FXUS65 KPIH 071054

AFDPIH



Area Forecast Discussion

National Weather Service Pocatello ID

454 AM MDT Mon Apr 7 2025



.KEY MESSAGES...



- Very high elevation snowfall the next 48 hours in the central

  Idaho mountains, light snow in the upper Snake River highlands



- Very windy conditions with blowing dust in the Snake River

  plain on Tuesday and Wednesday afternoons and evenings.



- Much colder Tuesday, with warming returning Wednesday.



&&



.SHORT TERM /THROUGH WEDNESDAY/...

Issued at 138 AM MDT Mon Apr 7 2025



Trough will swing through southern Idaho today and tonight, but

the trend in the southern half of the forecast area is for 

lesser snowfall with precipitation also trending lighter. Snow 

accumulation limited to areas in passes in the northeast 

highlands, and 8000ft elevation or higher in the central Idaho 

mountains. A second shortwave trough pushes through Tue/Tue 

Night, but there is even less of a threat of precipitation. By 

Wed, PoP currently runs down to zero or near-zero for the 

entire forecast area. 



Storm total rainfall doesn't get above 0.10 of an inch in the 

Snake River plain until north of Rigby. The main focus for 

rainfall will be in the western half of Custer County, including

the Wood River Valley and Stanley basin, where storm total 

amounts through Tue night are 0.10 to 0.30 in the valleys and up

to 0.80 of an inch in the mountains on the very western edge.

 

Even Galena summit will only receive 1 to 2 inches of snow with 

rain on either side of the snow period, so it is doubtful if 

much will remain with highs in the 40s both today and Wednesday.



There is a risk of thunder in the unstable air behind the front, but 

for today it will be limited to the western edge of the forecast 

area. On Tue, it will shift to the northeast corner, staying north 

and east of Roberts.



Expecting a warm day today, but the trough will bring in cold air 

and cloudiness, so expect a strong cool-down of 12 to 18 deg F to 

the afternoon high on Tue compared to Mon. The clear skies Wed will 

allow the return of warmer temperatures for the afternoon. 

Temperatures will get below freezing for the Snake River plain Wed 

night. 



Instability being forecast, the strong wind supporting the 

trough in the higher altitudes will be able to mix down both Tue

and Wed. This will likely mean Wind Advisories for the Snake 

River plain and possibly the valleys to the south of the Snake 

River. This includes a threat of reduced visibility in blowing 

dust--typical this time of year.



&&



.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...

Issued at 222 AM MDT Mon Apr 7 2025



High pressure will control the upper-level pattern again come 

Thursday, with models suggesting daytime highs will climb to 20 or 

more degrees above climatological norms across our lower valleys on 

Friday. We have blended the deterministic National Blend with the 

75th percentile to begin nudging highs closer to daily means on 

Thursday, Friday, and Saturday. Confidence is increasing in many low-

elevation areas across Southeast Idaho observing record-breaking 

temperatures during this period, especially on Friday during peak 

warmth.



The ridge axis will shift directly overhead on Friday and continue 

shifting eastward as the next upper-level trough works into the 

Pacific Northwest late week. Precipitation chances will reach 

southern Idaho on Saturday and likely persist through Sunday as the 

trough axis swings through. However, 500 mb ensemble clusters 

suggest much uncertainty in the upper-level setup come mid-weekend

into early next week, so confidence remains low in the forecast

through this timeframe.



&&



.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...

Issued at 452 AM MDT Mon Apr 7 2025



Mid to high clouds will increase beginning later today as a trough 

shifts inland. Previous timing of VCSH and -SHRA this afternoon and 

evening remains largely unchanged, with prevailing VFR CIGs and VIS 

throughout the period. Have again refrained from any mention of 

thunder with HREF indicating less than 20% chance of thunder at KSUN 

and KBYI and less than 10% chance elsewhere. Southwest winds will 

increase this afternoon, with 20 to 25 kt gusts forecast at KPIH, 

KIDA, and KBYI. Expect stronger winds Tuesday afternoon behind the 

cold front with less widespread showers.



&&



.PIH WATCHES/WARNINGS/ADVISORIES...

None.



&&



$$



SHORT TERM...Messick

LONG TERM...Cropp

AVIATION...Cropp