There was a brief reprieve from the heat and humidity for the first part of the week as slightly cooler and drier air moved in behind the cold front on Monday, July 1. A large area of showers and thunderstorms developed along a cold front pushing through the state. A flood watch was issued for most of the Lowcountry; despite drought conditions in the region, high rainfall rates produced flash flooding, including in Charleston. Emergency managers and law enforcement reported over two dozen intersections and roads closed due to flooding. Total rainfall amounts between two and four inches were reported across the Lowcountry, with localized amounts over six inches, and a CoCoRaHS observer near Mount Pleasant reported 4.24 inches of rain within two hours on Monday afternoon. During the evening, the tidal gauge at the Charleston Harbor station recorded a tide of 7.11 feet MLLW, causing minor flooding along the coast. Tuesday's temperatures were between five and ten degrees cooler than normal for the beginning of July, with morning lows in the low to mid-60s and highs reaching the mid to upper 80s. Temperatures began warming on Wednesday and would persist through the rest of the period which also experienced a few scattered afternoon showers and thunderstorms.
High pressure off the coast helped increase heat and humidity over the region on Thursday, leading to high heat indices through the weekend and contributing to daily showers and thunderstorms across the state. Multiple high minimum temperatures were tied or broken over the weekend, including 80 degrees as a low on Friday morning recorded by both the NWS stations in North Myrtle Beach and the University of South Carolina in Richland County. The NWS stations at the Anderson Regional Airport and the Greenville-Spartanburg International Airport reported a high of 101 degrees on Friday afternoon, breaking the daily record of 99 degrees at both stations set in 1993 and 2012, respectively. Another day of high dewpoints and temperatures in the mid to upper 90s on Saturday and Sunday produced heat indices up to and above 110 degrees, and heat advisories were issued for much of the state. Late Sunday evening, a band of thunderstorms moved out of the Upstate and met another band moving to the east across the Midlands late Sunday evening, producing heavy rain and flash flooding in portions of Fairfield and Lancaster counties.
(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 | 2.05 | 29.22 | 4.5 |
| Greer Airport | 1.01 | 30.11 | 4.7 |
| Charlotte, NC Airport | 1.76 | 25.48 | 3.0 |
| Columbia Metro Airport | 0.86 | 24.25 | 1.4 |
| Orangeburg 2 (COOP) | 0.35 | 19.53 | -6.3 |
| Augusta, GA Airport | 3.62 | 24.09 | 0.8 |
| Florence Airport | 0.32 | 18.11 | -3.7 |
| North Myrtle Beach Airport | 0.20 | 17.19 | -3.5 | Charleston Air Force Base | 1.81 | 25.19 | 1.1 |
| Savannah, GA Airport | 2.04 | 24.37 | -0.2 |
| *Weekly precipitation totals ending midnight Sunday. M - denotes total with missing values. s - denotes total with suspect data. |
4-inch depth soil temperature: Clinton: Not Available. Columbia: 81 degrees. Barnwell: 81 degrees. Mullins: 77 degrees.
Most of the state, north, and west of the Interstate 20 corridor, recorded more than half an inch of rain, with isolated parts of the Midlands and Upstate measuring up to five inches due to the scattered nature of thunderstorms in these regions and the slow movement of storms on Sunday. Interior portions of the Lowcountry and Pee Dee regions recorded less than a quarter of an inch, with some higher rainfall totals reported along the immediate coast. Despite the rainfall during the period, the extent of the moderate drought (D1) conditions on the U.S. Drought Monitor expanded across the northern Midlands and into the Upstate as conditions worsened. Severe drought (D2) conditions were introduced into much of the Pee Dee due to the continued below-normal precipitation totals, lack of soil moisture, and below-normal streamflow across the region.
Higher rainfall totals in portions of the state slightly improved the 14-day average streamflow values at gauges in the Upstate, including those in the Upper Savannah and Upper Santee watersheds. However, the multiple periods without widespread rainfall caused the 14-day average streamflow values at gauges across the Midlands and Coastal Plain to remain below average. Many gauges within the Pee Dee Watershed recorded values well below average for this time of year. Heavy rain Sunday evening near the Little Saluda at Saluda caused the river height to rise rapidly into the moderate flood stage. Elsewhere, river height gauges across the state remained below the action stage. Tidal gauges recorded some tide levels reaching the action and minor stages during the week.
