859 FXUS65 KPIH 130418 AFDPIHArea Forecast Discussion National Weather Service Pocatello ID 1018 PM MDT Sun Oct 12 2025
.KEY MESSAGES...
- Showers dissipate this evening with most areas dry through Monday.
- One night of cold temperatures tonight, with Frost Advisory and Freeze Warning for the Snake River Plain.
- Warmer Monday with showers returning for Monday night/Tuesday.
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.SHORT TERM /THROUGH MONDAY NIGHT/... Issued at 110 PM MDT Sun Oct 12 2025
Upper level trough remains across the PacNW and East Idaho today per satellite imagery. Area webcams and surface observations indicate a few showers remain across the region, with observed snow levels between 6000 and 7000 ft. Gusty southwest winds through the Snake Plain expected to continue into the evening, becoming a locally gusty down-valley northerly wind overnight. While showers continue to weaken and dissipate most areas for tonight, temperatures drop in the cold air behind the frontal system. Have issued a Frost Advisory for the Eastern Magic Valley/Shoshone region, and a Freeze Warning for the Upper and Lower Snake Plain and Arco/Mud Lake Desert regions for tonight. Upper trough re-amplifies along the coast Monday, with upper flow once again turning southerly during the day Monday. Drier flow in place for most of the day, but showers may return for the evening and overnight as the deep southerly flow taps some of the tropical remnants currently impacting the Desert Southwest. Temperatures for Monday night should warm several degrees above freezing under the influence of the increased southerly flow and moisture, and do not anticipate additional Frost or Freeze headlines at this time.
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.LONG TERM /TUESDAY THROUGH SUNDAY/... Issued at 110 PM MDT Sun Oct 12 2025
Rain, snow and thunderstorms return starting Tuesday and last through the end of the workweek. We remain in strong southerly flow ahead of the low on Tuesday. We will likely low to mid 60s in warmer spots, especially where we can get downslope winds to aid with any warming and counter increasing clouds/precipitation. the best days for precipitation will be Wednesday and thursday, although Tuesday afternoon and evening are starting to look pretty wet across our area. As we`ve done the past couple of days, let`s dig into some of the "what if forecasts" vs the official Blend of Models forecast. Highs both of those days with our official forecast will be in the mid 40s to low 50s down low. The lower end of the Blend forecasts has highs never getting out of the 40s. In terms of lows both days, the official forecasts is dropping down into the 30s with many spots close enough to 32 for a least a mix of rain and snow for lowest valley spots. The colder end of the Blend of Models would definitely have snow falling (maybe not accumulating) at all elevations in eastern Idaho. If we can get the colder scenario that is still depicted in the ensembles (which help feed the Blend "what if forecasts"), it could be the first snowflakes of the season for some of our more populated cities. Precipitation amounts this early on show 0.30-0.80" over 72 hours for lower elevations, with a 10-40% chance of exceeding that (location dependent). For the mountains, the official forecast right now puts us at 1.0-1.5" for most ranges, with around 2" for the Big Holes and Tetons. There is a less than 10% chance we exceed 2" there at the moment. We should get another break on Saturday, with the chance of precipitation back sometime early next week.
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.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 1002 PM MDT Sun Oct 12 2025
All TAF sites are VFR currently with light winds. Winds will remain light overnight into tomorrow. CIGS should mostly clear out tonight for all TAF sites. There is still a very small chance (less than 10%) for MVFR/IFR CIGS for KIDA, KPIH, and KSUN, so left FEW010 in the TAF for those three sites. Otherwise, expect upper-level clouds moving into the area by tomorrow, Monday, morning becoming a mid-level cloud deck by tomorrow, Monday, afternoon. Vicinity showers should start early Monday evening for KSUN and KBYI. Expect vicinity showers for all TAF sites by Tuesday afternoon becoming widespread showers with MVFR/IFR CIGS by Tuesday evening into Wednesday morning. An upper level low will move into the area from our south Tuesday evening into Wednesday morning.
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.PIH WATCHES/WARNINGS/ADVISORIES... Frost Advisory until 10 AM MDT Monday for IDZ051-055. Freeze Warning until 10 AM MDT Monday for IDZ052>054.
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SHORT TERM...DMH LONG TERM...Keyes AVIATION...TW
NWS PIH Office Area Forecast Discussion