068 FXUS65 KPIH 131721 AFDPIHArea Forecast Discussion National Weather Service Pocatello ID 1121 AM MDT Sat Sep 13 2025
.KEY MESSAGES...
- Cooler temperatures continue into early next week.
- Isolated showers and thunderstorms also continue, mainly over higher terrain.
- Drier and slightly warmer pattern for mid to late next week.
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.SHORT TERM /THROUGH SUNDAY NIGHT/... Issued at 149 AM MDT Sat Sep 13 2025
Radar this morning shows a few showers along our borders with MT and WY. Any lingering showers will likely conclude around sunrise or shortly after. Outside of these few nocturnal showers along the periphery of our CWA, conditions will largely remain quiet ahead of isolated showers and thunderstorms this afternoon. High resolution models show convection initiating shortly after Noon today. Convection will again be focused along the high terrain, with the best chances for thunderstorms being in the east and southeast highlands. Storms will be capable of producing small hail and gusts 30 to 40 mph. Showers and storms over Southeast Idaho will largely diminish by around 9 PM tonight with little support for any overnight activity tonight. Daytime temperatures today will be just a touch cooler than yesterday`s highs, running in the low to mid 70s in our valleys and 50s and 60s in the mid to high elevations.
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.LONG TERM /MONDAY THROUGH FRIDAY/... Issued at 133 PM MDT Fri Sep 12 2025
On Sunday, a transient ridge of high pressure is moving across Idaho with mostly dry conditions through at least the first half of the day. This ridge will allow temperatures to warm into the mid and upper 70s in the afternoon. In the second half of Sunday, this ridge will be exiting Eastern Idaho as an area of deep troughing begins to develop a low over central Idaho. This next system will bring rain chances back to the Central Mountains as early as Sunday afternoon/evening and then showers will spread eastward overnight into Monday. Highs on Monday will be running about 5 to 10 degrees below normal with many in the mid to upper 60s. Looking at the 48 hours from Sunday morning to Tuesday morning, the NBM shows about a 10 to 25 percent chance for at least a tenth of an inch of rain in the eastern Magic Valley and Snake River Plain. Those numbers increase to about a 30 to 50 percent chance in the Central Mountains and Eastern Highlands and even a bit higher to around a 60 percent chance up in the Island Park area. Winds gusts will increase a bit on Sunday and Monday, too, to around 20 to 25 mph each afternoon. We will dry out from west to east on Tuesday as this system departs and high pressure begins to build back in over the area. Highs on Tuesday will be just a couple of degrees warmer than Monday, but the warmer weather makes a return with high pressure on Wednesday, warming into the mid and upper 70s. Expect highs to be very similar on Thursday.
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.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 1121 AM MDT Sat Sep 13 2025
Storms look to be even more isolated in nature this afternoon than the last few days. So, while a shower or storm may pass near a terminal, confidence is low in a direct impact. Will include some VCSH in the TAFs for DIJ and SUN, but that`s all for the time being. Otherwise expect VFR conditions today and Sunday. Winds remain light through the rest of today and tonight. Look for clear skies tonight before our next round of cloud cover begins to move in Sunday morning ahead of our next system.
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.FIRE WEATHER... Issued at 133 PM MDT Fri Sep 12 2025
Upper low moving over East Idaho today, with trough axis shifting east into Wyoming for Saturday. Rounds of isolated to widely scattered showers and thunderstorms will continue each afternoon and evening. A few showers will be possible overnight tonight across the Caribou-Targhee NF, though confidence is low. Unsettled conditions continue into early next week as a new system works across the region. Temperatures remain cool through early next week, with Monday and Tuesday the coolest days of the week for most. A ridge of high pressure looks to build back into the region for mid to late next week, with a slight bump in temperatures back toward seasonal normals.
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.PIH WATCHES/WARNINGS/ADVISORIES... None.
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SHORT TERM...Cropp LONG TERM...AMM AVIATION...AMM FIRE WEATHER...DMH
NWS PIH Office Area Forecast Discussion