FXUS65 KBOI 012045 AFDBOI Area Forecast Discussion National Weather Service Boise ID 245 PM MDT Wed May 1 2024 .SHORT TERM...Tonight through Friday night...A weak shortwave is continuing to move southeastward across central Idaho, sustaining scattered showers primarily over the West Central and Boise Mountains. Additionally, weak showers have cropped up in Baker County and the Lower Treasure Valley. Snow levels are hovering around 3500 feet, leading to predominantly snowy conditions in mountainous regions, while lower valleys may experience a mix of rain and snow. However, snow accumulation is expected to be minimal, with most areas receiving between 0.1 to 0.3. In the Treasure Valley, showers will likely yield little to no rainfall until early evening. There`s a slight possibility of lightning strikes, particularly in the central Idaho mountains. Shower activity will wane as the evening progresses and the low pressure system shifts over Utah. In the Western Magic Valley, gusts of up to 40 MPH have been observed, anticipated to persist through the evening before tapering off post-sunset. Overnight, there will be a brief respite before another low- pressure system traverses the forecast area on Thursday. The brunt of precipitation is forecasted to remain south and west of the Western Snake River Plain, initially affecting Southeast Oregon and later moving into the Southwest Highlands on Thursday afternoon. This region has a 30% chance of receiving over 0.10 of rainfall. Furthermore, scattered showers and isolated thunderstorms are expected to develop over the central Idaho Mountains Thursday afternoon due to increased instability and dynamics associated with the approaching low center. Friday will bring warm and dry conditions as a weak ridge builds over the area ahead of the next upper-level low. Temperatures are forecasted to rise above normal with heightened southerly flow aloft. .LONG TERM...Saturday through Wednesday...A deep upper low will move into the Pacific Northwest on Saturday. Ahead of the low, southwest flow will bring mild temperatures to much of the area, with lower valley highs in the upper 60s to mid 70s. However, southeast Oregon will be closer to the low center and significantly cooler. Warm temperatures will be aided by gusty southeasterly winds, with gusts up to 40 mph in the Snake Basin. Precipitation will move into southeast Oregon by Saturday morning, then push into southwest Idaho Saturday afternoon and evening. A band of moderate to heavy precipitation may develop along a cold front as the low moves east. Snow levels will be high initially, then fall to 3500-6000 feet as the low center moves overhead. The lowest snow levels will develop where the low center and core of cold air aloft moves across. The coldest air looks to arrive mainly behind the cold front on Sunday, with significant snow accumulations limited to the mountains. However, light snow accumulations are possible above 3500 feet. Sunday will be cool and showery as the low tracks across our area. Highs will be 10-15 degrees below normal, and gusty northwest winds will make it feel even colder. The pattern will remain active into early next week as a large upper level trough develops across the northern US, with shortwave troughs rotating through our area under northwesterly flow aloft. This will bring periodic chances of rain and snow with fluctuating snow levels, but at times dropping as low as 3000-3500 feet. Each day will bring a 20-60% chance of precipitation, with the highest chances Monday and Wednesday. Precipitation amounts with each system look to be light. Temperatures will remain 5-10 degrees below normal. Each passing system will bring periods of gusty winds, particularly in the Magic Valley. && .AVIATION...Mainly VFR. Scattered rain/snow showers and isolated thunderstorms, mainly north of a KBKE-KBOI-KSUN line, will taper off this evening. Snow showers obscuring mountains and producing brief MVFR/IFR conditions. Snow levels 3500-4500 ft MSL. Additional rain and snow will move into SE Oregon overnight, with isolated to scattered rain and snow showers moving into SW Idaho on Thursday. Surface winds: W-NW 5-15 kt, with gusts to 30 kt through Thurs/03z near KTWF/KJER/KGNG, becoming variable less than 10 kt overnight. NW winds 5-15 kt redeveloping by Thursday afternoon. Winds aloft at 10kft MSL: SW-NW 15-25 kt. KBOI...VFR with scattered to broken clouds 4000-9000 ft AGL. Isolated showers will taper off by early evening. Snow levels around 4000 ft. A 20% chance of showers will redevelop on Thursday. Surface winds generally NW 5-15 kt with gusts to around 20 kt through 03Z, becoming SE 5-10 kt overnight, then back to NW by 21Z Thursday. && .CLIMATE...April 2024 brought unusual weather to Boise, featuring significant precipitation and snowfall. From January 1st through April 30th, 2024, Boise amassed a total precipitation of 8.87 inches, marking it as the 6th wettest year on record for that period. A total of 2.37 inches of rain made April the 9th wettest on record. On April 4th, Boise set a new daily rainfall record with 1.09 inches, followed by another record-breaking day on April 5th, with 1.05 inches of rainfall. This occurrence is noteworthy as it`s only the second time in Boise`s history that the city experienced 1 inch or more of rainfall on consecutive days. Additionally, April 5th saw Boise hit a high temperature of 39 degrees Fahrenheit, the coldest April high since 1936. On the same day, 2.1 inches of snowfall shattered the daily snowfall record, marking the first instance of such significant April snowfall since 1969. This also made April 2024 tied for the 12th snowiest on Record. && .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 SHORT TERM...JDS LONG TERM....ST AVIATION.....ST CLIMATE......JDS