Area Forecast Discussion
Issued by NWS Pocatello, ID
Issued by NWS Pocatello, ID
284 FXUS65 KPIH 270852 AFDPIH Area Forecast Discussion National Weather Service Pocatello ID 252 AM MDT Mon May 27 2024 .SHORT TERM...Today and Tuesday Pleasant weather expected for your Memorial Day across eastern Idaho as high pressure continues to amplify over the region. We should see mostly clear skies, light winds with temperatures near seasonal norms. This means lower to middle 70s across the Snake Plain and Magic Valley with mountain zones in the mid to upper 60s. Hi-res CAMs show basically very little chance of see any precip today and the forecast agrees accordingly. On Tuesday, we`ll see widespread 80s for the first time this year as high pressure reaches it`s maximum intensity over the area around mid day. Lower 80s will likely be realized into the upper Snake Plain and certainly into the lower Snake and Magic Valley. Mountain zones will see lower to middle 70s as well so certainly one of the warmer days we`ve seen in quite some time. A trough will begin to dig into the Pacific NW during the day and this feature should help to reintroduce PoPs back into the forecast during the afternoon and evening hours. Coverage looks scattered in nature with best coverage likely across the central mountains. Given the warm temperatures, thunderstorms can be expected some of which could be strong. The Storm Prediction Center has a "marginal risk" designation sneaking into the the northwestern most portion of the CWA (around Stanley) but we`ll see how hi-res guidance handles things over the next 24-36 hours. McKaughan .LONG TERM...Wed through Sun night Clusters indicate an low confidence forecast, if you need completely dry conditions. The first day has a trough approaching from the west, but has not yet reached the forecast area really by Wed afternoon. For Thu, the guidance is split evenly between solutions that keep the trough either farther north (not much of a factor) and overhead (wetter, more unstable, cooler). Some solutions slow down the eastward movement for Fri, but they are a minority with most having moved the trough far enough east to warm and dry. By the coming weekend, an upper level ridge axis is over eastern Idaho; it`s just a matter of how amplified the axis is. Only 14 percent have a low- amplitude trough over the northern portions of the forecast area on Sun afternoon. So would expect a dry and warm weekend. Temperatures are knocked back down on Thu with the trough, with widespread afternoon highs in the 60s, even in Stanley. Conditions are slow to warm with a west northwest airflow, but stronger warming finally kicks on the weekend, with afternoon highs in the 70s for the lower elevations in the Snake River plain/eastern Magic Valley, to the potential for reaching 80 degrees at lower elevations on Sun. Even Thu night should have low temperatures above Frost Advisory thresholds. The approach of the trough indicates Wed late afternoon to evening to have solid chances of reaching Wind Advisory conditions, and breezy to windy conditions Thu. Fri through the weekend appears to be much calmer. Messick && .AVIATION... VFR conditions expected through the forecast period with high pressure in control across the region. Winds will be much lighter today, generally 10 knots or less, throughout the day. Skies will be mostly clear allowing for near perfect flying conditions throughout eastern Idaho. McKaughan && .FIRE WEATHER... Dry and sunny conditions through Wed means that temperatures will finally feel summer-like on Tue as many of the lower elevations should be crossing the 80-degree F threshold that afternoon, for the first time since 2023. Until Tue, minimum humidity should stay in the upper teens and 20s, even higher in the eastern highland mountain tops. With the approaching trough, the humidity spikes upward for both Wed and Thu. Very windy conditions are possible with this trough on Wed prior to its arrival. Thunderstorms will be around for Tue and Wed with strong outflow winds possible over the Salmon-Challis NF both days. Messick && .PIH WATCHES/WARNINGS/ADVISORIES... None. && $$