Tornado Watch for parts of the Upstate, Midlands

Feb 5, 2020

Update as of 10:30 AM:

A Tornado Watch is in effect until 5 PM for the entire upstate of South Carolina and for a portion of the Midlands to the west of Columbia. The watch includes Rock Hill, Greenville, Spartanburg, and Anderson. A line of thunderstorms, with damaging wind and embedded tornadoes, is approaching from the west late this morning through mid-afternoon in these areas.

Update as of 6:15 AM:

Heavy rain is already falling over much of the Upstate and parts of the Midlands. The rain has prompted Flash Flood Warnings for Greenville county until Noon. The National Weather Service says earlier heavy rain has resulted in quickly rising stream levels throughout the Reedy and Enoree Basins. Additional stream and urban flash flooding is expected this morning. 

A line of thunderstorms is still expected to organize later this morning over the Upstate, then move rapidly eastward across the rest of the state this afternoon and evening. Here are the estimated time of arrivals, which will be refined as the storms organize:

Greenville/Spartanburg 10 AM - 1 PM
Rock Hill 1-3 PM
Columbia and Aiken 2-5 PM
Orangeburg 4-6 PM
Florence 5-7 PM
Charleston and Myrtle Beach 7-10 PM

Severe rounds of strong thunderstorms may pose a risk of multiple hazards to the Palmetto State Wednesday night and Thursday.

Scattered showers over the Midlands and Upstate Wednesday afternoon were the first signs of the approaching weather system. NOAA’s Storm Prediction Center issued an “enhanced risk” of severe storms (a level 3 risk out of a possible 5) for Thursday, primarily west of I-95 and east of I-85. A “slight risk” (level 2) was in effect for the rest of the state. The greatest potential of numerous damaging wind reports and isolated tornadoes are in the enhanced risk area. Pockets of damaging wind and isolated tornadoes are also possible in the slight risk zone.

Forecast rainfall for the 48-hour period ending midday Friday.

Occasional rain and storms Wednesday night may also pose another major concern: flash flooding. The National Weather Service posted Flash Flood Watches from Columbia westward through the Upstate, where 2 to 4 inches of rain are expected through Thursday evening. The agency said localized higher amounts are possible across the escarpment of South Carolina.

Forecast models suggested the inclement weather would arrive in several bursts. The first would arrive between midnight and daybreak, particularly over the Midlands and Upstate, as warm and humid air streams northward from the Gulf of Mexico. Heavy rain is the primary concern with the first wave; however, enough unstable air and wind shear could cause brief tornadoes or straight-line winds shortly after daybreak.

A separate, squall line of thunderstorms is expected to form around midday along a cold front, before sweeping through the Palmetto State Thursday afternoon and evening. The line is more likely to contain damaging straight-line winds, but isolated tornadoes may also spin up within the line. Here are the estimated times of arrival of the line:

Greenville/Spartanburg 10 AM - 1 PM
Rock Hill 1-3 PM
Columbia and Aiken 2-5 PM
Orangeburg 4-6 PM
Florence 5-7 PM
Charleston and Myrtle Beach 7-10 PM

Even after the leading edge of the line moves through, additional rain is likely to fall Thursday night before completely ending around daybreak Friday. A brief shot of cooler weather is forecast on Friday before temperatures return to normal over the weekend.

Meteorologists at the South Carolina Emergency Information Network strongly encourage those in the path of these storms to have multiple ways to receive weather alerts on Thursday, should quick protective action be required.