February 2, 2020 – A weak Pacific trough will bring cooler conditions and light precipitation to the region today. Breezy northerly wind develops with this system and persist into early Tuesday. Dry conditions expected throughout much of next week.
Discussion
The weak upper level trough is advancing towards the coast this morning which has brought high clouds to the region. Overall, in terms of precip, this system is pitiful. Majority of the rain will likely fall in the foothills, where they may be able to squeeze out a few hundredths of inch. Higher up in the Sierra, QPF amounts range from 0.05 to 0.30 inches. Snow levels for this system will start around 4000 to 4500 feet before tanking as the cold front pushes through. Expect to see 0.25 to 5 inches of snow accumulation for elevations above 3500 feet, with the greatest amounts accruing over 4500 feet.
The more interesting part of this storm will be the winds and colder weather it brings with it. As the trough slides in from the northwest, it will dig and deepen as it moves into Nevada. This means we’ll see a decent uptick in winds, as they take on a northerly component. Look for northerly winds to be around 20 to 30 mph with gusts up to 30 to 45 mph for the Valley, generally from late morning through the overnight hours. In addition, breezy north to northwest mountain winds with gusts up to 50 to 60 mph over the higher terrain could cause periods of blowing snow and difficult driving conditions at times. Highs for the Valley today will span the low to mid 50s while the foothills and mountains top out in the 30s and 40s.
As we head into Monday, expect even cooler temperatures across the area. Morning lows and day time look to be 5 to 15 degrees below the seasonal average. The morning will start off somewhat chilly, and in the 30s for the Valley, while the foothills and mountains range from the single digits to the 30s. We’ll warm decently, but still be cool and breezy with highs peaking in the upper 40s to low 50s for the Valley. The northerly winds shouldn’t be as potent as they were on Sunday, with the Valley seeing sustained winds around 15 to 25 mph. Gusts up to 35 mph will be possible there, with stronger winds expected for the higher elevations.
Cool conditions persist into Tuesday, but the winds will quieting down. The trough will continue to push eastward allowing for ridging to build behind it. Expect dry weather through the middle of the week.
Extended Discussion (Thursday through Sunday)
Another stout upper ridge moves into the picture by the middle of next week. Based on a comparison to climatology, 500-mb heights should be around 2 standard deviations above average. This will ensure another period of dry, mild weather with temperatures rising throughout the week. By the conclusion of next weekend, global ensembles continue to indicate the approach of a longwave trough with great uncertainty surrounding this system. While it could bring some precipitation, there is also a chance for more gusty winds depending on the track. Until the models come into better agreement, the uncertainty will remain low.