468 FXUS65 KPIH 091937 AFDPIH Area Forecast Discussion National Weather Service Pocatello ID 137 PM MDT Mon May 9 2022 .SHORT TERM...Tonight through Tuesday night. Early afternoon satellite imagery was showing a broad upper trough across the NW states with several disturbances cycling through the flow. One such disturbance was lifting into SW Montana and was supporting ongoing shower activity across the region. As a result, light to moderate accumulating snow is anticipated across the CNTRL and NE mountains through early this evening. Road reports currently show difficult driving conditions heading up into Island Park where a Winter Weather Advisory remains in effect until 8 PM. Across the Snake River Plain, Wind speeds remain at Advisory levels and are expected to begin tapering off between 6 and 8pm. By Tuesday, the next upstream disturbance, currently positioned along the Oregon coast, shifts SSE into NRN California leaving SE Idaho in a mostly drier SW flow aloft with the main forcing mechanism and shower activity focused across NRN California and NW Nevada through the morning hours. By afternoon, warming surface temps will support unstable conditions across SE Idaho and shower activity favoring the higher terrain across SE Idaho. The NRN California disturbance begins to shift SSE then east Tuesday night as it begins to eject into the Great Basin ahead of the next upstream disturbance migrating through the Gulf of Alaska. For SE Idaho, it means diminishing shower activity Tuesday night and then on to more interesting potentialities Wednesday/Thursday as the low lifts NE through the Great Basin (more on that below). Daytime temps remain below normal throughout the period even with the warming temps Tuesday afternoon. Huston .LONG TERM...Wednesday through next Monday. Cluster analysis shows good model consensus through much of the extended forecast. A closed low over Nevada will weaken and lift through the region Wednesday into Thursday. This will continue scattered showers across the region for those days. Although NBM 4.1 50th percentiles suggests that precipitation would be light and likely less than 0.10 inches. The pattern flattens out Friday into Saturday. Some light showers will remain possible on those days as the pattern transitions but chances for showers will be decreasing into the 20-30 percent range and mainly for the high country. A ridge is expected to develop over the region by Sunday and continue into Monday bringing dry weather to most of the area. Temperatures will remain about 5 to 10 degrees below normal for the rest of the week but will rebound to near normal on Saturday. Temperatures then climb above normal for late weekend and early next week with the 50th percentile NBM 4.1 supporting widespread highs in the 70s. 13 && .AVIATION...Convective showers resulting in VCSH into the early evening hours. Support for thunder looks very isolated and mainly confined to the high country of southeast Idaho so removed VCTS from TAFs although will monitor radar trends closely. Model consensus shows showers diminishing around 02z. Skies should clear for a time this evening with a mid level deck expected to arrive from the south late tonight or Tuesday morning. 13 && .PIH WATCHES/WARNINGS/ADVISORIES... Lake Wind Advisory until 8 PM MDT this evening for IDZ054. Wind Advisory until 8 PM MDT this evening for IDZ052-053. Winter Weather Advisory until 8 PM MDT this evening for IDZ066. && $$