Sunday, January 1, 2017

Weather Discussion for Sunday January 1, 2017

Normal high and low temperatures for Dec 26-Jan 2 (high/low)...Redding 52/35, Chico 53/35, Quincy 44/23, Chester 40/20, Susanville 40/21, Grass Valley 51/31, Weaverville 45/29, Mt. Shasta 41/24, Yreka 43/25, Alturas 41/16

This blog will be issued every Monday morning and updated if the weather is changing or critical or interesting weather events are occurring.

Because of the incoming storms I will update this blog daily at least through midweek. 

Over the next several days we will shift from being in a cold relatively dry weather pattern to a warmer and wetter pattern.  This morning's satellite picture (below) shows the cold low pressure area sliding southward along the Pacific Northwest coast.  Further out in the Pacific you can see a series of low pressure areas and lots of clouds.   These systems and moisture are begin blocked from moving east by a high pressure ridge. The low pressure area will continue moving southward until it gets along the Northern California coast Monday afternoon.  It will then shift back to the west, which will weaken the high pressure ridge and allow the warmer moister airmass to mix into the the cold air associated with the low. (see map below). The timing of all this makes the forecast interesting...but here is how I think it will happen.

Today through midday Monday we will see partly cloudy to cloudy skies with snow flurries over the foothills and mountains.  The showers today will mainly from Redding northward but will spread down the Sierras tonight. The only area of the Sacramento Valley that will see showers today and early Monday is the area north of Red Bluff.  Snow levels today will be around 1000 feet but drop to 500 feet tonight.  Snow levels Monday will be 500 to 1000 feet north and 1500 to 2000 feet south.

Monday night and Tuesday the first surge of warmer moister air from the west reaches the coast.  This will make the precipitation more widespread and heavier, and will cause the snow levels to rise.   However, there will be a large area of cold air trapped over the north end of the state and until this is broken up or scoured our snow levels will remain low.  The snow levels south of Redding will rise to 5000 feet by Tuesday afternoon.  The area from Redding northward will continue to see snow levels 500 to 1000 feet until Tuesday afternoon or evening when they will rise to 3500 to 4000 feet.

Wednesday through the weekend a series of frontal systems will move across the north state every 24 to 36 hours.   These systems will bring more rain with snow levels around 5000 feet.   

The Old Forecaster

Click on images below to enlarge them...

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