412 FXUS65 KPIH 011117 AFDPIH Area Forecast Discussion National Weather Service Pocatello ID 517 AM MDT Sun Jun 1 2025 .KEY MESSAGES... - Isolated light showers and dry thunderstorms for Sunday afternoon/Sunday night. Breezy in the Snake River plain. - Cooling trend to afternoon highs starts Sunday, continues through Tuesday. - Slight chance to chance of light showers Monday in eastern mountains, showers and thunderstorms on Tuesday afternoon. && .SHORT TERM /THROUGH MONDAY NIGHT/... Issued at 149 AM MDT Sun Jun 1 2025 Upper level trof moves east through Idaho today and tonight and expect showers and thunderstorms mainly along the Montana border today with a marginal risk of severe again also near the Montana border in the Upper Snake River Highlands. There is at least a chance or slight chance everywhere else. Do not expect significant precipitation but main threat will be gusty winds near storms and also hail potential. Winds will pick up in the Snake River Plain with some 15 to 25 mph sustained winds. Will hold off locally on Lake Wind Advisory as strongest winds should be further north. Showers will continue overnight in the eastern mountains for the most part. It will remain very warm today with highs 70 mountains and 80s valleys. It will begin to cool off substantially tonight with lows back into the 30s and 40 mountains and 40s to lower 50s valleys. Highs Monday much cooler in the 60s and 70s. It will be mainly dry with morning showers in the Upper snake Highlands again but dry elsewhere and mainly dry Monday afternoon and night. Lows Monday night will be in the 30s mountains and 40s valleys. 10 to 15 mph winds will be present Monday and not expected to be as breezy as today. && .LONG TERM /TUESDAY THROUGH SATURDAY/... Issued at 149 AM MDT Sun Jun 1 2025 Persistent longwave troughing remains forecast throughout next week, with a few individual disturbances/shortwave troughs cutting through the region at times. These features continue to look very low-impact for southeast Idaho with day-to-day PoPs generally confined to the eastern highlands and Island Park areas. Tuesday and Tuesday night continue to look like the best shot at better coverage of a few showers and thunderstorms, although the eastern Magic Valley and Raft River regions may yet stay completely dry. Daily winds have trended lighter in the forecast with the breeziest conditions holding off until Friday and Saturday as the pressure gradient tightens in response to a more organized low pressure system to our northeast dropping out of Canada. Temperatures will modestly trend warmer over the course of the week...starting in the 60s to low 70s Tuesday and eventually reaching the upper 70s to mid 80s by Saturday. && .AVIATION /12Z TAFS THROUGH 12Z MONDAY/... Issued at 517 AM MDT Sun Jun 1 2025 A trough of low pressure will induce increasing WSW winds this morning (then continuing right into the overnight tonight), followed by a chance of showers and thunderstorms this afternoon and evening. The most favored corridors for thunderstorm development remain from the eastern Central Mountains northeast along the Montana border (north of KIDA and KDIJ), and also across the Raft River region and Utah border (south of KBYI and KPIH), but our concern is that storms may either be in close enough proximity to all of these terminals... or additional cells not well modeled by high-res guidance may fire along storm-induced outflow boundaries...to bring some impacts starting around 23z/5pm at KBYI and 01z/7pm at KPIH/KIDA/KDIJ (late show by local standards), so have gone ahead and defined VCTS periods in the 12z TAF package. Overall forecast confidence in occurrence and timing of nearby storms is moderate at best...some "nowcasting" may be required as we monitor real-time trends this afternoon. The primary hazard with storms today will be gusty/erratic downdraft and outflow winds potentially reaching 50-60 MPH in a cell or two (as hinted at in the HREF wind gust ensemble max), while other hazards such as hail will be more significant north of KIDA and KDIJ where better deep-layer shear resides. KSUN should be just far enough west to stay away from thunderstorm issues, but all guidance strongly supports a wind shift from the normal SE diurnal flow to a SW (gusty) runway crosswind this afternoon...a few models go as early as 20z/2pm but have nudged this to 21z based on climatology. Clouds look to remain strongly VFR...may see some areas of BKN develop late this afternoon into the first half of the night if storm coverage is decent and spreading cumulonimbus anvils are prominent. && .FIRE WEATHER... Issued at 149 AM MDT Sun May 31 2025 An upper level trof approaching will bring a chance for showers and thunderstorms with the potential for strong storms mainly in zones 475, 476 and 411 and northern parts of 410. Winds will increase with 15 to 25 mph winds in parts of zone 410 as well this afternoon and parts of 425 and 475 and 476. Minimum humidity will be increased today with slightly cooler temperatures and most locations above 20 percent. Cooler temperatures will move in Monday with about a 10 degree drop from today but humidity will decrease with substantially drier air moving in. Most convective activity limited to zone 411. Showers likely a bit more widespread on Tuesday with another upper trof sliding south. && .PIH WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...GK LONG TERM...KSmith AVIATION...KSmith FIRE WEATHER...GK