Area Forecast Discussion

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Continued dry and warming through early Tuesday, but beginning to cool in eastern Oregon later Tuesday. - Showers and thunderstorms, windy, and much cooler Wednesday as a cold front moves through.

SHORT TERM /Through Tuesday Night/

Issued 312 AM MDT SUN APR 19 2026 Continued dry and warming today and Monday as an upper ridge holds over the interior northwest, while a Pacific upper low near 45/139 moves slowly south. High temps today will be about 10 degrees warmer than yesterday, with another 5 degrees warming Monday. Tuesday will continue warm in Idaho but begin to cool in Oregon as the upper ridge begins to shift eastward and the Pacific low moves toward the northern California coast. The approaching low will begin showers and thunderstorms in Harney and Baker Counties Tuesday, with showers spreading eastward across the rest of our CWA Tuesday night. Winds will be breezy south or southeast through the short term.|

LONG TERM /Wednesday through Sunday/

Issued 312 AM MDT SUN APR 19 2026 A prominent Pacific low will move overhead on Wednesday and trigger a sharp cool-down across SE Oregon and SW Idaho...with max temperatures lowering as much as 20-30 degrees from Tuesday. Numerous showers will dominate the area Wednesday into early Thursday, with snow levels ranging 5000-6500 ft MSL. As a result, several inches of snow accumulation will develop across the higher terrain once ground temps cool, while moderate rainfall totals can be anticipated for low/mid elevations. Windy conditions will continue through Wednesday, with highest gusts located south and west of the W Snake Plain. Winds will gradually subside for Thursday, but remain breezy throughout the afternoon. As the center of the low departs toward the east, cool northerly flow will keep temperatures near to slightly below normal through the rest of the week. Thereafter, near- normal temps and unsettled conditions are forecast into the weekend as troughing persists across the Northwest U.S.

AVIATION /12Z Sunday through Monday/

Issued 521 AM MDT SUN APR 19 2026

VFR. Surface winds: variable 5-15 kt. Then, E-S 5-15 kt with gusts to 15-25 kt in the afternoon. Winds aloft at 10kft MSL: S-SW 10-20 kt.

KBOI...VFR. Surface winds: SE 5-12 kt, except brief period of light and variable late morning. Occasional afternoon/eve E-SE gusts around 20 kt.

BOI WATCHES / WARNINGS / ADVISORIES

ID...None.

OR...None.