Area Forecast Discussion

KEY MESSAGES

- Another freeze this morning. Not nearly as cold tonight into Monday but a few spots will approach the freezing mark.

- Significant Warming Trend: A major warm-up begins today with high pressure amplifying, returning temperatures to the 70s in lower valleys for the next few days

- Mid-Week Active Pattern: A broad Pacific system is progged to move inland late Tuesday into Wednesday, bringing cooler temperatures and increased precipitation chances to Eastern Idaho.

DISCUSSION

Issued at 1247 AM MDT Sun Apr 19 2026

A widespread freeze remains ongoing across the region this morning, with high pressure forecast to amplify significantly over the region today. While some mid to high level clouds may filter through during the afternoon, dry conditions will prevail today. Tonight temperatures will remain cool but not nearly as cold as the past few nights. Considered a Frost Advisory for the Arco Desert and Snake Plain zones but the duration of the coldest temps is so brief and compared to the last few nights, impacts would be minimal compared to previous nights. Nevertheless, a few hours of temps at or just above freezing will be possible early Monday morning in rural areas within the aforementioned zones.

High pressure will remain in control as we transition into the work week. Temperatures are expected to climb well above seasonal norms today, with highs returning to the 70s for lower valley locations. These temps warm even further Monday and Tuesday with mid to upper 70s looking likely in the Snake Plain and Magic Valley. These readings will be some 10 to 15 degrees above seasonal norms.

The next weather system is expected to shift inland by Wednesday as a broad upper-level low moves out of the Pacific and into the Intermountain West. This pattern change will usher in cooler temperatures and higher precipitation chances for the Wednesday through Friday timeframe. The surface pressure gradient is also expected to tighten Tuesday through Thursday, likely resulting in several breezy days across the region. Current ensemble guidance suggests this system will be warmer than the most recent cold snap; consequently, rain is expected to be the dominant precipitation type below 6,500 feet, though light snowfall remains possible for higher elevations. Confidence in the exact timing and progression of this mid-to- late week system remains low as models continue to show spread in the eventual track of the upper trough. For now, temps look to remain at or on the cooler side of normal from mid week into next weekend but this likely ultimately depends on the progression of our mid week system and the upper level pattern which models continue to struggle with.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 1102 AM MDT Sun Apr 19 2026

Another period of VFR conditions on the way with some increase in higher clouds expected.

PIH WATCHES / WARNINGS / ADVISORIES

None.