Scattered to numerous showers and thunderstorms developed along a pre-frontal trough in a very hot and unstable environment over the North Carolina Piedmont. Weak steering flow combined with the unstable environment resulted in both slow moving showers and thunderstorms and strong downdrafts, with new thunderstorms developing along the subsequent outflow boundaries.
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.
Scattered to numerous showers and thunderstorms developed along a pre-frontal trough in a very hot and unstable environment over the North Carolina Piedmont. Weak steering flow combined with the unstable environment resulted in both slow moving showers and thunderstorms and strong downdrafts, with new thunderstorms developing along the subsequent outflow boundaries. The storms produced damaging winds and isolated large hail and flash flooding.
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 Aug 14, 1:30 PM EST, 5 minutes earlier.
AREA FORECAST DISCUSSION National Weather Service Raleigh NC 230 PM EDT Sat Aug 14 2021 .SYNOPSIS... On the western periphery of a strong, subtropical ridge centered off the coast Carolinas, a cold front will approach slowly from the northwest this afternoon and will eventually merge with a surface trough as it settles over central NC tonight through Sunday. && .NEAR TERM /THROUGH TONIGHT/... As of 10 AM Saturday... ...The Heat Advisory Has Been Expanded... Upon reviewing the 12z morning COOP data, at least 2 stations in and near Granville and Vance counties reached 98 degrees(Kerr Lake and Philpot) yesterday. Additionally, there were numerous locations along the US 1 corridor that reported heat indices between 105-110 degrees. As such, have elected to expand the Heat Advisory to now include the Granville, Vance Counties, Chatham, Lee and then the remainder of the NC Sandhills(Moore, Scotland, and Hoke). Either way, central NC will see one last day of sweltering conditions before temperatures cool on Sunday. Highs today ranging from lower 90 NW to mid 90s elsewhere, with some upper 90s possible in the typically hotter/urban areas. When combined with the muggy dewpoints in the lower to mid/upper 70s, heat indices along and east of the Triangle will range between 105 to 110. West of the Triangle, while still hot, heat indices will remain between 100 to 103, remaining below advisory criteria. Convection will initially fire along the pre-frontal trough located across the NC Foothills and far western Piedmont counties between 18 to 21z. These storms will generally move east-northeastward with subsequent storm development along related outflow. Then between 21 to 03z, the approach and then consolidation of the cold front with the pre-frontal trough and any ongoing convection will likely result in an uptick in coverage, mainly across the northern Piedmont and northern coastal plain, where the surface front is forecast to settle over the area. Convective coverage today will be more isolated in nature farther south across the Sandhills and southern Coastal Plain, but still can't be ruled out. Though deep shear remains weak, MLCAPE maximized into the 2000-3000 J/kg combined with very high DCAPE values of 1000-2000 J/KG, will support locally strong to marginally severe gusts capable of damage. While, the greatest heavy rain threat is expected to remain to the north in VA, cannot rule out some urban flooding across the far northern Piedmont counties, including the Triad. Overnight: Convection is forecast to gradually wane overnight as sfc CIN develops in the rain/outflow cooled air along the front. Lows 70 to 75 with areas of stratus and/or fog INVOF the front. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... As of 400 AM Saturday... As Fred moves north through the eastern Gulf of Mexico on Sunday, tropical moisture ahead of it converging with a stationary front over central NC will provide a setup for widespread showers and storms across the area. POPs range from categorical in the northern and western Piedmont to likely elsewhere. While the severe threat looks a bit lower than today with cooler temperatures and less instability to work with, a few strong to severe storms with locally damaging winds still cannot be ruled out. PW values in excess of 2 inches across the area mean localized heavy rain and flash flooding are also possible. WPC QPF on Sunday and Sunday night is currently around a half inch to an inch, highest NW closest to the stalled front, but locally higher amounts are possible, and the entire region is in a marginal risk for excessive rainfall. The good news is the front and widespread clouds/precipitation will finally give us some relief from the hot temperatures, with highs ranging from the lower-80s north to upper-80s south, though it will still be humid with dew points in the 70s. Lows Sunday night will be in the upper-60s to lower-70s. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 345 AM Saturday... A stationary front will weaken and linger across the area into early next week, before dissipating. Meanwhile, the remnants of TC Fred are expected to lift northward and into the Deep South by early next week, then weakening substantially and lifting northward into the TN Valley. However, moisture will still stream northward and into area area (PW's of around 2 inches), while interacting with the aforementioned weakening front over our region to produce numerous showers and storms early next week. Meanwhile, strong subtropical ridging will remained parked off the coast of the Carolinas, allowing for the best chance of showers and storms across western portions of the area. Regardless, this pattern will lead to well above normal chances for showers and storms, with a threat of flash flooding during this time. The mid/upper ridge will expand southwestward over the Deep South in the wake of the remnants of TC Fred, allowing of the deep southerly/southwesterly flow over the Carolinas to become more southwesterly to westerly mid level flow to develop by late week. However, with a continued moisture rich low level airmass should allow for at least diurnal convection each day from mid to late week. Highs temps are expected to be around 80 northwest to the mid to upper 80s southeast Monday through Wednesday, before warming back into the mid to upper 80s areawide by late week. Low temps are expected to be in the upper 60s to lower 70s. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... As of 230 PM Saturday... 24-hour TAF period: Scattered thunderstorms have already developed across the western and central terminals(KINT, KGSO and KRDU) and coverage will continue to increase through the late afternoon and linger into the evening as a weak cold front approaches from the northwest. A brief period of strong gusty winds and sub-VFR conditions will be possible with the stronger storms. At KRWI and KFAY, coverage will be more isolated in nature and will handle any impacts with near term TAF amendments. The weak cold front will settle near the NC-VA border. Moisture pooling along the front will likely result the development of IFR to MVFR ceilings between 06 to 12z at all but the KFAY TAF site, which should remain VFR. With the front stalled across the area, these sub- VFR ceilings across the northern TAF sites will be slow to lift, potentially remaining MVFR until midday/early afternoon. Scattered to numerous showers and storms are expected again Sunday afternoon, with the greatest coverage expected across the western and central terminals. -CBL Looking beyond 18z Sunday: As the front stalls near or over the area and tropical moisture from Fred gets drawn north, multiple rounds of showers and a few storms are expected each day through the rest of the period across all of central NC. Sub-VFR conditions from fog/low stratus are also possible each morning. -Danco && .RAH WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 7 PM EDT this evening for NCZ008>011-025>028- 040>043-075>078-085-086-088-089. && SYNOPSIS...MWS/Danco NEAR TERM...CBL SHORT TERM...Danco LONG TERM...BSD AVIATION...CBL/Danco
Hazardous Weather Outlook National Weather Service Raleigh NC 1013 AM EDT Sat Aug 14 2021 NCZ008>011-025>028-040>043-075>078-085-086-088-089-151415- Granville-Vance-Warren-Halifax-Durham-Franklin-Nash-Edgecombe- Chatham-Wake-Johnston-Wilson-Moore-Lee-Harnett-Wayne-Scotland-Hoke- Cumberland-Sampson- 1013 AM EDT Sat Aug 14 2021 ...HEAT ADVISORY IN EFFECT UNTIL 7 PM EDT THIS EVENING... This Hazardous Weather Outlook is for central North Carolina. .DAY ONE...Today and tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Heat Advisory. Additionally, isolated strong to damaging wind gusts, and locally heavy downpours and flooding, will be possible. .DAYS TWO THROUGH SEVEN...Sunday through Friday. Strong to damaging wind gusts, and locally heavy downpours and flooding, will be possible in scattered to locally numerous thunderstorms on Sunday. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. NCZ007-021>024-038-039-073-074-083-084-151415- Person-Forsyth-Guilford-Alamance-Orange-Davidson-Randolph-Stanly- Montgomery-Anson-Richmond- 1013 AM EDT Sat Aug 14 2021 This Hazardous Weather Outlook is for central North Carolina. .DAY ONE...Today and tonight. Strong to damaging wind gusts, and locally heavy downpours and flooding, will be possible in scattered to locally numerous thunderstorms today. .DAYS TWO THROUGH SEVEN...Sunday through Friday. Strong to damaging wind gusts, and locally heavy downpours and flooding, will be possible in scattered to locally numerous thunderstorms on Sunday. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
Special Weather Statement
National Weather Service Raleigh NC
146 PM EDT Sat Aug 14 2021
NCZ075-141830-
Moore NC-
146 PM EDT Sat Aug 14 2021
...A strong thunderstorm will impact portions of central Moore County
through 230 PM EDT...
At 142 PM EDT, Doppler radar was tracking a strong thunderstorm over
Carthage, moving slowly northeast at 5 mph. Heavy rainfall and
frequent lightning is occurring with this Storm.
HAZARD...Winds up to 30 mph, half inch hail, and heavy rainfall.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
Locations impacted include...
Carthage, Whispering Pines and Seven Lakes.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Heavy rainfall is occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
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 3536 7961 3544 7952 3547 7936 3544 7933
3543 7933 3542 7931 3536 7927 3535 7927
3534 7926 3525 7937 3522 7951
TIME...MOT...LOC 1742Z 238DEG 6KT 3533 7945
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...30 MPH
CASpecial Weather Statement
National Weather Service Raleigh NC
147 PM EDT Sat Aug 14 2021
NCZ026-041-141830-
Franklin NC-Wake NC-
147 PM EDT Sat Aug 14 2021
...A strong thunderstorm will impact portions of northeastern Wake
and south central Franklin Counties through 230 PM EDT...
At 145 PM EDT, Doppler radar was tracking a strong thunderstorm 8
miles east of Raleigh, moving east at 10 mph.
HAZARD...Winds in excess of 40 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
Locations impacted include...
Raleigh, Garner, Zebulon, Knightdale, Wendell, Rolesville and Pilot.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Heavy rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
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 3582 7825 3575 7837 3569 7863 3587 7868
3601 7831
TIME...MOT...LOC 1745Z 252DEG 10KT 3583 7851
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH
ASThe Raleigh/Durham radar (KRAX), 24 km away, was scanning. The volume nearest the first event began at 18:33 UTC.
10 thunderstorm wind, 3 hail, 1 flash flood. Local standard time, as filed.
A tree was reported down at Highway 64 West near Zebulon.
The public reported nickel size hail in north Raleigh near Falls Lake.
The public reported nickel size hail near Cary Parkway and Holly Springs Road.
A tree was reported down near the intersection of Fall Line Court and Old Creedmoor Road.
A tree was reported down near the intersection of North Falls Drive and Creedmoor Road.
A tree was reported down along Melvin Arnold Road.
A tree was reported down near the intersection of Norwood Road and Mount Vernon Church Road.
A large tree was reported down near the intersection of Avent Ferry Road and Center Hill Drive. The road was closed between Center Hill Drive and New Hill Holleman Road.
The public reported up to quarter size hail at the Raleigh Durham International Airport.
A tree was reported down across the road near the intersection of Beaver Dam Lane and Shore Road.
A tree was reported down near the intersection of Knob View Drive and Mountain View Road Northwest.
A couple of trees were reported down on Country Club Road between Queensbury Road and Ryandale Road.
A tree was reported down near the intersection of Bentley Court and Westhaven Circle.
The USGS River Observation along North Buffalo Creek at Westover Terrace rose above minor flood stage between 730 pm and 745 pm.
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, August 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: 982066, 982049, 982050, 982064, 982065, 982060, 982062, 982052, 982051, 982053, 982058, 982055, 982056, 982048.