Keep your umbrella handy. You’ll need it over the next few days

Weeks of dry weather ended Monday with rounds of heavy showers and thunderstorms that left the Rock Hill area under a flash flood watch into Tuesday morning.

The National Weather Service said clusters of heavy storms – like those that rumbled northward across the region late Monday afternoon – are possible into Tuesday.

The stormy weather is being fueled by a large upper-level low pressure system that is forecast to affect the area into midweek.

About a half-inch of rain fell Monday morning and another half-inch was reported in the late-afternoon with a second round of storms. That area of thunderstorms was responsible for a tornado warning in Gaston County after the system pushed northward out of York County.

Meteorologists at the National Weather Service office in Greer said any of the storms could dump rainfall at rates of up to two inches per hour. Forecasters were not sure if the heavy rain threat would continue into Tuesday.

The Weather Service’s Rodney Hinson said Monday evening that computer guidance is sending mixed signals on whether the amount of moisture in the atmosphere Tuesday will be sufficient for a major flooding concern.

The rain is needed, however.

The U.S. Department of Agriculture’s most recent Drought Monitor, issued last Thursday, showed an area from central South Carolina up through central North Carolina as being “Abnormally Dry.” That’s the first of five levels of drought. Prior to Monday, less than a half-inch of rain had fallen this month in much of Lancaster County, and rainfall totals were only slightly higher in York and Chester counties.

Heat is not a problem, however. The increased cloudiness is preventing temperatures from soaring into the 90s, but humidity levels are very high and will remain that way through at least Wednesday, forcasters say.

This story was originally published July 23, 2018 at 3:26 PM.