A shift in the weather pattern is expected to bring isolated thunderstorms and cooler temperatures to the northern Sacramento Valley and surrounding areas this week, according to the National Weather Service.
Forecasters say there’s a 10% to 20% chance of thunderstorms through midweek, with greater potential arriving by Friday and Saturday.
“This type of thunderstorm activity isn’t uncommon for late April,” said Eric Kurth, lead meteorologist with the NWS in Sacramento. “We still see some thunderstorm potential this time of year — less typical than in March or February, but certainly not unusual.”
The change in weather is caused by a shift in pressure systems, Kurth said. A high-pressure system, which usually brings warm, dry and calm weather, is currently moving out. In its place, a low-pressure system from the Gulf of Alaska is moving in, bringing cooler air. Low-pressure systems tend to create more unstable conditions, which can lead to clouds, wind and thunderstorms — primarily in the afternoons and evenings.
“Today, we’re seeing highs in the mid-80s, which is about 9 to 10 degrees above normal,” Kurth said. “By Wednesday, we’ll drop closer to seasonal averages in the mid-70s, and by Friday and Saturday, temperatures could fall 5 to 10 degrees below normal.”
Some mountain areas may even see snow, Kurth said. Thunderstorms are expected to spread farther south by Friday and could reach as far as south Stockton.
Some residents are welcoming the cooler change. Valeria Núñez, a student at the University of the Pacific who commutes daily through south Stockton, said the drop in temperatures would be a relief.
“The heat is awful,” Núñez said. “Having some rain in the south area and a couple less degrees would definitely help.”
Still, she said she understands that the combination of dry weather and thunderstorms can be risky.
While some rainfall is possible later this week, Kurth says the system is not expected to bring widespread or long-lasting moisture.
Cooler temperatures will be the main story heading into the weekend, he added, along with the chance for isolated storms, especially in the northern part of the region. Looking ahead, forecasts say conditions are expected to dry out early next week, with temperatures gradually warming back to near seasonal norms.