By this time next week, Manteca’s accumulative rainfall could exceed 20 inches since July 1.

And if it does, it will be almost 200 percent of normal.

The National Weather Service is forecasting upwards of 2¼ inches of rain could fall between today and Sunday on the Manteca-Ripon-Lathrop area.

Two storms are expected to hit Northern California with one today through Wednesday and the other Thursday through Sunday.

The heaviest for rain and snow will be the second storm.

It could drop between 1 and 2 inches on San Joaquin County and up to 3 inches on Sacramento and San Francisco.

In addition, 5 inches could fall in Sonora and another 4 inches in Yosemite Valley that is still closed due to excessive snow.

The same storm will see snow levels as low as 3,000 to 5,000 feet Thursday before rising to 6,000 to 8,000 feet on Friday.

Given the heaviest rain and snow is expected Friday in the valley and in the Sierra, the forecast calls for the potential for another 4 feet to fall on Sonora Pass on Highway 108, Ebbetts Pass on Highway 4 and Tioga Pass on Highway 120.

To give you an idea of what the continued snowfall means to the snowpack, Mammoth Mountain — just to the southeast Yosemite on the Sierra crest at 11,053 feet —  is expected to receive another 23 inches from the second storm just on Friday.

That would be added to the current snowpack that is at 308.7 inches in the upper Mammoth elevations — or more than 25 feet — and 223.6 inches in the lower elevations.

Mammoth typically enjoys the heaviest snowpack of all ski resorts in the United States with an average of 400 inches falling in a year. As such, in an average year they will operate into early July.

Mammoth Mountain is just to the southeast of the headwaters of the San Joaquin River at Thousand Islands Lake.

Today’s storm that will end in the early morning hours Wednesday might seem be a bit more spectacular although Manteca is expected to get no more than 0.25 inches of rain.

That is because the forecast calls for the possibility of isolated thunderstorms, lightning, small hail, brief heavy rains. And gusty winds from Redding south to Modesto as far east as Yosemite.

The timeframe for the most severe part of the storm is today between 11 a.m. and 7 p.m. depending upon the location in Northern California.

Snowfall will be less severe with up to 3 inches on Tioga Pass, 8 inches on Sonora Pass, and 18 inches on Ebbetts Pass.

As of Monday, Manteca has received 17.88 inches of rain since July 1. That is 176 percent of the normal rainfall of 10.18 inches.

For the year ending June 30, it is now at 133 percent of normal.

Typically, Manteca in an average year from July 1 to June 30 receives 13.45 inches of rain.

To contact Dennis Wyatt, email dwyatt@mantecabulletin.com