


Area Forecast Discussion
Issued by NWS Pocatello, ID
Issued by NWS Pocatello, ID
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931 FXUS65 KPIH 231132 AFDPIH Area Forecast Discussion National Weather Service Pocatello ID 532 AM MDT Fri May 23 2025 .KEY MESSAGES... - Slight chance of showers and thunderstorms in the mountains and highlands for Friday afternoon and evening. - Slight chance of showers and thunderstorms Saturday afternoon for the eastern and southeastern highlands. - Dry and warming through Memorial Day in the Snake River plain and eastern Magic Valley. && .SHORT TERM /THROUGH SATURDAY NIGHT/... Issued at 250 AM MDT Fri May 23 2025 Today will not be quite an exact repeat of Thursday, but close to it! Think of it as Thursday-lite. Winds will be lighter over all and any shower or thunderstorm activity will be even more confined to the Central Mountains and Eastern Highlands/Island Park areas. We`ll see these as a weak shortwave passes through later this evening/early Saturday. Look for gusts with any storm to be around 40 mph, though a rogue gust closer to 50 isn`t totally out of the question. Winds will pick up a bit tonight with gusts around 25 to 30 mph as the shortwave passes through Eastern Idaho. Highs this afternoon return to the low to mid 70s throughout the eastern Magic Valley and Snake River Plain with mid to upper 60s in the mid elevations. Our warming trend will continue into the holiday weekend with highs on Saturday being about 3 to 5 degrees cooler. Saturday will be a mostly dry day for many, but we keep around a 20 percent chance of a few showers or storms in the Eastern and Southeastern Highlands. && .LONG TERM /SUNDAY THROUGH THURSDAY/... Issued at 250 AM MDT Fri May 23 2025 High pressure will continue to prevail across eastern Idaho to finish out Memorial Day Weekend with highs in the 70s/80s as conditions remain predominantly dry with plenty of sunshine. As a 500 mb trough to the south works east over the Continental Divide on Sunday, a ridge of high pressure will continue to build in from the west, bringing warmer temperatures and dry conditions outside of some isolated showers and thunderstorms in the higher terrain, primarily east of Interstate 15. For Memorial Day, dry conditions will continue through much of the day as our next 500 mb trough begins to build into the Gem State with isolated showers and storms possible during the afternoon and evening hours, mostly in the higher terrain. This system will help knock down temperatures by a few degrees for Tuesday courtesy of increased cloud cover and as it continues its progression east, support another round of diurnal showers and storms. That aforementioned ridge of high pressure looks to regain some ground for Wednesday and Thursday, leading to temperatures trending a bit warmer with highs about 10-15 degrees above normal for late May in the 70s to mid 80s as daily, diurnal showers and thunderstorms remain possible during the afternoon and evening both days. Deterministic model guidance diverges mid to late next week as the GFS supports a more active and wetter pattern with several systems moving overhead while in contrast, the ECMWF keeps a ridge of high pressure solidly overhead. The NBM continues to be in the middle of the road of these two, keeping with the warm temperatures but only supporting isolated shower and storm potential each day. The NBM also reflects more closely to GFS/ECMWF ensemble guidance which keeps with an extended stretch of above normal temperatures and mostly dry conditions outside of some isolated showers and storms each afternoon and evening. This looks like the pattern we will keep around to finish out May into early June with above normal temperatures and near normal to below normal precipitation expected in the latest CPC 6 to 10 and 8 to 14 Day Outlooks. && .AVIATION /12Z TAFS THROUGH 12Z SATURDAY/... Issued at 530 AM MDT Fri May 23 2025 Predominant VFR and dry conditions with light winds will continue across eastern Idaho today with another round of isolated showers and thunderstorms possible further north this afternoon and evening. Best chances will exist in the Central Mountains and Montana border/Island Park region with a 10-20% chance at KSUN and less than a 10% chance elsewhere at other terminals. With latest model guidance keeping the bulk of activity north of KSUN, so we will keep with a dry forecast for now as we continue to evaluate the potential. Clear skies will start off the day ahead of increasing mid/upper-level clouds building in by midday which will persist overnight tonight. && .FIRE WEATHER... Issued at 250 AM MDT Fri May 23 2025 Like yesterday, we`ll keep around some showers and thunderstorms throughout Fire Weather Zones 411, 475, and 476 as a weak shortwave passes through Eastern Idaho late today/early Saturday. Any wind gusts with storms today would be closer to 40 mph and gusts outside of storms will pick up to around 25 to 30 mph at times. Parts of Zone 413 will see about a 20 percent chance of a shower or storm as we get into Saturday. Temperatures continue their warming trend through the holiday weekend with dry conditions through the eastern Magic Valley and Snake River Plain. && .PIH WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...AMM LONG TERM...MacKay AVIATION...MacKay FIRE WEATHER...AMM