textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- About ten degrees hotter Sunday, with lower elevations reaching 90 degrees for the first time this year.

- Record high temps on Tuesday with temperatures in the mid to upper 90s in the lower valleys.

- Cooler Wednesday with a chance of showers and thunderstorms.

SHORT TERM /Through Tuesday Night/

Issued 232 AM MDT SUN MAY 10 2026 Strong high pressure building over the northwest region will bring unseasonably warm temperatures across the area on Sunday, with valleys expected to reach the lower 90s for the first time this year. A weak shortwave trough passing north of our area will bring strong wind gusts up to 35 mph over east-central OR near Baker County and northern Malheur County late Sunday night into early morning Monday. A slight cooldown is expected Monday, with peak temperatures expected to hover in the mid 80s. A powerful ridge of high pressure will quickly build into the entire western CONUS on Tuesday, bringing exceptionally warm temperatures over our area. Most valley areas are expecting to see peak temperatures in the mid to upper 90s, likely breaking daily records. The ridge may steer some upper moisture over the Great Basin late Tuesday, potentially favoring some high clouds and scattered dry thunderstorms over the ID/NV border area.

LONG TERM /Wednesday through Sunday/

Issued 232 AM MDT SUN MAY 10 2026 A trough will approach the region on Wednesday with southerly flow over the area. Subtropical moisture will move northward from Baja on Wednesday, with precipitable water values reaching the 90th percentile. This combined with the trough moving inland will trigger scattered showers and thunderstorms on Wednesday afternoon and evening. Forecast precipitation should be higher than what is in there. Shear values are sufficient too for a severe weather threat with a few organized strong storms possible. The trough moves inland over southeast OR and southwest ID on Thursday with good model agreement. The current WPC/NBM forecast does not reflect this trough, so temperatures are around 10 to 15 degrees too warm for this event and probability of precipitation should be rain likely for most of the area on Thursday. Cooler temperatures continue into Sunday behind the trough with zonal flow over the area. Current forecast is too warm Friday through Sunday.

AVIATION /12Z Sunday through Monday/

Issued 624 AM MDT SUN MAY 10 2026 VFR. Surface winds: SW-SE 10kt this morning increasing to 10-20kt this afternoon, becoming NW 10-20kt this evening with gusts up to 30kt near KONO KBKE after sunset. Winds aloft at 10kft MSL: SW 15-25kt.

KBOI...VFR. SE winds 10-20kt becoming NW 10kt after sunset.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.