textproduct: Boise

KEY MESSAGES

- Isolated afternoon thunderstorms over southwest Idaho today with gusty outflow winds.

- Slightly below normal temperatures with valley rain showers and mountain snow showers today through tomorrow morning.

- Much cooler temperatures with periods of precipitation Wednesday through Friday.

SHORT TERM /Through Tuesday Night/

Widespread precipitation is filling in south of the Snake River Valley as of 3AM MDT. This is the first push of precipitation along the outer band of the coastal low currently moving inland over northern California. This will push northward throughout the morning, bringing widespread rain below about 7000 feet MSL. Much cooler air will move in behind this initial push of precipitation later today. Temperatures will drop about 5-10 degrees with this cooler air, with snow levels dropping to 5500-6500 feet MSL by mid-morning.

Weak instability exists mainly over high terrain in central Idaho down to the Magic Valley and near the ID-NV border. This will support a slight chance of thunderstorms late this morning through the early evening. Some storms could be strong with gusty outflow winds up to 50 mph thanks to elevated winds aloft with the incoming low. However, the best conditions for any of these stronger thunderstorms is over Eastern Idaho.

As the low moves east of southern Idaho late Sunday, wraparound moisture and cooler northerly flow aloft will push a secondary band of precipitation into the region early Monday. This will bring much lower snow levels (4500-5500 feet MSL) and widespread precipitation to the region through Monday morning. Mountain valleys could see 1-3 inches of snow, mountain passes on US95 and ID21 could see up to 6 inches of snow, and high peaks over 8000 feet could see up to 12 inches of snow by Monday morning. Liquid totals from Sunday and Monday's periods of precipitation will reach 0.50-1.0 inches of rain north of the Treasure Valley, with locally higher amounts over high terrain. Areas near the Nevada border will reach 0.10-0.25 inches of rain. Precipitation will taper off Monday evening as a brief dry period moves in on Tuesday.

LONG TERM /Wednesday through Sunday/

Precipitation will return Wednesday, after Tuesday's brief lull. As a low digs down the coast of British Columbia, widespread precipitation will set in across the area along a cold front. Precipitation will linger through Thursday as the main low moves over our area. Temperatures on Wednesday will be around 10 degrees below normal, cooling to 10-15 degrees below normal Thursday following the cold front. Rain won't be the only precip type in play with this system. The 500mb heights are in the 5-15th percentile of climatology will support lowering snow levels, from 4.5-6.5 kft Wednesday afternoon to valleys floors come Thursday. Breezy winds will also accompany this system Wednesday/Thursday. Over the course of Wednesday through Thursday, liquid precipitation totals of 0.15-0.50 inches are expected throughout E-Oregon and within the Snake Plain, with 0.6-1.5 inches over the Boise/West Central Mountain zones and higher peaks elsewhere. Regarding snowfall, mountains will receive 8-14 inches by Thursday morning (1-4 inches in higher elevation mountain valleys), locations down to 4500 ft MSL will generally see under an inch of snow by Thursday morning. Through Thursday afternoon, locations down to 4500 ft can see additional amounts up to an inch, with 1-3 inches of additional snowfall over the West Central Mountains. Treasure Valley sites could also see snow flurries Thursday, although little to no accumulation is expected.

A warming and drying trend will set in beyond Thursday, as the system moves east and ridging builds in across the area. Temperatures will return to near normal come Saturday, warming even more Sunday. The dry conditions don't appear to last too long, as another system will impact the area come early next week.

AVIATION /06Z Sunday through Monday/

Issued 1158 PM MDT SAT APR 11 2026

Numerous showers continuing through Sunday night. Low VFR-IFR in rain, and IFR-LIFR in mtn snow. Mountains becoming obscured. Snow levels lowering to 5500-6500 ft MSL by late morning. Isolated thunderstorms in the afternoon mainly in SW Idaho, capable of gusts to 25-40 kt and graupel/small hail. Surface winds: variable 5-15 kt, then S-W 10-20 kt with gusts to 20-35 kt in the afternoon. Winds aloft at 10kft MSL: SW 10-25 kt.

KBOI...Generally VFR. Rain showers returning Sun/09Z-10Z, continuing through Sunday night. Rain will be moderate/heavy at times, creating MVFR conditions. A slight chance of thunderstorms (20%) during the early afternoon, capable of gusts to 25-40 kt and graupel/small hail. Surface winds outside of showers: E-S 5-15 kt.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.