textproduct: Pocatello

KEY MESSAGES

- Unsettled conditions return Monday and Tuesday.

- Lake Wind Potential Tuesday.

- Another round of Frost/Freeze Wednesday AM.

DISCUSSION

Issued at 1252 PM MDT Sun May 3 2026

Satellite imagery shows split flow pattern with deep low off California coast and shortwave dropping through Montana in northern stream flow. There is still a low chance of seeing isolated convection this afternoon across higher elevation areas, but surface dew point depressions are quite low. Confidence leans toward virga showers with an occasional sprinkle this afternoon and early evening. Split flow collapses slightly into Monday as coastal low shifts inland slightly and starts to open, allowing moisture to pull north into East Idaho. Thunderstorm activity increases, especially across the southern highlands. Sounding profiles look favorable for gusty winds with potential for brief moderate rainfall, though most areas will see little precipitation.

Shortwave feature for Tuesday drops frontal boundary south across the forecast area early in the day. Showers and isolated thunderstorms continue mainly over higher terrain. Slightly cooler temperatures and gusty northerly flow will be in place. For winds, blended above NBM deterministic towards the 75th percentile, keeping forecast below general Wind Advisory criteria. But, a Lake Wind Advisory will likely be needed for American Falls Reservoir, with rough chop piling up at the south end near the dam under the influence of the northerly winds. Another night of frost/freeze is looking more confident as NBM probabilities support more than 50% chance of overnight lows dropping below freezing for the northern portions of the Snake Plain Tuesday night/Wednesday morning. It does look like a one- and-done cold snap as upper ridge rebounds for the remainder of the week with a return to a warming trend and a greater than 50% chance of several areas meeting or exceeding 80 degrees for highs by Friday. GFS and ECMWF models this morning continue to show shortwave pushing through the PacNW and across Montana late Friday into the weekend, collapsing the ridge and reintroducing unsettled conditions to East Idaho for the weekend.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

Issued at 504 PM MDT Sun May 3 2026

Some -SHRA developing in the central Idaho mountains southeast highlands, and northeastern highlands. Should not be a factor in terms of bringing impactful weather to either KSUN or KDIJ. Meanwhile, the other three airdromes should be unaffected by the activity. CIG development limited to 8000ft AGL and above for the entire period. No impact foreseen for VSBY. For Mon afternoon and evening, TSRA is possible at KSUN as approaching trough increases the wind for Mon, along with SHRA around the area. Used PROB30 group as the around 5 percent chance risk for 5 hours just barely exceeds 25 percent chance.

Wind continues more or less light and variable, with some moments getting into the 10KT-15KT range for KIDA, KPIH, KSUN, and KDIJ. Directions are not very consistent, even when speed exceeds 8KT. TS outflow for KSUN could reach G30KT as indicated by HRRR showing a storm cell putting out that kind of wind in the Wood River valley where KSUN is.

PIH WATCHES/WARNINGS/ADVISORIES

None.