The big chill coming from Canada on Wednesday threatens the San Joaquin Valley's broad citrus belt, but it also could mean the two-year drought will continue for a third season.
Steve Johnson, private meteorologist who forecasts for many growers, told me he sees a connection between the arctic express and drought years.
The arctic express of cold air drops night-time temperatures below freezing. Oranges, mandarins and lemons could be destroyed, and the citrus industry could be badly wounded this year.
But what about a third year of drought?
"This is also a potential disaster," Johnson said. "The correlation between drought years and extreme cold events is very high."
Fresno has 2.86 inches of rain this calendar year, according to the National Weather Service. The driest year I found in the data was 1947 at 3.55 inches.
Northern California reservoirs -- which hold irrigation for millions of acres as well as water for millions of residents -- are looking pretty anemic now. West Valley farmers are worried they will get a zero allocation from the federal Central Valley Project.
The two biggest freeze events in recent memory are 1990 and 1998. The citrus industry suffered more than $500 million damage in each of those years.
I remember restaurants and retail stores closing in small towns. There were food lines for months.
The 1990 freeze happened in the middle of a five-year drought. The 1998 freeze was sandwiched between two big rainfall years, but 1998 was sub-par for Fresno.
The biggest worry this week, though, is the dipping temperatures. If the temperature stays below 32 degrees for more than four hours, mandarins will be damaged. For oranges, the threshold is sub-28 degrees for more than four hours.
Wednesday through Saturday nights, the temperatures are expected to range between 22 and 27 in citrus groves.
Though the temperatures will be a few degrees higher in cities, such as Fresno, people should protect pets, plants and pipes, meteorologists say.