Sunny skies. Climate science. And a dry December in Stanislaus County.

The Northern San Joaquin Valley is dry this month. While there is no reason to panic about the dry conditions, water experts are paying attention to the lack of rain.

Modesto has received zero inches of rain for the month and may not get any sprinkles from meager storms that move down the coast of California later this week. It's still possible residents will have no need for umbrellas the rest of December.

According to historical records, a rain-free December has never happened before in Modesto.

“We might get a few weak storms Wednesday and Thursday,” said Chris Hintz, meteorologist for the National Weather Service office in Sacramento. “The precipitation may get down as far as Modesto but it is going to be really light.”

December is the usually the second wettest month for Modesto, which makes the current dry period especially odd.

According to the Modesto Irrigation District, which has been recording Modesto rainfall since 1898, Decembers 1999 and 1989 saw just one day of rain – with each tying a record-low total for that month of 0.01 inches.

There have been six Decembers with just one day of rain, the most recent in 2013, which saw 0.28 inches fall.

Mother Nature nearly pitched a shutout in 1930 when the month's first drop didn't fall until New Year's Eve. Last December, the MID recorded 2 inches in downtown Modesto.

This fall, Modesto received seven tenths of an inch in October and November combined and total precipitation is 15 percent of normal for this time of year.

Though the weather conditions could change, it is stacking the deck for a dry year in the San Joaquin Valley. (Rainfall is measured over an official season from July to June.)

"I don't see this pattern changing any time soon," said Professor Noah Hughes, who teaches meteorology at Modesto Junior College. "My hunch is we are going to end up being below normal for the year."

Hughes said the current conditions look like the extended dry periods that occurred in the 2012-2016 drought, which was one of the worst on record. And that's why water watchers are paying attention.

During those years, the dry weather was caused by especially strong atmospheric ridges that parked off the West Coast. Those ultra-strong ridges continually pushed storms to the north into Canada and deprived California of rain and snowpack in the Sierra.

Hughes said a similar ridge of high pressure has kept the valley dry since the last rainfall Nov. 21, when two tenths of an inch fell on Modesto. That has renewed talk of potential water shortages down the road, just eight months after Gov. Jerry Brown signaled an end to the previous drought emergency.

"It's scary now, because we are not seeing rain. We are not seeing any (Sierra Nevada) snow, " said William Wong, acting director of utilities for Modesto, who discussed city wells at Tuesday's City Council meeting.

Half the city’s water supply is Tuolumne River water treated by the Modesto Irrigation District.

“The fortunate thing is our reservoirs are full,” Wong said. “But we still have a lot of competing interests for the water. … Hopefully, this dry period is just a fluke.”

Turlock Irrigation District is keeping an eye on the weather, and a spokesman said there is still time to make up any deficit.

Don Pedro reservoir, which opened its flood gate in February, has plenty of storage carried over from the heavy storms of last winter.

“Although December has been dry so far, we still have a lot of potentially wet periods ahead,” TID's Calvin Curtin said in an email. He noted that January through March are peak rain and snow producers.

The drought that officially ended earlier this year ― marked by depleted reservoirs and failed wells ― cast more attention on multi-year dry spells in California.

Hughes said a recent spate of research articles have pointed toward longer-term dry conditions in California, some related to global climate change.

In a study published this month, researchers at Lawrence Livermore National Laboratory showed that the loss of Arctic sea ice could be causing dry weather patterns in California.

The study revealed a connection between Arctic ice loss and atmospheric ridging over the northern Pacific Ocean.

"The pattern we are seeing this month in California is exactly what climate scientists are connecting to decreases in Arctic sea ice. And sea ice extent this year was the third lowest on record," Hughes said. "We can expect more of this in the future."

Climate change and the prospect of water shortages in Northern California are among the reasons why Stanislaus and other counties are working on a strategy for conserving and recharging groundwater.

Stanislaus County Supervisor Terry Withrow offered a reminder that California voters approved a state water bond in 2014 that was supposed to increase storage capacity in reservoirs. But not much has happened.

“What is really discouraging now is they are making room in the dams for the winter rains that are coming,” Withrow said. “They are letting water go, and if that rain does not come, it is tough to get that water back.”

This story was originally published December 16, 2017 at 5:43 PM with the headline "Sunny skies. Climate science. And a dry December in Stanislaus County.."