Area Forecast Discussion
Issued by NWS Pocatello, ID
Issued by NWS Pocatello, ID
471 FXUS65 KPIH 202003 AFDPIH Area Forecast Discussion National Weather Service Pocatello ID 203 PM MDT Mon May 20 2024 .SHORT TERM...Tonight and Tuesday Afternoon satellite imagery continues to show an upper trough digging across the region this afternoon. Seeing increasing cloud cover and showers across the central mountains and into the Arco Desert and hi-res CAMs show these continuing to push southward over the remainder of the day and into the evening. Precipitation will be showery in nature though so not everyone will get in on the action. Cooler temps and cloud cover will keep snow levels around 6500-7000 ft so any elevations above that level will see some snow showers. Valley temps are only in the 50s this afternoon and another seasonably cool night is expected. A frost advisory is in place once again across the growing region and a few rural spots could certainly drop below freezing but this isn`t expected to be widespread. Tomorrow we`ll continue to feel the influence of the trough with another round of showers and storms possible. PoPs tomorrow generally favor the eastern highlands though as the trough continues to move east of the area with very weak riding across western portions of the forecast area. With less cloud cover, daytime highs should be able to get closer to 60 for the lower terrain while remaining in the 50s across the high country. A more impactful system looks to move into the region for mid-week however. McKaughan .LONG TERM...Wednesday through Memorial Day Our next low will impact central and eastern Idaho midweek. There are some subtle differences which could impact a more southern push of better moisture, but the consensus right now is that the central mountains and eastern highlands will see the most rain or snow at the moment. Early snowfall totals have 6" or less between 6000-9000ft, with locally higher numbers on the highest peaks and ridges. Probability forecasts also support amounts above 6" (55-85%) for places like Borah, and along the Montana border. Temperatures support at least seeing some snowflakes down to around 4500-5000ft Thursday morning, but accumulations appear slim to none right now. If we can get a heavy band or showers to develop, we could see something brief stick to non-road surfaces. It will be breezy on Wednesday, although it appears we are falling below any wind-related thresholds. Heading to the Memorial Day weekend, look for some mountain showers Friday...with an increasing chance of precipitation Saturday and Sunday. Memorial Day itself MAY be dry. Our Blend of Models only has a few showers over the eastern and southeast highlands, as high pressure builds just to our west. That fits with about 75% of the cluster forecasts. Keyes && .AVIATION... We continue to watch a round of showers and isolated storms through this evening. The overall forecast should remain VFR with short drops below that with any heavier activity moving over a particular airport. We are carrying VCSH at all sites except DIJ and SUN. We left DIJ as -SHRA from before, and adjusted SUN to -SHRA VCTS. We should see everything diminish between midnight and sunrise. Keyes && .HYDROLOGY... Elevated river levels continue on the Portneuf River at Pocatello and Topaz. River levels are expected to gradually recede over the upcoming week but will likely remain high enough to warrant continued flood products for much of the week. McKaughan && .PIH WATCHES/WARNINGS/ADVISORIES... Frost Advisory from 3 AM to 9 AM MDT Tuesday for IDZ051>055. && $$