Area Forecast Discussion
Issued by NWS Pocatello, ID
Issued by NWS Pocatello, ID
312 FXUS65 KPIH 310838 AFDPIH Area Forecast Discussion National Weather Service Pocatello ID 238 AM MDT Fri May 31 2024 .SHORT TERM...Today and Saturday Quiet weather expected to round out the work week as weak upper level ridging builds over the region today. This will allow for mostly clear skies throughout the day, light winds and no precipitation. The morning will start out chilly, especially outside of the urban areas where a Frost Advisory continues until 8AM. Temperatures along the interstate corridors are still generally in the 40s but outside of those areas upper 30s have been observed. Under high pressure, temps will rise quickly this morning and nearing seasonal norms for daytime highs which means upper 60s and lower 70s in the valley locations, 60s in the mountains. Not expecting any frost concerns overnight Friday into Saturday as overnight lows will generally be in the low to mid 40s. Warming trend continues into the day Saturday with upper 70s and lower 80s looking likely throughout the Snake Plain and Magic Valley. A weak shortwave moving well north of the region will likely bring increasing clouds throughout the day. Could get a few showers and thunderstorms to develop as well later in the afternoon and into the evening. Hi-res CAMs are much more aggressive with this compared to the NBM which is nearly dry regionwide. For now, the forecast at least shows low-end PoPs along the Montana Divide and into the eastern highlands but could see a greater expansion on subsequent forecasts based on model trends. McKaughan .LONG TERM...Sunday through next Friday. While we will be in nearly zonal flow on Sunday, a weak shortwave will pass through our area and keep a 20 to 40 percent chance of showers and storms around the upper Snake Plain and northern half of the Eastern Highlands. Sunday will be warm with highs in the 60s and 70s with wind gusts 25 to 35 mph through much of eastern Idaho. Some discrepancies remain for the track of the low across southern Canada on Monday with the ECMWF wanting to dig it farther south into north- central Montana while the GFS keeps it in Canada. While the models do have their differences, both want to bring in showers and storms for the day. The best chance for those will be in the Central Mountains and Eastern Highlands, but even the Snake Plain, Magic Valley, and Southern Hills will have at least a 30 to 50 percent chance of precipitation on Monday. The bulk of the moisture will fall in central Idaho with a 30 to 50 percent chance of QPF of a half an inch up in the Stanley area and a 10 to 30 percent chance of the same in the Island Park area throughout Monday into early Tuesday. This is the "Marginal" risk area the WPC has highlighted in their Day 4 Excessive Rainfall Outlook. Elsewhere, the 75th percentile QPF totals generally range from a tenth to two tenths of an inch. This system will also keep the breezy winds around, especially in the upper Snake Plain/Mud Lake/Arco Desert areas where there is already a 40 to 60 percent chance of gusts reaching 45 mph. A few showers will linger into Tuesday morning and the wind will continue to gust 25 to 35 mph. After Tuesday, high pressure moves in and the heat really kicks up. Highs on Wednesday will be in the 70s and 80s and for Thursday and Friday many of us will make a run at hitting our first 90s of 2024. There is a 40 to 60 percent chance that the lower Snake Plain and eastern Magic Valley will hit 90 by Friday afternoon. AMM && .AVIATION... No major aviation concerns today with weak high pressure building over the region. Winds will be light and skies mostly clear throughout the period. VFR to prevail. McKaughan && .FIRE WEATHER... Northwest flow aloft continues today and our weather remains warm and dry. Highs will again be in the 60s, though parts of the Snake Plain and Magic Valley will return to the low to mid 70s. Winds will be light for most with gusts around 20 to 25 mph in the Arco Desert/Mud Lake area. Expect min RHs to be in the teens and 20s throughout eastern Idaho today and tomorrow. We warm up for Saturday, too, with highs almost 10 degrees warmer than today in the Magic Valley and Snake Plain. A weak shortwave passing through this weekend brings a 20 to 40 percent chance for some dry thunderstorms up along the Idaho/Montana state line and in the Eastern Highlands. A more organized system looks to bring a more widespread mix of wet and dry storms to eastern Idaho on Monday before we dry out and really heat up in the second half of next week. AMM && .PIH WATCHES/WARNINGS/ADVISORIES... Frost Advisory until 8 AM MDT this morning for IDZ051>054. && $$