The National Weather Service in Sacramento reports that the hot streak torturing interior NorCal isn’t loosening its grip just yet, forecasting temperatures to soar into the upper 90s and even hit triple digits today. In response to the sweltering conditions, a Heat Advisory has been prolonged to last until 11 PM this evening, covering a significant swath from the Central Sacramento Valley to the Southern Sacramento Valley, including the Carquinez Strait and Delta regions, according to the National Weather Service.
As evening approaches, a faint sign of change appear on the horizon. The National Weather Service has indicated a very slight chance—between 5 and 15 percent—for some showers along the Sierra Crest, which could bring a modicum of relief. The real cooldown will begin Tuesday, spurred by a weak trough making its way through the area, which will introduce slightly lower temperatures combined with the Delta Breeze's return that evening.
Mid-week promises further relief, as Wednesday's forecast sees the oppressive heat begin to buckle, with high temperatures anticipated to just brush against 90 degrees—still hotter than usual for this time of year, but a welcome change from the days prior. Air moisture is expected to improve, offering daytime humidity values inching upward into the upper 20s to mid-30s percentile range.
By Thursday, the downward temperature trend continues, the National Weather Service predicts widespread 80s for the Valley, pushing us closer to the normal Fall temperatures we've been yearning for. The shift is thanks to a southward-moving trough in the Pacific Northwest that overpowered the ridge barrier responsible for the summer-like onslaught we've been facing.
A Pacific trough's expected arrival on Friday should usher in cooler, near-normal temperatures, before dipping slightly below normal on Saturday. Precipitation chances also emerge, with the northern Coastal Range potentially facing a 25-35% chance of seeing at least 0.10 inches of rain, while Sacramento Valley, the Delta, and the Sierra north of I-80 sit at a lower 15-25% probability. Breezy northerly winds could occur, but fire weather concerns are likely tempered by the trough-induced increased humidity levels, as reported by the National Weather Service. For aviation interests, Visual Flight Rules conditions are anticipated to sustain for the next 24 hours across interior northern California, keeping surface winds at bay under 12 knots.
