Area Forecast Discussion
Issued by NWS Pocatello, ID
Issued by NWS Pocatello, ID
277 FXUS65 KPIH 271921 AFDPIH Area Forecast Discussion National Weather Service Pocatello ID 121 PM MDT Sat Apr 27 2024 .SHORT TERM...Tonight and Sunday As expected, it`s been a rather dreary late April day across eastern Idaho. Afternoon satellite imagery shows continued widespread cloud cover across the area associated with an upper low to our south. Still seeing lots of widespread light to moderate rain showers (snow above 7500 ft or so) this afternoon and these will gradually begin to taper off throughout the rest of the day. Before it`s over however, could see just enough instability to support some isolated thunderstorms across the eastern highlands later today. Temps are definitely on the cool side of normal with all the clouds and rain around. 40s and lower 50s are the norm for most of us but the Magic Valley has been a touch warmer with less cloud cover and rain. This is where the winds have been a bit breezy. For Sunday, the low across the Four Corners continues to move away from our region and into the Central Plains. This will allow our upper flow to become more zonal clearing things out a bit. Models do show some lingering moisture mainly across the eastern highlands tomorrow setting up what appears to be a high PoP/low QPF kinda day from them with lingering clouds and rain showers. Elsewhere we should see a bit more clearing and warmer temps with some low 60s potentially into the lower valleys. Higher terrain will remain in 40s and 50s. McKaughan .LONG TERM...Monday through Saturday The weather looks really now unsettled throughout the week. Multiple areas of low pressure will impact central and eastern Idaho, especially through midweek. Highs look to stay in the 50s in the valleys midweek, with 30s and 40s in the mountains daily. Each storm doesn`t necessarily to bring a ton of rain and mountain snow our way, but each little push adds to our snowpack and also to our rivers and creeks. One of the bigger impacts looks to be Monday, but not in terms of precipitation. Trends continue to show a solid WIND ADVISORY event across portions of the Snake Plain and Magic Valley, potentially extending south into the South Hills and Albion Mountains. Probability forecasts show winds solidly above 45 mph, especially across the Snake Plain and Magic Valley. There is a 60+% chance of exceeding 55mph in a narrow corridor across the Lava Beds and INL, as well as around Yale. Elsewhere across the Plain, those percentages rapidly drop to under 35% in isolated spots. It will still be breezy on Tuesday, but quite a bit less vs Monday. There is only a 40-70% chance of gusts over 45 mph across portions of the Upper Snake Plain and the Lava Beds. Keyes && .AVIATION... Showers with a few thunderstorms remain possible through this evening. Where rain has been more steady so far, we`ve see down to IFR conditions at times. With things becoming more showery, expect more breaks in the clouds and overall weather being VFR. IF we can get a shower or storm over one of the TAF sites, we do anticipate drops to IFR for brief periods of time. Winds will gust at time to 25kts at BYI, PIH and IDA today, and 20-30kts Sunday. At SUN, 10-20kt winds are expected until sunset. Of note, it does appear that we should see the switch to a northwest wind sooner than usual, today, between 22-00z (4-6pm MDT). Keyes && .HYDROLOGY... Water levels remain elevated on the Portneuf River from Pocatello to Chesterfield Reservoir where River Flood Warnings remain in effect until further notice. Minor to moderate flooding is ongoing in this area with both the Pocatello and Topaz river gauges forecast to crest this weekend before dropping slightly heading into early next week. Further north and west along the Snake River, water managers have increased releases from upstream reservoirs leading to high flows in excess of 10,000 cfs downstream from Palisades to Milner. The Snake River near Heise and Snake River at Lorenzo gauges have reached action stage as a result and are expected to be at that stage until further notice. Willow Creek below Tex Creek above Ririe Reservoir and the Blackfoot River above Blackfoot Reservoir both also continue to be in action stage since Monday with no major impacts seen elsewhere in our CWA as of Saturday afternoon. MacKay && .PIH WATCHES/WARNINGS/ADVISORIES... None. && $$