textproduct: Boise

DISCUSSION

Showers are slowly tapering off over most of the region this evening. As of 8:30 pm MST, 0.53 inches of rain has fallen at the Boise airport, with Deadwood Summit in the West Central Mountains (elevation of 7000 feet) reporting 8 inches of snow. Showers will linger overnight, with snow levels dropping from 7000 feet MSL this evening to 4000-5000 feet MSL Wednesday. Temperatures will remain slightly above normal tonight and tomorrow, with colder overnight lows below freezing expected by Thursday morning. Breezy winds will return for ridgetops and the Lower Snake Plain, with gusts up to 40 mph near Twin Falls- Jerome tomorrow afternoon. The forecast has been updated to increase wind speeds and gusts through tomorrow afternoon with higher confidence in increased winds from recent hi-res model runs.

AVIATION

Widespread precipitation will continue to move and exit to the east through the evening. Scattered showers will persist across the area through Tuesday. MVFR/LIFR Ceilings will lift to VFR by Wed/AM. Snow levels: 6-8kft MSL, lowering to 3-8kft MSL by Wed/PM. Surface winds: SW-SE 5-15 kt, becoming W-NW 5-15 kt Wed/AM except 10-20 kt with gusts to 20-30 kt near the w-Magic Valley & KBNO. Winds aloft at 10kft MSL: W 30-45 kt.

KBOI...VFR. Ceilings continuing to lift overnight. Scattered showers could impact terminal (30% chance) overnight into Tue/AM. VFR conditions expected. Surface winds: SE 5-10 kt, becoming NW 5-15 kt by Wed/18z.

PREV DISCUSSION

SHORT TERM...Tonight through Thursday night...Rain and high- level snow continue to stream across our CWA but a cold front from the northwest will carry most of it eastward out of our CWA overnight through Wednesday morning. Light rain and mountain snow will decrease Wednesday then end in all areas Wednesday night. Snow levels will highest this evening, ranging from 6000 feet far north to 8000 feet along the NV border - just before the cold front comes in, then lower overnight through Wednesday. By late Wednesday afternoon snow levels will range from 3500 feet north to 6000 feet near the Nevada border. Storm total QPF and snowfall through midday Wednesday have changed little from previous forecast. The main story Wednesday will be post-frontal west winds in southern Idaho. Speeds will increase to near advisory levels in south- central Idaho midday Wednesday, but stronger in eastern Idaho. We have decided to not issue a Wind Advisory for our CWA. Winds will decrease Wednesday evening and clouds will decrease later Wednesday night allowing temperatures to finally cool to normal for late February. Patchy fog will form in the valleys early Thursday morning.

LONG TERM...Friday through Tuesday...Northwest flow aloft associated with an upper-level ridge axis just offshore of the Western CONUS will create dry and clear conditions Friday. Breakdown of this ridge occurs late Friday into Saturday with the intrusion of an upper-level low embedded in the flow moving into the CA/OR region. This will cause flow aloft to shift to westerly/southwesterly ahead of the low, slinging some moisture into the region. PoPs begin to increase midday Saturday and stay populated until late Monday as the upper-level low moves south/southeast from Northern California. Greatest chance of precip are Saturday evening to Sunday morning at 30-50%. Snow levels will range from 5000-7000 ft MSL, but precipitation amounts will be light. Another upper-level ridge builds in as the low moves out. Above normal temperatures will persist through the pattern, with valleys reaching the low to mid 60s on Tuesday and Wednesday, or around 10 degrees above normal.

BOI WATCHES/WARNINGS/ADVISORIES

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