Chris Fontana, "The Old Forecaster" 5/22/2013
We have had a high pressure area stuck along the west coast since the first of the year....Now as we move into summer it finally leaves. The mid and longer range forecast maps show low pressure troughs moving across the Pacific Northwest and Northern California through the first week of June. This means below normal temperatures for the next 10 to 14 days.
This morning's satellite picture (below) shows the cold low pressure area is over the Pacific Northwest. This system has cold air with it but not much moisture. Today and Thursday the north coast, Trinity, Siskiyou, northern Shasta, and Modoc counties will be partly cloudy during the afternoons and evenings with isolated light showers. Today the snow levels will be 5000 to 6000 feet but tomorrow will be over 6000 feet. Lassen, Plumas, and the higher elevations of Nevada counties will see a few clouds in the afternoon with the chance of an isolated light shower. The valley will stay sunny with a few afternoon clouds. Temperatures will be cooler with the far north 15 to 25 below normal and rest of the state 8 to 14 degrees below normal. Gusty southwest to northwest are expect this afternoon and evening and again on Thursday.
Friday the low will begin to move eastward. There will be a few clouds near the Oregon border with the chance of an isolated shower. Friday the rest of the north state will be sunny and warmer with temperatures rising to normal or a few degrees below.
Saturday another weak low pressure trough moves toward the west coast and will move across our area late Saturday and Sunday. (see map below). This system is not as cold as the current one but will have more moisture with it. Saturday afternoon and Sunday the foothills and mountains will be partly cloudy with a few light showers. The valley will see some clouds Saturday afternoon but should stay dry.
Monday looks sunny and warmer and then another weak low pressure area will bring more clouds and a chance of mountain showers Tuesday.