Stocktonians woke up to cloudy conditions and a stark change in temperatures Monday, a signal that the upcoming week will be remarkably cooler than the nearly summer-level heat that hit the Central Valley going into the weekend.
The National Weather Service even has a bit of rain and possible thunderstorms in the forecast over the next few days.
“This week is practically going to be the opposite of last week,” NWS meteorologist Scott Rowe told Stocktonia. “Where last week was warm and dry, this week will be cool and unsettled.”
Temperatures rose to around 90 degrees or higher in Stockton on Thursday and Friday, according to the weather service. However, Rowe says over the next four days the city will see temps in the mid to high 60s, first brought on by a marine layer pushing inland Monday and then by a relatively cold storm system for this time of year moving down the California coast starting about Tuesday.
The average temps for this time of year for the area typically sit somewhere around 79 degrees, Rowe said.
“We’re at a solid 10 to 15 degrees below normal for much of this week,” he said.
NWS says that some showers will likely spread over Northern California Monday afternoon and into the evening, with mountains seeing some snow.
It’s the storm system that will likely bring scattered showers to Stockton over the next two days, Rowe said, not the cloudy marine layer that moved into the Central Valley Monday. Though, he added that the upcoming precipitation will be nothing like what the area saw from January to March, which brought record-breaking storms and widespread flooding across the state.
“But still, if you’re driving, there may be a period of time where you may need to use the windshield wipers,” Rowe said. “If you’re inside and you miss it, you might miss it.”
The central Valley Tuesday could also see some isolated thunderstorms Tuesday, the weather service said.
Record-breaking snowfall and precipitation during the winter months in California may have brought a halt to the state’s pervasive, widespread drought conditions and contributed to a snowpack that was 260% of normal by April, but high heat at the end of last month have caused concerned that the state’s already overflowing river systems could be stressed even further that snow was melting too quickly.
In March, several areas of the San Joaquin River in San Joaquin County hit levels that were at or near flooding. Manteca and Lathrop were ordered to evacuate due to rising water levels following a series of high-precipitation storms. As of Monday morning, where the San Joaquin and Stanislaus rivers converge near the south county line at the unincorporated community of Vernalis is still classified as “Near Flood Stage.”
However, Rowe says the forecasted cooler weather could bring some reprieve to immediate flooding concerns. Areas of the Sierra Nevada could even see several inches of snowfall, he said.
“The rate of melting is going to be slower just because that’s tied directly to the temperature,” Rowe said.
Waterways that come through certain parts of the San Joaquin Valley, such as Stockton and Modesto, Rowe said, are largely affected by the releasing of water from reservoirs upstream when they get too full.
”The cooler the temperatures, the slower the inflow into the reservoirs. There’d be less water coming in at any given moment,” Rowe said. “As it gets warmer, you’d have higher rivers and mountain streams that would flow into the reservoirs.”
So this week’s temperature is going to halt some of that rapid melting, Rowe said.
In the meantime, Rowe says everyone should just enjoy the cooler weather this week while it lasts — which won’t be for very long.
“Summer will come back eventually,” he said. “The preview that we did see last week was short lived, but it certainly will be warming up eventually again.”