Triple degree heat for much of the Valley today and tomorrow, with lingering hot temperatures over the northern Sacramento Valley on Tuesday. Temperatures peak today with Valley highs from 100-112. Slight cool down by the middle of the week.
Discussion
Four Corners upper high extending northwest over California will bring hot weather this afternoon and Tuesday. High heat risk is expected this afternoon over the Northern Sacramento Valley especially over Shasta county near Redding where high temperatures near 112 degrees are forecasted. Record high for Redding today is 114 degrees, so readings will approach record levels.
Warm overnight lows are also expected from the mid 70s to near 80 degrees, mainly focused in the thermal belts and northern Sacramento Valley tonight.
A Heat Advisory continues for much of the Northern Sacramento Valley and surrounding foothills due to these conditions. Slightly cooler, but still hot conditions farther south over the Southern Sacramento Valley and Northern San Joaquin Valley where a slight moderating flow from the Delta will keep high temperatures in the 100 to 105 degree range with moderate heat risk.
Upper trough approaching the Pacific Northwest Tuesday will bring increasing southwest flow providing a slight cool down back into the 95 to 105 range for Valley locations. Upper trough will then pass through Oregon Wednesday further increasing southwest onshore flow with high temperatures falling back into the 90’s for most Valley locations.
A batch of monsoon moisture is projected to be lifted northward ahead of the trough, but it appears more likely that this moisture will remain largely east of the Sierra over Nevada. Can’t rule out a lone isolated thunderstorm near the crest over Alpine County Tuesday afternoon, but southwest flow will likely push any activity quickly east into Nevada.
Extended Discussion (Friday through Monday)
Ensembles and clusters keep Interior Northern California between Four Corner high pressure and troughing off the West Coast through the extended. This will keep seasonably hot temperatures over the area with periods of Delta breeze moderation over the Delta, Southern Sacramento and Northern San Joaquin Valleys.