900 FXUS65 KPIH 110836 AFDPIHArea Forecast Discussion National Weather Service Pocatello ID 236 AM MDT Thu Sep 11 2025
.KEY MESSAGES...
- Gradual cooling trend starts today, warming returns Monday.
- Isolated to scattered showers and isolated thunderstorms today through Sunday afternoon.
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.SHORT TERM /THROUGH TONIGHT/... Issued at 230 AM MDT Thu Sep 11 2025
Early morning radar shows showers continuing to lift out of Utah. High resolution models show activity continuing over the next several hours, dissipating from south to north prior to sunrise. There is a 20% chance of lightning through then, with the eastern highlands the most likely region to observe it. The next round of convection will begin in the early afternoon and continue through late evening, with the western half of the CWA being the favored corridor from the South Hills north into the central mountains. HREF indicates a 20 to 70 percent chance of thunderstorms across the central mountains (chances increasingly higher further north), a 20 to 60 percent chance in south central Idaho with greatest chances further southwest, and a 10 to 30 percent chance across much of the remainder of the CWA. Storms will be capable of producing small hail and gusts to 40 mph with locally stronger gusts possible. Daytime temperatures today will run 5 to 10 degrees cooler than yesterday, with highs in the low to mid 70s in our valleys and 50s and 60s in the mid- to high elevations. Conditions look to remain mostly quiet overnight tonight as the trough axis swings through Idaho, although a few showers are likely for the central mountains and east and southeast highlands.
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.LONG TERM /FRIDAY THROUGH WEDNESDAY/... Issued at 139 PM MDT Tue Sep 9 2025
As we head into the weekend, troughing looks to still be in place over much of Eastern Idaho. This will keep our unsettled weather pattern going with rain and thunderstorm chances continuing for Saturday and Sunday. However, we may be a bit drier on Sunday as a weak ridge passes through our area ahead of a low pressure system moving into the Pacific Northwest early next week. Temperatures will be quite mild on Saturday (dare I say even "cool"?) with highs in the 60s and low 70s for most. The slightly drier conditions as the ridge moves through on Sunday will help us all warm up a few degrees for Sunday afternoon after starting the day in the 40s. Highs for the first half of next week are forecast to remain in the low to mid 70s. Also in the first half of next week, we see some varying model solutions to handling a trough moving onto the West Coast. The ECMWF swings a trough through Washington and northern Oregon on Sunday before moving and lifting northward and developing a low in northwestern Montana late Monday. This solution keeps some high elevation precipitation chances in the forecast for the Central Mountains and Eastern Highlands early next week. The GFS on the other hand is the wetter solution as develops a deeper low over Oregon on Monday that moves eastward through Idaho on Tuesday. Both models agree on drying out a bit by the middle of next week. We will have to watch and see how models evolve over the next few days.
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.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 1008 PM MDT Wed Sep 10 2025
A few showers with isolated thunderstorms will move north through the eastern highlands tonight resulting in a PROB30 at DIJ for -TSRA. Other locations should remain quiet. Think activity will remain east of IDA/PIH. Expect redevelopment Thursday afternoon with at least a 30 percent chance of storms at all locations.
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.FIRE WEATHER... Issued at 127 PM MDT Wed Sep 10 2025
Not much thunderstorm activity expected this evening, mainly limited to mountain areas in isolated coverage. The risk of showers and thunderstorms increases over the next couple of days, but won`t be getting much higher than isolated coverage for thunderstorms and scattered for showers. With temperature at Snake River plain elevations cooling into the 70s through the weekend, and perhaps even upper 50s, it will be hard to get humidity to dry to below 15 percent. Gusty wind this afternoon in some locations should end early in the evening and is not expected to return Thu or Fri.
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.PIH WATCHES/WARNINGS/ADVISORIES... None.
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SHORT TERM...Cropp LONG TERM...AMM AVIATION...13 FIRE WEATHER...Messick
NWS PIH Office Area Forecast Discussion