885 FXUS65 KPIH 070018 AFDPIHArea Forecast Discussion National Weather Service Pocatello ID 618 PM MDT Sat Sep 6 2025
.KEY MESSAGES...
- Thunderstorm threat expands to everywhere by early evening. Thunderstorm threat increases further on Sunday.
- Cloud cover and precipitation will bring a gradual cooling in both highs and lows today through Friday.
- Gusty wind outside of thunderstorms both this afternoon and Sunday afternoon.
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.SHORT TERM /THROUGH MONDAY NIGHT/... Issued at 133 PM MDT Sat Sep 6 2025
Afternoon satellite imagery shows continued hazy/smoky skies across much of eastern Idaho but a thicker cloud deck and precipitation moving in from the south is slowly pushing some of this smoke to the north. This should continue over the course of the day but I`d imagine we`ll still have a bit of lingering haze into the day tomorrow despite the increased clouds and precipitation. Speaking of the latter, hi-res models continue to show some scattered activity moving throughout the region into the evening hours. Not expecting a ton of precipitation from these, nor any real severe threat, but some beneficial rainfall is always helpful. Do have to look out for some lightning / fire starts and some occasional gusty winds from these storms however. Should get a bit of a break from the precip after midnight or so, although some lingering showers remain possible in spots overnight, before another day of widespread showers and storms look likely to round out the weekend tomorrow. Temperatures both days look to run right around seasonal norms.
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.LONG TERM /TUESDAY THROUGH FRIDAY/... Issued at 133 PM MDT Sat Sep 6 2025
Models remain in excellent agreement early in the week regarding inland shift of Pacific low. Most of Monday looks dry between shortwaves, but next onset of showers and thunderstorms look to arrive Monday night across the central mountains. The unsettled pattern begins in earnest beyond that time as the trough axis reaches the coast. Moisture continues to push into East Idaho around the upper low, with series of shortwaves providing focus for convection to develop. Ensemble clusters begin to show some deviation beginning Wednesday particularly with the depth of the trough as it shifts toward the Great Basin. Regardless of the details, the general scenario remains the same. Upper low continues to slowly track east through the week, ejecting in some manner to the east or northeast by the weekend. Unsettled conditions with continued cool temperatures are expected all week, trending toward drier by Saturday.
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.AVIATION /00Z TAFS THROUGH 24Z SUNDAY/... Issued at 618 PM MDT Sat Sep 6 2025
Smoke and haze will improve with system pushing through this evening and wind change direction. Scattered thunderstorms are possible through 3z this evening then clearing overnight. On Sunday a better chance for thunderstorms with all locations listed with PROB30s groups in the afternoon period. Gusty outflow winds will be possible with any of the stronger storms but otherwise the synoptic wind regime remains fairly light. Precip should taper off during the evening hours. VFR expected to prevail through the period outside of some brief, localized reductions associated with any convection.
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.FIRE WEATHER... Issued at 133 PM MDT Sat Sep 6 2025
First round of moisture to impact the East Idaho fire districts arrives today. Showers and a few weak thunderstorms already developing across western and southern portions of the forecast area. Storms will be primarily dry today though a few of the more zesty storms may be able to produce a very localized wetting rain. Model probabilities support a 30-40% chance of a wetting rain across the northern and southern Sawtooth NF areas, and the Bear River Range portion of the Caribou NF. Elsewhere, the chances drop off significantly to 20% or less, especially to the northeast where chances for thunder are much less.
A second shortwave pushes through on Sunday, but the threat for thunderstorms moves to the northeast with lesser chances for the southern zones. The best chances for wetting rains moves accordingly as well. Model probabilities for wetting rains support a 45-55% chance across all of Zone 411, the eastern half of Zone 476, and the northern portion of Zone 410 mainly bordering 411. The rest of the district supports a 10-25% chance of wetting rains for Sunday.
Drier conditions arrive for Monday between systems, but timing of the next feature may bring arrival to the central mountains Monday night for showers and an isolated overnight thunderstorm. That will begin a period of prolonged unsettled conditions through the remainder of the week with isolated to scattered showers and thunderstorms each day, cooler temperatures, and an early fall-like feel to the humidities.
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.PIH WATCHES/WARNINGS/ADVISORIES... None.
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SHORT TERM...McKaughan LONG TERM...DMH AVIATION...Preston FIRE WEATHER...DMH
NWS PIH Office Area Forecast Discussion