Updated: Monday, November 20, 2017 07:25 AM
The ridge of high pressure which gave us 2 days of fine autumn weather has been displaced by a weather system which has tapped into an atmospheric river out of the subtropics just south of Hawaii image right. This should bring about a change in the weather back to a wet pattern for the beginning of the week.
Skies have clouded up overnight and we have seen some light showers over Butte County, with only light accumulations before sunrise this morning, with this location only receiving 0.05" before sunrise. Temperatures have been running about 3° warmer than 24 hours ago, with a low so far of 44°. Winds have been very light overnight, with an occasional gust of only 1 mph.
Today should see mostly cloudy skies and a chance of rain throughout the day at varying odds. There is a more significant wave of energy dropping southeast through Northern California this morning, with the leading edge about at Red Bluff by 6:30 am. This area should increase the rainfall rates here in Magalia in an hour or two. There is an 85% chance of rain through about mid-morning, then the odds rise to a 95% chance as the aforementioned wave of energy near Red Bluff reaches our area. Odds drop back to a 65% chance by late this afternoon, and a 20% chance by late tonight. This system doesn't appear to be a gully-washer as only 0.50" or less rainfall is currently predicted in Magalia through midnight tonight. Temperatures are expected to be below normal (58°) this afternoon, with a high reaching 52°. The low tonight is forecast to only drop to about 50°. Winds may pick up out of the southeast today, reaching as high as 10 mph later this morning into the mid-afternoon hours. Winds begin to decrease tonight, becoming light and variable tonight. Snow levels should remain above 9500' to 10,000' today and tonight.
High pressure is expected to rebuild into our area and push the storm track back into the far northern mountains of California and Oregon for Tuesday into most of Wednesday, bringing back dry conditions. There is still a very slight 5% chance of showers on Tuesday, but appear to be highly unlikely. Odds drop to a 0% chance on Wednesday. We may also see a "Hot Spell" on Tuesday and Wednesday, with afternoon temperatures predicted at 63° and 68° respectively, and overnight lows in the mid-50°s. Winds should generally be light on both days. running about 3-6 mph during the daylight hours, and light and variable at night.
By Thanksgiving day, another weak weather system will push through the high pressure ridge and may increase the odds of precipitation by the morning hours, although the odds are somewhat low at that time at a 30% chance. The 30% chance looks to continue for much of the afternoon hours before dropping back slightly to a 25% chance late afternoon into the night. The high temperature on Thanksgiving is predicted at 61°, and the low that night near 52°. Winds should remain generally light on Thursday, along with snow levels above 10,000'.
Friday should see the holiday weather system exit the region, but a moderate chance of light showers could continue through the weekend as a moist southwesterly flow continues. Another weather system could bring a chance pf precipitation to our area late Monday or Tuesday. This system, looks to be more out of the northwest and could drop snow levels below mountain passes. Stay tuned, Bob