The National Weather Service has issued an extreme heat advisory for Monday and Tuesday – didn’t it rain just a couple days ago? – with temperatures expected to nudge 100 degrees.

“Right now, our forecast for Monday is 99 degrees and 98 for Tuesday in Modesto,” said Sara Purdue, a meteorologist with the National Weather Service in Sacramento. “We had been getting influence in an area of low pressure, which typically brings low temperatures and potential for rain. Currently, we have high pressure building in the area. Thankfully, it’s trending eastward as it builds.”

Purdue said that growing high pressure system is expected to be centered over the Great Basin of Nevada and Utah, while the Central Valley will be on the edge of it.

“Beyond that, the high pressure starts to break down and we’ll see cooler temperatures on Wednesday,” said Purdue. “It depends on how much that high pressure area wants to move on or break down, but we should see a few degrees drop. And by Thursday, things should continue to drop into the (next) weekend.”

Typically, temperatures in the first week of May hover between the high 70s and mid 80s. And while temperatures in the upper 90s are rare, they are not unprecedented for this time of year. But just earlier this week, temperatures in the low 60s were accompanied by rain.

“This comes on the heels of the warmest or second-warmest winter since at least 1895 for a huge portion of the western U.S.,” said UC Merced climatologist Professor John Abatzoglou. “… (P)eople are not acclimated to the heat yet, as they would be in mid-summer, which increases the risk of heat impacts on human health. People who are sensitive to heat are advised to avoid being outside during the warmest hours of the day. Everyone should use sunscreen and stay hydrated.”

During the mini heatwave, the city of Turlock will open its cooling zones: the Turlock Public Library, 500 Minaret Ave., from 10 a.m. to 6 p.m., and the Roger K. Fall Transit Center, 1418 N. Golden State Blvd., from 6 a.m. to 9 p.m. Bus fares to cooling centers can be waived upon request during extreme heat events.

Other cooling zones in the region include:

• Denair Public Library, 4801 Kersey Road, from 10 a.m. to 6 p.m.
• Hughson Public Library, 2412 Third St., Suite A, from 10 a.m. to 6 p.m. (Tuesday only)
• Hughson Senior Center, 2407 Fourth St., 1 p.m. to 5 p.m.