Area Forecast Discussion
Issued by NWS Pocatello, ID
Issued by NWS Pocatello, ID
898 FXUS65 KPIH 260926 AFDPIH Area Forecast Discussion National Weather Service Pocatello ID 326 AM MDT Sun May 26 2024 .SHORT TERM...TODAY THROUGH MONDAY NIGHT... A ridge of high pressure will build into the region for today and Mon, supporting generally dry, mostly sunny/clear conditions with decreasing winds. Those winds will stay breezy enough today, however, to support a LAKE WIND ADVISORY for American Falls Reservoir from 6 AM to 9 PM. Rough waves may be hazardous to smaller craft. Can`t completely rule out an afternoon shower or t-storm either up across the Fremont County area. Otherwise, highs in the upper 50s to upper 60s today gain 5-10 degrees for Mon topping out in the upper 60s to upper 70s. Spring is back. 01 .LONG TERM...TUESDAY THROUGH NEXT SUNDAY... Upper ridge begins to break down Tuesday as shortwave feature pulls moisture up into Idaho for a chance of thunderstorms. Tuesday should also be the warmest day with strong confidence of lower elevations daytime highs reaching very close to or well into the 80s. Upper trough shifts into the region by Wednesday, which should be the wettest and windiest day for Southeast Idaho. Ensemble clusters begin showing quite a bit of variation with progression of the trough by Thursday. Just under half of the clusters maintain amplified trough axis over East Idaho Thursday, with the other half trending toward a more shallow and slightly faster solution. The uncertainty continues into Friday, with about 30 percent of the ensemble solutions lingering the deeper trough over the region while the rest eject the trough northeast into the Northern Great Plains. 00Z deterministic ECMWF appears to follow the more amplified solution, but just a bit faster than the 12Z clusters, while the 00Z GFS appears slightly shallower over East Idaho. NBM deterministic means hold on to weak precipitation chances over the north into Friday, while beginning to trend temperatures up slightly. That said, overnight lows Thursday night could be cold enough to support hopefully the last of the Frost/Freeze headlines of the season. A lot can change between now and then. Moving into the weekend, the trend is for drier and warmer conditions as a ridge builds into the coastal states and shifts across the Great Basin. DMH && .AVIATION... VFR conditions are forecast for all sites as a ridge of high pressure builds into the region today. There is still a chance of very light -SHRA at KDIJ early this morning, lifting north of that terminal through the afternoon, but overall clearing is expected throughout the day for the rest of East Idaho. Winds become breezy after sunrise for the Snake Plain terminals KBYI/KPIH/KIDA, 15-20kts sustained. 90th percentile (1 in 10 chance of exceedance) winds could approach 25kts KPIH/KIDA. Winds diminish by 06Z tonight. DMH && .FIRE WEATHER... A ridge of high pressure builds into the region for today and Memorial Day Monday. There is potential for an isolated shower or thunderstorm across the northern portions of Zone 411 near the Divide today, otherwise expect dry conditions with a warming trend. Ridge begins to break down as early as Tuesday as a weak upper feature pulls moisture into the region, for a chance of thunderstorms mainly higher elevation areas. A trough of low pressure drives into the region for Wednesday and Thursday, but there is some uncertainty as to the depth of the system and how fast it clears out of Idaho. Wednesday should be the wettest and windiest day, but the cooler temperatures arrive for Thursday. There is a chance that the upper trough could linger into Friday, but the trend should be for drier conditions and a warming trend headed into the weekend. DMH && .PIH WATCHES/WARNINGS/ADVISORIES... None. && $$