textproduct: Boise

LONG TERM...Sunday through Thursday

The main upper ridge will rebuild along the coast Sunday with warming again at higher elevations and the start of another inversion Sunday night through Monday. Models bring a weakening Pacific short wave trough through the ridge and inland Tuesday for a 20 to 30 percent chance of snow in northern zones Wednesday, followed by a stronger trough and 30 to 50 percent chance of snow Thursday, again in northern zones, although models have not verified well in the longer time ranges recently.

AVIATION

MVFR-IFR stratus in the valleys generally below 5000 feet MSL. Local LIFR near KTWF KJER KBNO until this afternoon. Surface winds VRB 10kt or less. Winds aloft at 10kft: W-NW 10-20 kt.

KBOI...MVFR ceilings continuing this morning/early afternoon, with some VFR possible in the afternoon. Surface winds light and variable under 6 kt.

Weekend Outlook...Areas of MVFR-LIFR low clouds and fog Saturday morning, clearing to VFR in the afternoon except near KTWF and KJER. Low stratus and fog will linger in the Magic Valley until Saturday evening before clearing. Surface winds NW 5-15kt Saturday afternoon. Sunday VFR with light winds.

AIR STAGNATION

Stagnant conditions will continue through Friday morning before a cold front mixes the atmosphere with breezy north-northwest winds. The main upper ridge will redevelop Sunday and Monday and begin another stagnation event, but a Pacific upper trough moving through the main ridge may break the stagnation Wednesday, with a stronger trough to follow Thursday.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Air Stagnation Advisory until 5 AM MST Friday IDZ011>014-016-028-033. OR...Air Stagnation Advisory until 5 AM MST /4 AM PST/ Friday ORZ061>064.