Deep tropical moisture placed between low pressure to the west and high pressure to the east fueled thunderstorms across southeast Georgia.
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 CHS wrote it up.
Deep tropical moisture placed between low pressure to the west and high pressure to the east fueled thunderstorms across southeast Georgia.
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 Charleston, SC wrote its last area forecast discussion before the first event at Aug 17, 12:52 PM EST, 53 minutes earlier.
Area Forecast Discussion National Weather Service Charleston SC 152 PM EDT Tue Aug 17 2021 .SYNOPSIS... Deep tropical moisture will persist through mid week as Tropical Cyclone Fred and its remnants pass to the west and Atlantic high pressure remains to the east. Weak troughing should then persist across the region later this week through early next week. && .NEAR TERM /THROUGH TONIGHT/... Morning surface analysis/satellite imagery/regional radar data reveals Tropical Depression Fred circulation over the far western Georgia border as of 14Z. Semblance of a tropical feeder band continues to swing northward along the South Carolina coast generally north of Fripp Island with a few distinct areas of heavy rainfall sliding up through the region. Aside from relatively brief heavy rainfall, convection has largely been behaving itself. Further west, distinct dry slot noted in satellite imagery down through the far southern South Carolina counties into SE Georgia bringing some sunshine/heating to those areas. Initial band of showers/storms is expected to lift through the northern counties of the CWA through early-mid afternoon bringing a bit of a break in cloud cover/precip coverage. However, one or more additional band of showers/storms is likely to develop to our west and swing eastward...impacting areas largely west of the I-95 corridor. With heating through that area, forecast MLCAPE values in excess of 2000 J/Kg are possible by early afternoon. And, with stronger low level flow associated with TC Fred, might get a bit interesting with any storms that develop this afternoon. Our western counties remain within a marginal risk for severe per SPC Day One outlook. That said, stronger low level flow/higher effective bulk shear/helicity values will be migrating north/northeastward in time as Fred continues to migrate north. Will see how it goes... Previous discussion... Just after sunrise: The anticipated band of heavy rain has arrived and continues to spread onshore. Fortunately, the heaviest rainfall and the heaviest band has remained either just offshore or has missed the Charleston peninsula. This is great news for avoiding flooding this morning. The threat still exists through roughly mid morning. Previous discussion continues below. This morning through today: The center of Fred continues to track northward near the Alabama/Georgia state line while showers and a few thunderstorms stream onshore into the forecast area within the broader flow around Fred. Through sunrise and into mid morning, the expectation is that we will see the coverage and intensity of rainfall increase significantly, especially across southeast South Carolina. Precipitable water values will surge to around 2.3 inches, with strong moisture transport noted at 850 mb and 925 mb, in addition to upper level divergence around 300 mb. All of these factors match the numerous model signals we see for an area of heavy rainfall across southeast South Carolina, especially the Charleston Tri- County region. In this area, the heaviest rain will fall over the next 6-8 hours and the forecast is for additional rainfall amounts in the 1-2 inch range with locally higher amounts. The good news is that the mean 1000-500 mb layer flow is on the order of 20- 25 knots, so these showers and thunderstorms will be quite progressive. Therefore, the flooding threat will mostly be tied to training and repetitive rounds of heavy rainfall as opposed to storms that sit stationary or back build. Given this limitation, we think the threat of widespread flash flooding is still too low to warrant issuing a Flash Flood Watch. But, given the anticipated intense rainfall and wet antecedent conditions, at least minor flooding can be expected with at least some low end threat of an isolated flash flood event. As these bands of heavy rain impact much of southeast South Carolina through mid to late morning, we should see enough of a dry slot back to the west to produce very little convective activity for southeast Georgia. However, by the mid to late afternoon, models are consistently showing a signal for another band to develop and move across southeast Georgia and across the Savannah River into the South Carolina counties. To account for this, rain chances shift from being 80-100 percent in the Tri- County region to being 80-100 percent back to the west within this band. Heavy rain will accompany this band, but storm motion should be enough to preclude a significant flooding threat. Through the day, we will deal with a non-zero severe threat thanks to decent background wind fields and passing convection. Also, gradient winds outside of any convective activity will support frequent gusts into the 20-25 mph range especially along the coast. Highs are currently pegged for the mid to upper 80s, but could trend higher if any breaks of sun can occur. Tonight: Models show convective bands dissipating in the evening and leaving us with a window of time where there shouldn't be too much activity other than scattered showers and thunderstorms. However, later in the evening another consolidated band is expected to develop again across Colleton County and the Tri-County region. The good news is that this activity shouldn't produce quite as much heavy rain as the morning activity, but we could still see significant rainfall amounts along the South Carolina coastal region from Beaufort County up through Charleston County. Rainfall amounts of 0.5-1" will be likely with some locally higher amounts possible. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY/... Forecast confidence: Moderate. Wed: The remnants of tropical cyclone Fred will be moving north through the Appalachians while tropical cyclone Henri southwest of Bermuda remains well offshore. Abundant tropical moisture will linger over the area keeping rain chances higher than normal, although the risk for excessive rainfall should be lower given less forcing overall. Highs will be a bit warmer closer to normal with lows above normal. Thu/Fri: Inland troughing, the sea breeze and sufficient moisture should be enough to produce scattered to numerous mainly afternoon/evening showers and storms with the greatest coverage likely farther inland. Temperatures should be above normal. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Forecast confidence: Moderate. Low-level troughing should persist inland through the period with conditions generally pretty typical for this time of year. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... Small cluster of thunderstorms will impact the JZI/CHS terminal sites through 20Z or so with periodic flight restrictions most likely at CHS. Thunderstorms are expected to diminish at those sites later in the afternoon into tonight with VFR conditions returning. However, another round of showers is looking to develop along the coast and again impact the CHS/JZI terminal sites during the overnight/early morning timeframe. Additional flight restrictions are possible during that time, although I have not included any explicitly in the terminal forecasts at this juncture. Meanwhile, line of showers and thunderstorms will swing into/impact the SAV area roughly between 19Z and 23Z, with some flight restrictions possible there. Showers/storms diminish heading into the evening with VFR weather anticipated thereafter. Otherwise, gusty southeasterly winds will impact the terminal sites this afternoon into early evening. Winds weaken and veer more southerly tonight into Wednesday. Extended Aviation Outlook: Moderate to high confidence in periodic restrictions through the weekend, mostly from afternoon/evening showers and thunderstorms. && .MARINE... Today through tonight: The local waters will remain within the broader circulation around Fred and its remnants through most of the period. At solid 15-20 knots can be expected across all waters, including Charleston Harbor, today through the late evening hours. We could see occasional gusts to 25 knots, but current thinking is that winds will remain right below this threshold. The biggest candidate for frequent gusts to 25 knots will be Charleston Harbor. For now, will hold at 15-20 knots and not issue a Small Craft Advisory. The ongoing advisory for the outer Georgia waters will continue into the afternoon to account for seas to 6 feet. Otherwise, expect seas 3-5 feet. Winds and seas will start to come down late tonight as the gradient relaxes and Fred gets further away from the region. Also of note, bands of thunderstorms will move across the waters early this morning and at times through the day. These thunderstorms will be capable of producing wind gusts of 35-40 knots, and possibly even a waterspout. Wednesday through Sunday: Moderate to high confidence this period. Tropical cyclone Henri well offshore will make a clockwise loop near Bermuda through late week with little impact on the local waters. Atlantic high pressure will then return along with an inland trough. This pattern will maintain slightly elevated winds (mainly from the south/southwest) with seas 4 feet or less. Rip Currents: Strengthening onshore flow, astronomical influences from the upcoming perigee, and the presence of some swell energy will combine to produce a moderate risk of rip currents at all beaches today. Also, a moderate risk will be possible through mid week depending on the amount of lingering swell energy impacting the beaches. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...Small Craft Advisory until 4 PM EDT this afternoon for AMZ374. && NEAR TERM...BSH/TBA SHORT TERM...RJB LONG TERM...RJB AVIATION...RJB/TBA MARINE...BSH/RJB
Hazardous Weather Outlook National Weather Service Charleston SC 1135 AM EDT Tue Aug 17 2021 SCZ049-050-181545- Coastal Colleton-Charleston- 1135 AM EDT Tue Aug 17 2021 ...MODERATE RISK FOR RIP CURRENTS IN EFFECT UNTIL 8 PM EDT THIS EVENING... This Hazardous Weather Outlook is for southeast South Carolina. .DAY ONE...This afternoon and tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Moderate Risk for Rip Currents. Heavy Rainfall: A few clusters of heavy rainfall producing thunderstorms will continue to move across portions of southeast South Carolina through early afternoon. The intense rainfall rates may produce at least minor flooding in and around urban areas including, but not limited to, Summerville, Charleston, and Moncks Corner. While most impacts will likely be minor, flash flooding could also occur if the heaviest rain repeatedly impacts the same area. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter assistance is not anticipated at this time. SCZ043>045-052-181545- Inland Colleton-Dorchester-Inland Berkeley-Tidal Berkeley- 1135 AM EDT Tue Aug 17 2021 This Hazardous Weather Outlook is for southeast South Carolina. .DAY ONE...This afternoon and tonight. Heavy Rainfall: A few clusters of heavy rainfall producing thunderstorms will continue to move across portions of southeast South Carolina through early afternoon. The intense rainfall rates may produce at least minor flooding in and around urban areas including, but not limited to, Summerville, Charleston, and Moncks Corner. While most impacts will likely be minor, flash flooding could also occur if the heaviest rain repeatedly impacts the same area. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter assistance is not anticipated at this time. AMZ330-350-352-354-374-GAZ087-088-099>101-114>116-118-137-138-140- SCZ040-042-047-181545- Charleston Harbor- Waters from South Santee River to Edisto Beach SC out 20 NM- Waters from Edisto Beach SC to Savannah GA out 20 NM- Waters from Savannah GA to Altamaha Sound GA out 20 NM, including Grays Reef National Marine Sanctuary- Waters from Savannah GA to Altamaha Sound GA from 20 to 60 NM- Jenkins-Screven-Candler-Bulloch-Effingham-Tattnall-Evans- Inland Bryan-Inland Chatham-Long-Inland Liberty-Inland McIntosh- Allendale-Hampton-Inland Jasper- 1135 AM EDT Tue Aug 17 2021 This Hazardous Weather Outlook is for Atlantic coastal waters, southeast Georgia and southeast South Carolina. .DAY ONE...This afternoon and tonight. The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter assistance is not anticipated at this time. GAZ117-119-139-141-SCZ048-051-181545- Coastal Bryan-Coastal Chatham-Coastal Liberty-Coastal McIntosh- Beaufort-Coastal Jasper- 1135 AM EDT Tue Aug 17 2021 ...MODERATE RISK FOR RIP CURRENTS IN EFFECT UNTIL 8 PM EDT THIS EVENING... This Hazardous Weather Outlook is for southeast Georgia and southeast South Carolina. .DAY ONE...This afternoon and tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Moderate Risk for Rip Currents. Severe Thunderstorms: Additional thunderstorms are possible this afternoon into early evening. A few storms might produce damaging wind gusts. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter assistance is not anticipated at this time.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHARLESTON SC
1019 AM EDT TUE AUG 17 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1006 AM HEAVY RAIN 1 WNW CHARLESTON 32.79N 79.95W
08/17/2021 U0.00 INCH CHARLESTON SC PUBLIC
THE PUBLIC REPORTED THE INTERSECTION OF PRESIDENT
STREET AND LINE STREET CLOSED FROM RECENT RAINS.
&&
EVENT NUMBER CHS2100566
DPBSpecial Weather Statement
National Weather Service Charleston SC
1258 PM EDT Tue Aug 17 2021
SCZ050-171730-
Charleston-
1258 PM EDT Tue Aug 17 2021
...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF CHARLESTON COUNTY...
At 1258 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm over Bears Bluff, or 9 miles west of Johns
Island, moving northeast at 15 mph.
HAZARD...strong winds 45 to 55 mph.
SOURCE...Radar Indicated.
IMPACT...Expect minor damage to tree limbs and blowing around of
light, unsecured objects.
Some locations in the path of this storm include...
West Ashley, Johns Island, Hollywood, Ravenel, Meggett, Yonges
Island, Bears Bluff and Wadmalaw Island.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Torrential rainfall is also occurring with this storm and may lead to
flooding of low lying and poor drainage areas. Do not drive your
vehicle through flooded roadways.
This storm may intensify. Be certain to monitor local radio and TV
stations as well as local cable TV outlets for additional information
and possible warnings from the National Weather Service.
&&
LAT...LON 3259 8022 3262 8030 3283 8027 3279 8007
TIME...MOT...LOC 1658Z 203DEG 14KT 3265 8023
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPH
SPRSpecial Weather Statement
National Weather Service Charleston SC
230 PM EDT Tue Aug 17 2021
GAZ116>119-138-139-171900-
Coastal Liberty-Coastal Chatham-Inland Liberty-Inland Chatham-Inland
Bryan-Coastal Bryan-
230 PM EDT Tue Aug 17 2021
...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF BRYAN, LIBERTY,
MCINTOSH AND CHATHAM COUNTIES...
At 230 PM EDT, National Weather Service doppler radar indicated
strong thunderstorms along a line extending from near Bloomingdale to
near Retreat, and moving northeast at 20 mph.
HAZARD...strong winds 45 to 55 mph and excessive cloud to ground
lightning.
SOURCE...Radar Indicated.
IMPACT...Expect minor damage to tree limbs and blowing around of
light, unsecured objects. All outdoor activities should
cease. Move indoors immediately.
Some locations in the path of these storms include...
Pooler, Richmond Hill, Coffee Bluff, Savannah International Airport,
I-16/I-95 Interchange, Hunter Army Airfield, Godley Station and
Downtown Savannah.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Report damage directly to the Charleston National Weather Service at
888-383-2024 when it is safe to do so. You can also email your
report to nws.charlestonsc@noaa.gov.
&&
LAT...LON 3211 8138 3224 8119 3223 8115 3220 8112
3216 8113 3215 8112 3214 8112 3173 8108
3170 8110 3165 8126 3166 8132 3165 8134
3165 8141
TIME...MOT...LOC 1830Z 236DEG 18KT 3207 8134 3169 8137
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPH
ETMThe Charleston,SC radar (KCLX), 57 km away, was scanning. The volume nearest the first event began at 18:45 UTC.
1 lightning. Local standard time, as filed.
A Chatham County emergency manager reported a lightning strike setting fire to two homes under construction along Shoefstall Street.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Georgia in 2021Every state in 2021This day in weather historyWarnings in Georgia, 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: 979066.