


Area Forecast Discussion
Issued by NWS Pocatello, ID
Issued by NWS Pocatello, ID
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533 FXUS65 KPIH 181917 AFDPIH Area Forecast Discussion National Weather Service Pocatello ID 117 PM MDT Sat Oct 18 2025 .KEY MESSAGES... - Our next fast-moving, generally low-impact storm system is expected to bring rain and snow showers, along with breezy conditions, Sunday afternoon through Monday morning. - Dry conditions are forecast for much of the week. - Next precipitation maker arrives next weekend. && .SHORT TERM /THROUGH SUNDAY NIGHT/... Issued at 117 PM MDT Sat Oct 18 2025 Dry conditions continue tonight as East Idaho remains under influence of dry northwest flow. Precipitation overspreads East Idaho Sunday, starting across the Frank Church as a mix of valley rain and mountain rain/snow around mid-morning. Front progresses through the region late Sunday into Sunday night. Ahead of the front, enough instability is present for isolated thunderstorm development across the eastern highlands. Snow levels begin falling behind the front late Sunday, progressing west to east, bringing snow down to around 5000 ft across the central mountains and Snake Plain, slightly higher across the southeast by late Sunday night. Did lower forecast Snow Levels slightly based on surface temperature progression through the night. Model QPF estimates rose slightly again with latest runs, resulting in higher snowfall amounts above 6500 ft. In general, however, accumulations remain light. The chances of seeing more than 4" of accumulation are highest along the spine of the Sawtooths and the higher elevations of the Frank Church and the Pahsimeroi range. Winds remain the only other concern as the shortwave pushes through Sunday. Sustained speeds across the Snake Plain look to range 25 to 30 mph with gusts 35 to 40, highest across the Arco Desert, where there is about a 25% for gusts to approach 50 mph. At this time will hold off on a Wind Advisory, but winds are expected to bump against the lower thresholds for a few hours in the afternoon across the northern portions of the Snake Plain. && .LONG TERM /MONDAY THROUGH FRIDAY/... Issued at 117 PM MDT Sat Oct 18 2025 Showers, including light snow at high elevations, should wrap up prior to noon on Mon except near the ID-WY border where it will linger into the afternoon. Skies will clear with upper level ridging continuing through at least Thu afternoon. At that time, an upper level trough will be moving through the eastern Pacific, trying to move onshore. It will take until Saturday for this low to set up on the coast and start ejecting short wave lows through the Pacific northwest and into the Gem State. Overnight lows will drop below freezing for all locations on Mon night. Lows bottom out on Tue night, then start to warm thanks to afternoon highs once again warming to above normal by Tue afternoon. Temperatures will even reach the 60s at low elevation in the Snake River plain and southern hills. Wind on Mon will be strong, possibly at Wind Advisory levels for the Snake River plain, maybe the eastern Magic Valley. However, wind will be over by Tue morning with light wind until Thu as the new low approaches. && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 1048 AM MDT Sat Oct 18 2025 A few cumulus this afternoon at KPIH and KSUN, otherwise it starts with high cloudiness in the early evening, then mid-level cloudiness developing over the late night hours. However, no CIGs are expected until after 19/18Z, so only KSUN has CIGs and VCSH in the TAF at this time. The more important forecast element is the wind. Light and variable conditions should start turning to the south and southwest, with wind increasing. Wind gusts of 25KT should develop around 19/17Z or around that time. KPIH with downslope wind may gust earlier. The same could be true for KBYI. && .FIRE WEATHER... Issued at 405 AM MDT Sat Oct 18 2025 After dry and mostly clear/sunny conditions today with drier afternoon humidity values, our next fast-moving storm system will bring rain and snow showers across the region from Sunday morning through Monday morning. Winds with this system continue to trend slightly stronger for Sunday afternoon and Sunday night, with many areas seeing gusts of 25 to 35 MPH (40 MPH over the Arco Desert region). Meanwhile, precipitation amounts instead of continuing to trend drier have increased just a bit, with wetting rain/snow looking especially likely across Zone 475, northern Zone 422, and along the immediate WY border corridor from Caribou County north into the Island Park region. Dry weather returns from Monday afternoon through much of the rest of the coming week behind this system. && .PIH WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...DMH LONG TERM...Messick AVIATION...Messick FIRE WEATHER...01