Monday, June 1, signaled the official start of the 2020 Hurricane Season. However, two named storms (Arthur and Bertha) formed during May, and a tropical disturbance in the Bay of Campeche developed into the third tropical system of the year later in the week. To start the week, a high pressure centered over the Ohio River Valley continued to provide dry conditions and below average temperatures across the Palmetto State. The morning low temperatures rose from the low 60s into the low 80s, making for a pleasant day across the region. By Tuesday, the high pressure shifted offshore and both minimum and maximum temperatures returned to normal, but the dry weather persisted. With a few days without rain, rivers and streams were able to fall below moderate flood stage. Hurricane Hunters found data to support upgrading the tropical disturbance in the Gulf to Tropical Storm Cristobal, making it the first time on record that three name storms occurred so early in the season.
A weak low-pressure system moved through the region on Wednesday, increasing the clouds and moisture in the region, but the rain held off for one more day. Temperatures continued to climb, topping out in the upper 80s and low 90s by the afternoon. The increased moisture across the area as the high pressure moved further offshore resulted in showers and thunderstorms on Thursday. A thunderstorm near Ridgeway in Fairfield County produced pea-sized hail (0.25 inch). Heading into the weekend, showers were more widespread on Friday and some stronger thunderstorms developed in the Midlands. Communities in Edgefield, Newberry, and Kershaw counties reported wind damage associated with the storms, and the weather station located at the Camden-Woodward Field recorded a wind gust of 41 mph. At the coast, the tidal gauge at Charleston Harbor reported a high astronomical tide of 7.18 ft mean (MLLW) on Friday evening, causing shallow coastal flooding in low-lying portions around the city.
On Saturday, June 6, Tropical Storm Cristobal moved into the Gulf of Mexico and tracked northward, eventually making landfall near the Louisiana and Mississippi border on Sunday evening. The rainfall from the tropical system stayed west of the region, though scattered showers and thunderstorms formed across the state, ahead of a weak cold front. The front slowly pushed through the state on Sunday, ushering in a shot of drier air, as temperatures remained near normal for early June; with highs in the 80s to lower 90s and lows in the 70s.
(Note: The highest and lowest official temperatures and highest precipitation totals provided below are based on observations from the National Weather Service (NWS) Cooperative Observer network and the National Weather Service's Forecast Offices.)| Weekly* | Since Jan 1 | Departure | |
|---|---|---|---|
| Anderson Airport | 0.18 | 37.26 | 18.0 |
| Greer Airport | 0.67 | 41.91 | 21.6 |
| Charlotte, NC Airport | 0.32 | 28.25 | 10.4 |
| Columbia Metro Airport | 0.15 | 27.94 | 10.5 |
| Orangeburg Airport | 0.12 | 19.29 | 0.5 |
| Augusta, GA Airport | 0.06 | 28.96 | 10.4 |
| Florence Airport | 0.07 | 27.96 | 11.5 |
| North Myrtle Beach Airport | 0.13 | 21.54 | 3.1 |
| Charleston Air Force Base | 0.20 | 22.30 | 4.9 |
| Savannah, GA Airport | 0.01 | 23.05 | 5.6 |
| *Weekly precipitation totals ending midnight Sunday. M - denotes total with missing values. |
4-inch depth soil temperature: Clinton: 78 degrees. Columbia: 77 degrees. Barnwell: 71 degrees. Mullins: 75 degrees.
After Tropical Storm Bertha brought additional rainfall across the Catawba and Yadkin-Pee Dee basins last week, the rain was limited and sporadic across the state during the period. Rainfall totals since the morning of June 1 ranged from 0.10” at many locations to just shy of an inch in isolated parts of the state. The 30-day departures from normal shows wet conditions across much of the region, with areas of the state recording more than eight inches above normal.
Several rivers reached minor to moderate flood stage due to the rainfall across South Carolina and within the headwaters in North Carolina during the last part of May. The USGS streamflow data from the gauges above the Fall Line show the values were much above normal to high values at 14- and 28-day average streamflow compared to historical data.
