FXUS65 KPIH 201025 AFDPIH Area Forecast Discussion National Weather Service Pocatello ID 425 AM MDT Wed May 20 2026 .KEY MESSAGES... - Frost & freeze conditions persist through the rest of the week - Increasing chance of showers and thunderstorms Wednesday afternoon and Thursday - Temperatures return to 10-15 degrees ABOVE AVERAGE over the weekend && .DISCUSSION... Issued at 1209 AM MDT Wed May 20 2026 Trends still point toward an increasing chance of showers and thunderstorms later today and continuing through Thursday afternoon. Low pressure drops south out of Canada and actually deepens as it swings across the state. At the moment, we may see little to no chance of precipitation once we get into the Stanley Basin and Wood River Valley. Precipitation amounts range from just a few hundredths to closer to 0.25" across portions of the eastern and southeast highlands. In reality, wherever we can get heavier showers or bands to develop, 0.25" can easily be achieved through tomorrow. Looking at probability forecasts, the higher end amounts in any given 12 hour period do indicate that 0.30-0.50" could occur in these situations. It will be breezy occasionally in the next 36 hours, with the only impact coming Thursday with gusty northeast winds on American Falls Reservoir. We will likely exceed thresholds for a northeast wind event and a LAKE WIND ADVISORY needed down the road. It will be just cold enough that we will will see some light snow accumulations on highest peaks and ridgelines as well. It looks like frost/freeze conditions (outside of typical colder spots this time of year) may linger through Saturday morning. We have a FREEZE WARNING and FROST ADVISORY for the Snake Plain and Magic Valley for this morning. For tonight, a FROST ADVISORY may be needed for portions the Arco Desert and INL area. Friday morning will likely see freeze conditions across most of the Snake Plain, and frost conditions in rural spots Saturday morning. We do eventually warm back up, but it won't be until we return to southwest flow over the weekend and early next week. We will be well into the 70s and 80s for afternoon highs. With the next low moving into the region starting Tuesday, we will quickly drop back into the 60s (based on the latest Blend of Models forecasts) by midweek. We will likely also not be shower or storm free ahead of that storm. We continue to see small surges of moistures which COULD set of a few light showers/sprinkles and thunderstorms. Right now, we are keeping any potential at 15% or less until Tuesday. && .AVIATION /12Z TAFS THROUGH 12Z THURSDAY/... Issued at 418 AM MDT Wed May 20 2026 We will see showers and isolated thunderstorms spreading across central and eastern Idaho through the next 24 hours. We are expecting to remain VFR through the period, although if we get heavier precipitation to fall at a particular airport, we could quickly drop to VFR conditions. The pattern suggests that PIH, IDA, and DIJ will be most impacted. BYI and especially SUN will be on the edge of any more widespread area of precipitation, but certainly some showers are not out of the question at those TAF sites. We are maintaining VCSH at DIJ, IDA, and PIH for the latest update. It is expected to see that converted to -SHRA with some mention of thunderstorms later today and certainly through the period, as isolated storms are possible after sunset. && .PIH WATCHES/WARNINGS/ADVISORIES... Frost Advisory until 9 AM MDT this morning for IDZ051-053>055. Freeze Warning until 9 AM MDT this morning for IDZ052. && $$ DISCUSSION...Keyes AVIATION...Keyes