SCEIN

Strong thunderstorms capable of producing damaging straight line winds are possible Sunday and Monday across portions of the Palmetto State.

Forecast models suggest that isolated severe thunderstorm cells, mainly capable of damaging wind gusts, will be most likely to develop toward the northern Midlands and Upstate, where mid level energy is expected to be strongest.

Update June 3, 2020 10:00AM EDT: Tropical Storm Cristobal made landfall at approximately 9:35AM EDT Wednesday morning in the state of Campeche, Mexico with wind speeds of 60 mph.

The third tropical system of the year formed Monday, which was ironically the first day of an already busy 2020 Atlantic Hurricane Season.

The National Hurricane Center began issuing advisories on Tropical Depression Three late Monday afternoon. Radar and satellite imagery were used to identify the center of circulation near the west coast of the Yucatan Peninsula, where pockets of showers and thunderstorms were rotating around it across much of Central America and southeast sections of Mexico.

Tuesday 2pm EDT Update: Bertha has weakened to a Tropical Depression with maximum sustained wind speeds of 35 mph.

As of 2PM EDT Wednesday afternoon Bertha was located about 70 miles north-northwest of Charleston and continues to move inland at about 15 mph, delivering heavy showers to the Midlands, Pee Dee and Lowcountry regions.

Areas of strong, damaging winds and large hail are possible as a cluster of thunderstorms moves across portions of the Palmetto state Friday afternoon and early evening. For this reason, the Storm Prediction Center has issued a Severe Thunderstorm Watch until 8 PM for the Upstate and Midlands, including Columbia, Greenville, Spartanburg, and Rock Hill.

The National Oceanic and Atmospheric Administration (NOAA) anticipates an above-normal hurricane season this year for the Atlantic Ocean, Caribbean Sea and Gulf of Mexico.

Acting NOAA Administrator Neil Jacobs announced the forecast Wednesday.

The NOAA outlook predicts a 60% chance of an above-normal season, a 30% chance of a near-normal season, and only a 10% chance of a below-normal season.

Persistent heavy rainfall this week, which has led to 3 to 7 inches of rain as of Wednesday morning based on radar data and cooperative observers over the Upstate and Midlands, is likely to lead to river flooding in the coming days statewide.

Update Tuesday May 19, 2020: Round after round of showers and thunderstorms will increase the flooding threat across the Upstate and northern Midlands through Thursday.
 

Showers and thunderstorms have already produced 2 to 4 inches of rain since Monday morning for parts of the Upstate. Rain accumulations are setting the stage for flooding to develop through at least midweek.

Saturday 11 pm EDT Update: Hurricane hunters have found the tropical depression east of #Florida has strengthened into Tropical Storm #Arthur. Forecast track shifted slightly east, farther off the coast of the Carolinas.

Original story Saturday afternoon: The first tropical depression of the year has formed just east of Florida, sixteen days prior to the official start of the Atlantic hurricane season.

WEDNESDAY MIDDAY UPDATE: There is now a “high” chance of subtropical development near or north of the Bahamas this weekend, according to the 8 am outlook from the National Hurricane Center. Forecasters place the probability that a depression or storm will form at 70 percent, which is an increase from 50 percent on Tuesday.

Patches of frost are becoming increasingly likely over northern South Carolina this weekend.

A strong cold front that is expected to bring showers to much of the state Friday into Friday evening will have chilly air behind it. The air temperature on Saturday is forecast to barely push past 60 degrees in parts of the state — about 15 degrees below early May averages.

UPDATE 4:00 PM EDT: A Severe Thunderstorm Watch has been issued for the Upstate region and northern parts of the Midlands and Pee Dee, valid until 11:00 PM EDT Tuesday.

Strong to severe thunderstorms are likely to develop from west to east during the evening, beginning in the Upstate areas. A few thunderstorms have the potential to produce large hail, damaging winds, and isolated tornadoes.

Here are the most likely times of arrival for showers or thunderstorms for select locations across the state:

5 - 7 PM EDT: Western Upstate, including Greenville, Seneca and Spartanburg.

6-8 PM EDT: Rock Hill, York and Lancaster.

8 - 10 PM EDT: Bennettsville, Florence and Chesterfield. 

Update as of Noon Wednesday:

UPDATE as of Noon EDT Thursday:

The Enhanced Risk has lessened across the Palmetto State for Thursday with most of the heavy activity expected to be in the southeast part of the state.

A Slight Risk (risk level 2 out of 5) is in place for eastern parts of the Midlands and out towards the Atlantic coast of South Carolina.

On Thursday morning a powerful low pressure system was moving through the central Gulf Coast states producing strong to severe thunderstorms. This low pressure will continue to move eastward Thursday and into the overnight Friday.

Strong, damaging winds, tornadoes, and hail are possible for the third time in as many weeks on Thursday in the Palmetto State. NOAA's Storm Prediction Center issued an "enhanced risk" (a level 3 out of 5) for the Lowcountry and Central Savannah River areas of the state, including Aiken, Charleston, Hilton Head, and Walterboro. The remainder of the state is in an "slight risk" (level 2 out of 5).