textproduct: Boise

DISCUSSION

Dry air is moving in to the region this evening, with a few virga showers lingering in the Boise/West Central Mountains and patchy low clouds lingering in area valleys. These clouds might be enough to stave off patchy fog formation, depending on if they linger through the night. Current forecasts favor that they will dissipate by midnight, allowing for patchy fog to form in sheltered valleys through the early morning hours. Dry conditions with a slight warming trend will continue through the end of the work week with scattered precipitation anticipated by Sunday. No updates necessary to the forecast.

AVIATION

VFR except for patchy IFR/LIFR in fog developing overnight and continuing into Thursday morning. Surface winds: variable 10 kts of less. Winds aloft at 10 kft MSL: W-NW 35-50 kts decreasing to 25-40 kts after midnight.

KBOI...VFR. Surface winds: variable 5 kts or less overnight into Thursday.

PREV DISCUSSION

SHORT TERM...Tonight through Friday night...A weak cold front is currently pushing south and east through the region and should exit to the east by sunset. Scattered showers continue across southwest Idaho this afternoon, while drier air is already beginning to filter into southeast Oregon. Showers expected to dissipate by sunset. A transient upper level ridge will build from the west later tonight, leading to clearing skies. With recent precipitation and clearing conditions, patchy fog is expected to develop in the sheltered valleys early Thursday morning. Low temperatures tonight will be near seasonal normals, with lower valleys in the upper 20s to lower 30s and mountain valleys in the 10s and 20s.

Dry and stable conditions will prevail Thursday and Friday as the ridge shifts inland. Northwest flow aloft will keep temperatures slightly above normal by Friday afternoon. Breezy conditions are expected each afternoon, particularly in the Western Magic Valley and along ridgelines, with gusts reaching 20 to 30 mph.

LONG TERM...Saturday through Wednesday...An upper-level trough will move into the OR/CA border region Saturday morning, bringing southwest flow aloft. Shower chances increase from SE Oregon, beginning late Saturday morning into afternoon, and move into SW Idaho Saturday afternoon into evening. Precipitation chances will persist through Monday afternoon until the system moves further SE of the region, with chances around 30-50% areawide. Snow levels range from 5000ft near Baker City and McCall, to around 7500ft near the NV border with this system. Behind this system, upper-level ridging will build back into the area. This will bring spring-like temperatures, with valleys reaching the low to mid 60s on Tuesday or around 10-15 degrees above normal. Ensembles hint at a cold front moving through the area late Wednesday, with snow levels lowering to around 4000-5000ft and light snow accumulations over the mountains.

BOI WATCHES/WARNINGS/ADVISORIES

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