548 FXUS65 KPIH 050033 AFDPIH Area Forecast Discussion National Weather Service Pocatello ID 633 PM MDT Tue Jun 4 2019 .UPDATE... Minor update to account for lingering thunderstorms over extreme southeast Idaho. Should fizzle out within the next couple of hours. Valle && .PREV DISCUSSION... /issued 216 PM MDT Tue Jun 4 2019/ SHORT TERM...Tonight through Fri afternoon. Showers and thunderstorms are still a threat tonight, but mostly pulse-type of cells and limited to the area between Interstate 15 and the Wyoming border. There is an upper level wind shift occurring that will strengthen overnight and for Wed expect dry conditions over the entire forecast area with temperatures warming into the 80s in the Snake River plain/eastern Magic Valley. The arrival of westerlies will put the forecast area in the storm track however. And a strong, almost winter-like storm is expected to arrive in the western zones on Thu morning and spread its effects eastward. The storm will intensify for Fri, and by Fri night will bring temperatures to the point where accumulating snow is probable at elevations in the central Idaho mountains and along the Montana border region, currently in the range of 1 to 2 inches. Thu night and Fri are also expected to be windy to very windy. Temperatures start the plummet down by 15 to 20 deg F between Thu and Fri, with widespread temperatures 8 to 12 deg F below normal for the time of year. Main concern will be the intensity of thunderstorms with the associated front-the bigger the temperature difference, the more potential for severe thunderstorms, and this can be seen in that the Storm Prediction Center has put nearly all of southern Idaho in a marginal threat of severe thunderstorms/tornado activity. Messick LONG TERM...Friday night through next Tuesday. Saturday will be cold and wet across eastern Idaho. Snow levels will likely down to valley floors or very close to it in the central mountains ranging to 6000- 6500ft near the Wyoming border in the morning. They do jump a bit to 6500-7000ft everywhere in the afternoon. Most of the precipitation falls in the central mountains, Island Park/Centennial Mountains and into Driggs/Big Hole Mountains. The chance of showers decreases quickly south and west from those areas. The afternoon breeze will just add to that cold, damp feeling with 15-30mph in many locales. The low will begin moving out Sunday, with just lingering isolated/scattered showers across the central mountains, along the Montana Divide, and south to around Soda Springs. We might see a rogue shower drift across the Upper Snake Plain and Arco Desert. Temperatures don't jump up much, on average only around 5 degrees. Beyond that, things looks MUCH drier and warmer. High pressure will try and build in, but given recent struggles with the extended pattern in the models...that forecast is based on caution. We might see a couple of storms clip the Divide for isolated showers early next week, but right now that chance is very low. Keyes AVIATION...The only potential for showers or storms is really in the eastern highlands. We could still see something develop to the west of Idaho Falls and drift across the Snake Plain. We have at minimum VCTS for DIJ and IDA into this evening. Gusty winds over 25kts and a brief downpour are possible. The threat of small hail is lower than previous days, but not zero. Otherwise, other sites will be VFR and expect VFR conditions for ALL TAF sites Wednesday. Keyes HYDROLOGY...Wood River at Hailey stretch of river is still in minor flood stage. After no reports of flooding impact on the Raft River, decided to cancel the Raft River flood warning, but it is running high and will need to be monitored. Big Lost and Henrys Fork are also starting to reach action stage and will get very close to their minor flood stages in the next three days. Antelope Creek in the central Idaho mountains and Valley Creek in Stanley will also need to be monitored during the next week. && .PIH WATCHES/WARNINGS/ADVISORIES... None. && $$