An approaching cold front west and northwest of the Appalachian mountains tracked east into central North Carolina. A pre-frontal trough ahead of the cold front forced showers and thunderstorms during the evening hours, with several damaging wind reports and one lightning related house fire.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS RAH wrote it up.
An approaching cold front west and northwest of the Appalachian mountains tracked east into central North Carolina. A pre-frontal trough ahead of the cold front forced showers and thunderstorms during the evening hours, with several damaging wind reports and one lightning related house fire.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Raleigh, NC wrote its last area forecast discussion before the first event at Jul 17, 2:30 PM EST, 55 minutes earlier.
AREA FORECAST DISCUSSION National Weather Service Raleigh NC 330 PM EDT Sat Jul 17 2021 .SYNOPSIS... High pressure just off the Carolina coast will drift southeast and weaken through tonight, as a surface cold front and upper level trough approach from the northwest. High chances for showers and storms are expected tonight through Monday as the cold front moves slowly through the area and stalls overhead. Drier air will move in for Tuesday and Wednesday. && .NEAR TERM /THROUGH TONIGHT/... As of 252 PM Saturday... Convection started early today due in part to the high surface dewpoints and strong early-day heating, pushing MLCAPE up so far to an impressive 2000-3000 J/kg. Deep layer bulk shear remains quite low, with mid level steering flow of just 15-20 kts, which has helped limit storm maintenance somewhat thus far, although a few cells have become briefly strong and this should persist through the evening. Both lightning flash counts and lightning density have been impressive in a few cells, as suggested by N-CAPE of 0.20-0.25 and high hail CAPE around 1000 J/kg, indicating that robust updrafts will be possible despite poor mid level lapse rates (under 6 C/km). But the deep layer shear will start an upward trend through tonight as the elongated shortwave trough from the St Lawrence SSW through WV/E TN to MS/AL plods eastward into and through the Appalachians through tonight, helping to sharpen up the upper jet to our N and increasing our large scale forcing for ascent. Expect showers and storms to keep filling in over the next several hours, with activity slowly easing eastward into the NE CWA later tonight. Lingering ground heat flux along with upper-trop cooling after nightfall should help support convection lasting well into the night, with marginal CAPE lasting well past midnight E of Highway 1. Will carry good chance to likely pops (and isolated categorical in the very short term in places where storms are occurring or imminent) through the evening, slowly decreasing and shifting into S and E sections through the night. Patchy fog is possible in some sheltered places that receive rain late tonight. Lows 69-75. -GIH && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... As of 330 PM Saturday... ...Flash flood watch may be needed for Sun through Mon night... The initial mid level shortwave trough will dampen as it moves slowly eastward through the Mid Atlantic/Carolinas Sun, although a low moving through New England and energy diving into the mean long wave trough into the Ohio Valley/Mid Miss Valley/Mid South will help maintain a marginal deep layer shear supportive of sustained convection ahead of the very weak surface front approaching from the NW. With PW expected to increase to 2+" over the S and E CWA and forecast soundings suggesting warm rain processes at play and with an overall somewhat slow storm motion and favorable orientation for training, locally high rainfall totals are possible. This may necessitate the need for a flash flood watch. But a number of questions remain, including the possibility that the heavy rainfall may be isolated to small areas beneath meandering storm clusters, plus our S and E CWA has seen a rainfall deficit in the last week, implying that rivers/streams and the ground can handle a widespread 1-2" of rain that may occur Sun/Sun night. Given this, will hold off and wait for another set of model runs and more observational clarity before pulling the trigger on a watch. This notwithstanding, we should still see high coverage of showers and storms starting Sun afternoon (it could start earlier, though, as was the case today, with a lot depending on how much convective debris cloudiness there is in the morning that might delay heating), continuing through much of the night, with total amounts likely to approach or exceed one inch everywhere with pockets of higher amounts. Expect highs from the mid 80s NW to low 90s SE, followed by lows of 68-73 as the surface front drifts into our NW sections overnight. -GIH && .LONG TERM /MONDAY THROUGH SATURDAY/... As of 235 PM Saturday... Same front, different day. Frankly, the models show the front that will be over the region Monday morning making little progress throughout the entire week. The front will eventually weaken and serve as less of a forcing mechanism, but at least at the beginning of the week, there are indicators from model guidance that there could be isolated areas with extremely heavy rainfall. The 12Z NAM put out some bulls-eyes of 5 inches of rain in 24 hours, the 00Z GFS did something similar, and a 00Z run of the European model also showed the possibility for heavy rainfall as well. It is too early to pinpoint any specific locations that could receive heavy rainfall (so no flash flood watch will be issued at this time), but the threat is definitely there. This is already highlighted in the Hazardous Weather Outlook. Through the extended forecast, Monday still appears to be the day with both the greatest coverage of rain as well as the most intense rain. There will be a diminishing trend through the week, with rainfall likely across southern counties on Tuesday, then chance pops on Wednesday before at least one dry day is possible on Thursday. A slight chance of thunderstorms returns to the forecast for Friday and Saturday. With the extensive cloud cover and rainfall on Monday, that should be the coolest day of the week, with highs only in the low to mid 80s. Temperatures return to values near climatology on Wednesday and will remain that way into the weekend. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... As of 1215 PM Saturday... We've mostly seen VFR conditions thus far today, although as cloud bases are lifting with heating, some areas have gone to briefly broken skies with a couple of hours of MVFR cigs. These should continue lifting to VFR, and this should hold until mid afternoon (19z-20z). Isolated trending to scattered showers and storms will develop by this time, with coverage increasing first near INT/GSO by 20z with storms then moving E to RDU and eventually RWI/FAY this evening (22z-04z), ending last near RWI. These will generate periods of sub-VFR conditions with gusty and erratic winds in and near storms. Storm coverage will decrease overnight, and most places will see VFR cigs dominating through midday Sun, however a few hours of MVFR to IFR cigs are possible near RDU and RWI 07z-12z. Surface winds will be from the SW 8-15 kts gusting at times to 20 kts this afternoon, decreasing to under 10 kts this evening through Sun morning. Looking beyond 18z Sun, above normal shower/storm chances, producing unsettled weather with periods of sub-VFR conditions, will continue Sun and Mon, mainly (but not only) each afternoon through mid evening. A few hours of sub-VFR fog may also occur early Mon at all terminals. VFR conditions are then expected Tue through Thu as high pressure builds into the area. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... None. && SYNOPSIS...Leins/GIH NEAR TERM...Hartfield SHORT TERM...Hartfield LONG TERM...Green AVIATION...Hartfield
Hazardous Weather Outlook National Weather Service Raleigh NC 426 AM EDT Sat Jul 17 2021 NCZ007>011-021>028-038>043-073>078-083>086-088-089-181200- Person-Granville-Vance-Warren-Halifax-Forsyth-Guilford-Alamance- Orange-Durham-Franklin-Nash-Edgecombe-Davidson-Randolph-Chatham-Wake- Johnston-Wilson-Stanly-Montgomery-Moore-Lee-Harnett-Wayne-Anson- Richmond-Scotland-Hoke-Cumberland-Sampson- 426 AM EDT Sat Jul 17 2021 This Hazardous Weather Outlook is for central North Carolina. .DAY ONE...Today and tonight. Showers and storms will become more numerous across the area today. A few storms near the NC/VA border may be strong to severe. The primary threats will be periods of heavy rain and gusty winds. .DAYS TWO THROUGH SEVEN...Sunday through Friday. Numerous showers and storms are possible Sunday through Tuesday as a front stalls out across central NC. Locally heavy rainfall will lead to the risk of flooding, especially in low lying or poor drainage areas. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
Special Weather Statement
National Weather Service Raleigh NC
356 PM EDT Sat Jul 17 2021
NCZ021-022-038-172100-
Guilford NC-Forsyth NC-Davidson NC-
356 PM EDT Sat Jul 17 2021
...A STRONG THUNDERSTORM WILL AFFECT SOUTHEASTERN FORSYTH...
NORTHEASTERN DAVIDSON AND WEST CENTRAL GUILFORD COUNTIES UNTIL 500 PM
EDT...
At 354 PM EDT, Doppler radar was tracking a strong thunderstorm near
Clemmons, or near Winston-Salem, moving northeast at 25 mph.
Pea size hail and wind gusts up to 40 mph will be possible with this
storm. Deadly cloud to ground lightning is occurring with this storm.
Locations impacted include...
Greensboro, Winston-Salem, High Point, Kernersville, Clemmons,
Stokesdale, Walkertown, Belews Creek, Arcadia and Sedge Garden.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Seek shelter in a nearby building or vehicle. Wind gusts as high as
40 mph are capable of knocking down tree limbs and blowing around
light outdoor objects.
This thunderstorm has the potential for an excessive amount of
deadly cloud to ground lightning. Seek shelter indoors and stay away
from windows. If you cannot seek shelter indoors, an enclosed
vehicle can provide safe shelter. Deadly lightning strikes can occur
well ahead of an approaching storm, prior to the arrival of rain and
wind.
&&
LAT...LON 3604 8044 3626 8008 3626 8005 3606 7989
3589 8031
TIME...MOT...LOC 1954Z 238DEG 22KT 3601 8031
GIHSpecial Weather Statement National Weather Service Raleigh NC 424 PM EDT Sat Jul 17 2021 NCZ039-040-074-075-172100- Chatham NC-Randolph NC-Montgomery NC-Moore NC- 424 PM EDT Sat Jul 17 2021 ...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN MOORE... NORTHEASTERN MONTGOMERY...SOUTHEASTERN RANDOLPH AND SOUTHWESTERN CHATHAM COUNTIES UNTIL 500 PM EDT... At 423 PM EDT, Doppler radar was tracking a strong thunderstorm near North Carolina Zoo, moving northeast at 25 mph. Wind gusts up to 35 mph will be possible with this storm. Locations impacted include... North Carolina Zoo, Seagrove, Harpers Crossroads, Highfalls, Coleridge and Steeds. PRECAUTIONARY/PREPAREDNESS ACTIONS... Frequent cloud to ground lightning is occurring with this storm. Lightning can strike 10 miles away from a thunderstorm. Seek a safe shelter inside a building or vehicle. && LAT...LON 3540 7986 3563 7983 3577 7954 3549 7945 TIME...MOT...LOC 2023Z 243DEG 22KT 3559 7970 Kren
The Raleigh/Durham radar (KRAX), 11 km away, was scanning. The volume nearest the first event began at 20:27 UTC.
21 thunderstorm wind, 1 lightning. Local standard time, as filed.
An emergency manager reported a house was struck by lightning, causing a structure fire.
A tree fell down and knocked down power lines near the intersection of Rosecrest Dr and Hawthorne St in Greensboro.
A tree was reported down near the intersection of East Cone Blvd and Yanceyville St.
A tree was reported down near the intersection of Rankin Rd and Summit Ave.
A tree was reported down near the intersection of Friendly Ave and Hobbs Rd.
A tree was reported down near the intersection of Bason Rd and Pine Lake Ln.
One tree fell down near the intersection of Hassel St and Tryon St.
One tree fell down near the intersection of Burlington Rd and Snipes Rd.
One tree fell down near the intersection of North Carolina Highway 57 and Guess Rd.
Power lines were down across the roadway at the intersection of Terry Rd and St. Mary's Rd.
A tree fell down near the intersection of Ned Moore Rd and Windy Creek Cir.
A tree fell down near the intersection of Dick Holeman Rd and Forest View Dr.
One tree fell on power lines on Surl Mount Tirzah Rd.
One tree fell down near the intersection of Olivet Church Rd and Birchdale Dr.
Multiple trees were reported down near the 8900 block of Red Bank Rd.
Multiple trees were reported down near the 6000 block of Sullivan Town Rd.
Multiple trees fell down near the intersection of Tuttle Ridge Rd and Baux Mountain Rd.
Trees were uprooted and snapped in the town of Oak Ridge.
A tree fell down near the intersection of North Carolina Highway 68 and Oak Ridge Rd.
One tree fell down across the road at the intersection of North Carolina Highway 68 and Case Ridge Dr.
Law enforcement reported multiple trees down near the intersection of Dick Holeman Rd and Durham Rd.
Roxboro fire department reported trees fell on power lines and on a car near the intersection of Clay Long Rd and Hurdle Mills Rd.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in North Carolina in 2021Every state in 2021This day in weather historyWarnings in North Carolina, July 2021
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 970853, 970854, 970855, 970856, 970857, 970858, 970859, 970860, 970861, 970862, 970863, 970864, 970865, 970866, 970868, 970869, 970870, 970871, 970872, 970873, 970874, 970875.