A house is surrounded by floodwaters from Hurricane Florence in Lumberton, N.C., Monday, 17 September 2018. Photo: Gerald Herbert / AP Photo

By Bob Henson 
17 September 2018
(Weather Underground) – Almost three weeks since it was first classified by the National Hurricane Center, Tropical Depression Florence is spreading heavy rain and flood risk toward the Northeast U.S., and its aftermath is still plaguing the Carolinas. Florence, which is being tracked by the NOAA/NWS Weather Prediction Center (WPC), was centered on Monday morning near the Ohio/Kentucky/West Virginia intersection, heading northeast at 15 mph. Winds are no longer a major problem with Florence, as top sustained winds are just 25 mph, but rains are still a big concern, mainly well to the northeast and east of Florence’s center.Widespread 2” – 4” rains, with pockets up to 6”, will envelop much of the interior mid-Atlantic on Monday and southern New England on Tuesday. WPC has a moderate risk of flash-flood-producing rains for Monday along a swath from northwest Virginia to south-central New York, with a slight-risk area encompassing most of the interior mid-Atlantic. The main threat north of the Carolinas is for flash flooding, although moderate river flooding was already occurring along the South River at Waynesboro and is expected by Wednesday along the Potomac at Edwards Ferry.

River flood woes will extend all week in the Carolinas

Before they can even start on recovering from Florence, folks in the hardest-hit parts of southern North Carolina and adjacent South Carolina have days of river flooding to contend with. All road transport to the region’s largest city, Wilmington, was cut off by floodwaters on Sunday, which prompted officials to explore whether supplies might need to be airlifted to the city’s 120,000 residents. Road access to Wilmington was reopened on Monday, though it may again be lost by Tuesday as river flooding begins to peak, according to the state transportation director and Governor Roy Cooper.At least five record river crests had already been established by Monday afternoon, all of them topping records established during either Hurricane Floyd (1999) or Hurricane Matthew (2016). Most of these are predicted to remain above the previous record levels throughout this week. Records set as of early Monday afternoon include:

Time series for Wilmington, NC accumulated precipitation, 17 September 2018. Data has a 1-2 day lag here. Over 80” so far, has surpassed previous record. Graphic: Jared Rennie

Other rivers expecting record or near-record flooding this week include the Cape Fear River at Fayetteville, NC; the Neuse River at Kinston, NC; the Waccamaw River near Conway, SC; and the Pee Dee River at Cheraw, SC.At least 20 deaths have been attributed to Florence, including 14 in North Carolina and six in South Carolina. See the weather.com roundup for more on Florence’s impacts.

Tallying the titanic totals from Florence’s rains

The largest reliably observed storm total from Florence as of Monday morning was 34.00” from a CoCoRaHS observer just north of Swansboro, NC. Another CoCoRaHS observer near Elizabethtown reported 35.93”, but NOAA was still in the process of confirming that total on Monday afternoon. Either way, the old record for tropical cyclone rainfall in North Carolina has been definitively smashed. Likewise, a new preliminary state record for tropical cyclone rain in South Carolina has been set with a CoCoRaHS report of 23.63” in Loris, SC. [more]

Carolinas Struggle After Florence’s 1-in-1000-Year Rains