textproduct: Boise

DISCUSSION

The weak system off Calif near 40/130 will move ENE-ward into our southern zones later today and tonight, away from the parent upper low near 40/130. It will still be strong enough for scattered showers and isolated late-day thunderstorms in Harney and Malheur Counties. The system will weaken further Sunday as it tracks eastward across southern Idaho, but still moist enough for showers and a slight chance of PM thunderstorms. Daytime temps will continue 5 to 10 degrees above normal for late February, lowering about 5 degrees under clouds and showers. Light winds, except outflow gusts 30-40 mph ahead of stronger showers and thunderstorms. Current forecast on track. No updates.

AVIATION

VFR with increasing clouds as showers develop across SE OR and SW ID this afternoon. Snow levels rise to 7-8 kft MSL, with VFR-MVFR ceilings, mtns obscured, and a 10% chance of lightning near the NV border this afternoon. Surface winds: variable 5-15 kt. Winds aloft at 10kft MSL: W 10-25 kt.

KBOI...VFR and a less than 10% chance of precipitation this afternoon. Wind stays light and variable, favoring NW this afternoon.

Sunday Outlook...Showers expanding northward Sunday. MVFR-IFR developing in mtn snow and heavier rain showers with snow levels 6-8 kft MSL. Another 10% chance of afternoon lightning in SE OR and along the NV-ID border. Surface winds: SW-SE 5-15 kt, gusts up to 30 kt with storms.

PREV DISCUSSION

SHORT TERM...Today through Monday night...A weak system off the CA coast will slowly track inland with increasing clouds this afternoon. Scattered showers (30-50% chance) develop in SE Oregon late this afternoon with slight chance (10% chance) of thunderstorms along the NV border. Showers weaken overnight with the loss of daytime heating, but reform again during the afternoon, with a slight chance of thunderstorms (10-20% chance) mainly over eastern OR and south of the Snake Basin in ID. Snow levels range from 7000-8000ft with this system. Minimal snow accumulations expected over the mountains. Showers and thunderstorms Sunday and Monday afternoon have the potential to produce gusty outflow winds up to 30-40 mph.

LONG TERM...Tuesday through Saturday...Upper level ridging returns on Tuesday ahead of the next system. Temperatures Tuesday will be the warmest of the period, with mid 60s possible across the Snake Basin, or around 10-15 degrees above normal. Ensembles bring a potent cold front through the area on Wednesday afternoon, with snow levels falling to 3500-4500 feet by Thursday. Snow showers continue over the higher terrain Thursday with the cold unstable air aloft. Conditions dry out on Friday between systems. A return to cool and unsettled by the following weekend with moist northwest flow expected and temperatures slightly below normal.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None. OR...None.