Isolated thunderstorms developed in the early afternoon hours on the sea breeze along the southeast Georgia coast. One thunderstorm produced frequent lightning, striking a building in Savannah.
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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.
Isolated thunderstorms developed in the early afternoon hours on the sea breeze along the southeast Georgia coast. One thunderstorm produced frequent lightning, striking a building in Savannah.
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 Jul 17, 10:54 AM EST, 2 hours 51 minutes earlier.
Area Forecast Discussion National Weather Service Charleston SC 1154 AM EDT Mon Jul 17 2023 .SYNOPSIS... A surface trough will persist inland today, while Atlantic high pressure holds offshore through the week. A cold front could impact the region this weekend. && .NEAR TERM /THROUGH TONIGHT/... The forecast is largely on track. Some slight adjustments were made to hourly pops to account for better timing per latest high res data. Still looks as though the Charleston Tri-County is the favored area for convection by mid-late afternoon, although a cluster may make a run for Savannah Metro late afternoon/early evening. Dewpoints were also adjusted slightly, which brought max heat index values up a bit along the coast. Values are still below Heat Advisory criteria, although it would not be surprising to see a few spots hit 110 before the onset of convection or cooling from the passage of the sea breeze. Today: 17/12z surface analysis showed a weak cold front/surface trough extending across parts of central Georgia then snaking back through the southern South Carolina Midlands.and up into parts of the Pee Dee. The front is on target to sink into parts of interior Southeast Georgia over the next few hours as a weak frontal wave develops near Allendale, SC. As the weak wave develops, it will tend to help keep a tongue of low-level moisture in place across parts of the Charleston Tri-County into Colleton County as dewpoints pool back along the entire coast with the afternoon sea breeze. This will essentially promote two distinct air masses over the forecast area this afternoon--a hot and dry airmass with dewpoints mixing out well into 60s across interior Southeast Georgia and hot and moist one with dewpoints 70+ along the coast. Highs are poised to rise quickly through the day with a few spots across interior Southeast Georgia peaking in the upper 90s with a few spots making a run for the century mark with lower- mid 90s elsewhere away from the beaches. It still appears the best chances for convection will remain across the coastal corridor in the vicinity of the sea breeze with the highest probabilities centered over the Charleston Tri-County where the strongest low-level convergence along the sea breeze and region of highest 850 hPa theta-e will be found. The mean steering flow looks rather week today so any tstms will could be slow moving and capable of producing a quick 2-3" in an hour. Minor/urban flooding is possible. A pulse severe tstm could also occur with gusty winds and frequent cloud-to-ground lightning possible. Pops will range from <10% across far interior Southeast Georgia to 20-50% along the coast, highest in the Charleston Tri-County. Tonight: Evening showers and thunderstorms will slowly come to an end as daytime heating is lost. The sea breeze will push well inland with light southeast winds. Expect low temperatures in the mid 70s inland to low 80s at the beaches. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... Tuesday: The unseasonably strong mid-level trough along the eastern third of the country in the morning will lift to the northeast as time progresses. Replacing it across the Southeastern U.S. will be the eastern periphery of High pressure centered over the Southern Plains. This will lead to rising heights over our area. The stationary surface front will remain just to our north and northwest while a surface trough will be located just inland. Additionally, Atlantic High pressure will be centered well offshore. PWATs will trend lower, with values possibly dropping to ~1.5" along the coast, and even lower far inland. Synoptic models don't have much convection in the afternoon, only pointing to isolated coverage at most. The long-range CAMS range from isolated coverage to scattered coverage. We leaned towards the isolated coverage developing near the coast and following the sea breeze inland through early evening. This is due to lower than normal instability and more dry air across our area. Any convection that manages to develop shouldn't be too strong, and is expected to dissipate around sunset, with the evening and overnight being relatively dry. The lack of convection along with the combination of rising low- level thickness values and 850 mb temperatures will also cause high temperatures to be several degrees above normal. Highs should peak in the mid to upper 90s, except cooler at the coast. Heat indices should peak around 105 degrees, mainly near the coast. Low temperatures will be a few degrees above normal. Wednesday: The mid-levels will consist of a weakening trough to our north. Replacing it will be the eastern periphery of ridging building into our region from the Southern Plains. At the surface, the stationary front just to our north should lift north and dissipate into the afternoon. Meanwhile, a surface trough will be located just inland. Additionally, Atlantic High pressure will move closer to our region, all while High pressure also briefly develops in the northeast Gulf of Mexico. PWATs will start to increase, rising to ~1.75" during the day and possibly exceeding 2" overnight. But models once again have isolated sea breeze convection, if any manages to develop given the less than ideal conditions noted by the model soundings. Any convection that manages to develop shouldn't be too strong, and is expected to dissipate around sunset. The lack of convection along with the combination of low-level thickness values and 850 mb temperatures will yield high temperatures several degrees above normal. Highs are expected to peak in the upper 90s across most of our area, with many locations making a run for the century mark. The only place with somewhat cooler temperatures will be the beach. Also, Heat indices should peak just short of 110 degrees, mainly near the coast. The only wrinkle in the forecast could be a line of storms moving from Upstate SC through northern portions of our area in the evening. Some models hint at this, while others do not. For now, we don't have this in the forecast. Otherwise, low temperatures will be several degrees above normal. Thursday: The mid-level pattern will consist of weak troughing to our north. Meanwhile, ridging across the Southern Plains will continue to reach into the Southeast U.S. The surface pattern may consist of weak troughing just inland, while Atlantic High pressure is centered well offshore. Additionally, weak High pressure may be in the northeast Gulf of Mexico. Moisture continues to increase across our area, with PWATs generally above 2". But models once again have isolated sea breeze convection, if it's able to develop. More concerning will be the temperatures. They should be even hotter than on Wednesday, with many locations rising to the century mark. Even the beaches may be in the lower 90s. Dew points will also trend upward, which will lead to higher heat indices. It's possible they could exceed 110 degrees, especially closer to the coast where there will be the highest pooling of dew points. So Heat Advisories may be needed for portions of our area. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... The periphery of the Southern Plains ridge will continue to reach into the Southeast through Thursday night, followed be weakening Friday due to a trough strengthening to our north. The trough should prevail over the eastern half of the country during the weekend. Surface troughing could persist over the Southeast into Friday, with High pressure in the Atlantic. A cold front could approach early in the weekend, possibly moving through late in the weekend. Diurnal convection is expected to increase each day into the weekend. Additionally, temperatures will be above normal through Friday, then falling to near normal for the weekend. Heat indices could reach 110 degrees Friday, which could prompt Heat Advisories before the convection develops. && .AVIATION /16Z MONDAY THROUGH FRIDAY/... 17/18z TAF discussion: KCHS/KJZI/KSAV: VFR for much of the 18z TAF period. Best chances for tstm impacts will be a KCHS where a TEMPO was refined to 22-00z based on the latest high res data. VCTS was highlighted for KJZI as data suggests the bulk of the activity will remain inland from that terminal. For KSAV, VCTS was also highlighted 22-01z, but there is a weak signal that a cluster could approach the terminal from the north roughly 23-00z. Confidence was just not high enough to keep a TEMPO group in play there. All convection should be done by 02z with VFR prevailing. Extended Aviation Outlook: Mainly VFR through Thursday. The next notable chance for brief flight restrictions due to showers/thunderstorms are Friday afternoon/evening. && .MARINE... Today and Tonight: The Bermuda-Azores High will stretch across Florida into the Gulf of Mexico, while inland a stationary front or trough meanders over the southeast United States. Southwest winds in the morning hours will slowly back from the south/ southeast as an afternoon sea breeze forms. Winds will be around 10 kts, with some gusts 15 to 20 kts. Expect seas 2 to 3 feet. Extended Marine: The synoptic pattern will consist of a stationary front just to our north through midweek, while surface troughing is near the Southeast U.S. The front will lift north on Thursday, potentially leading to stronger troughing into Friday. Additionally, Atlantic High pressure will persist offshore. Winds should generally be from the SW. Otherwise, each morning and afternoon, expect backing winds due to the sea breeze. The strongest winds will be along the land/sea interface and across the Charleston Harbor. In the evening and overnight, expect veering of the winds, with some higher gusts possible further offshore. It's not out of the question gusts could exceed 20 kt across portions of our waters Wednesday, Thursday, and Friday nights, so Small Craft Advisories can't completely be ruled out. Otherwise, seas will generally be 3-4 ft or less. Rip Currents: Monday: Various lifeguard groups observed 3 ft breakers with periods of 9 sec in the surf zone Sunday. Rip Currents were also again reported at Tybee Island. Latest wave period reported from 41004 was 5 sec and the 17.00z GFS spectral guidance also indicates that the dominant period will remain 4 or 5 sec (relaxing slightly from 9 sec). Due to the above, the moderate risk of rip currents will continue for our GA coastal zones with a low risk of rip currents across SC coastal zones for Monday. Tuesday: Wave models indicate a 1 to maybe 2 ft swell, ranging anywhere from 8-10 seconds. Experimental RCMOS points to a Low Risk while internal calculations are borderline Low/Moderate. However, Tybee Island, GA has been reporting rip currents the past few days, while we've had minimal reports from our SC beaches. With this in mind, we kept our GA beaches at a Moderate Risk, mainly due to Tybee, and went with a Low Risk at our SC beaches. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. &&
Hazardous Weather Outlook National Weather Service Charleston SC 314 AM EDT Mon Jul 17 2023 GAZ117-119-139-141-180715- Coastal Bryan-Coastal Chatham-Coastal Liberty-Coastal McIntosh- 314 AM EDT Mon Jul 17 2023 ...MODERATE RISK FOR RIP CURRENTS IN EFFECT FROM 8 AM EDT THIS MORNING THROUGH THIS EVENING... This Hazardous Weather Outlook is for southeast Georgia. .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. Moderate Risk for Rip Currents. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. Heat: Heat indices could reach 110 degrees Thursday and Friday. Heat Advisories could be needed. Rip Currents: There is a moderate risk for rip currents at Georgia area beaches for Tuesday. .SPOTTER INFORMATION STATEMENT... Spotter assistance is not anticipated at this time. SCZ048-051-180715- Beaufort-Coastal Jasper- 314 AM EDT Mon Jul 17 2023 This Hazardous Weather Outlook is for southeast South Carolina. .DAY ONE...Today and tonight. The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. Heat: Heat indices could reach 110 degrees Thursday and Friday. Heat Advisories could be needed. .SPOTTER INFORMATION STATEMENT... Spotter assistance is not anticipated at this time. GAZ087-088-099>101-114>116-118-137-138-140-SCZ040-042>045-047-049- 050-052-180715- Jenkins-Screven-Candler-Bulloch-Effingham-Tattnall-Evans- Inland Bryan-Inland Chatham-Long-Inland Liberty-Inland McIntosh- Allendale-Hampton-Inland Colleton-Dorchester-Inland Berkeley- Inland Jasper-Coastal Colleton-Charleston-Tidal Berkeley- 314 AM EDT Mon Jul 17 2023 This Hazardous Weather Outlook is for southeast Georgia and southeast South Carolina. .DAY ONE...Today and tonight. No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. Heat: Heat indices could reach 110 degrees Thursday and Friday. Heat Advisories could be needed. .SPOTTER INFORMATION STATEMENT... Spotter assistance is not anticipated at this time. AMZ330-350-352-354-374-180715- 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- 314 AM EDT Mon Jul 17 2023 This Hazardous Weather Outlook is for Atlantic coastal waters. .DAY ONE...Today and tonight. No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter assistance is not anticipated at this time.
Special Weather Statement
National Weather Service Charleston SC
135 PM EDT Mon Jul 17 2023
SCZ050-171800-
Charleston-
135 PM EDT Mon Jul 17 2023
...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF CHARLESTON COUNTY...
At 134 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm over Hampton Plantation State Park. This storm
was nearly stationary.
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...
Santee Coastal Reserve and Hampton Plantation State Park.
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.
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 3315 7952 3317 7951 3318 7949 3319 7949
3321 7947 3321 7945 3322 7945 3322 7944
3318 7940 3315 7934 3313 7934
TIME...MOT...LOC 1734Z 269DEG 2KT 3317 7945
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPHSpecial Weather Statement
National Weather Service Charleston SC
220 PM EDT Mon Jul 17 2023
GAZ141-171845-
Coastal McIntosh-
220 PM EDT Mon Jul 17 2023
...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF MCINTOSH COUNTY...
At 220 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm over Blackbeard Island, or 15 miles northeast of
Darien, moving east at 10 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...
Blackbeard Island, Valona, and Sapelo Island.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Excessive cloud to ground lightning is occurring with this storm.
Lightning can strike 15 miles away from a thunderstorm. Seek safe
shelter inside a building or vehicle.
&&
LAT...LON 3144 8136 3160 8130 3159 8119 3156 8120
3154 8118 3156 8118 3157 8116 3157 8115
3153 8115 3139 8123
TIME...MOT...LOC 1820Z 285DEG 10KT 3151 8123
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPHThe Charleston,SC radar (KCLX), 65 km away, was scanning. The volume nearest the first event began at 18:46 UTC.
1 lightning. Local standard time, as filed.
Local broadcast media shared a story of a lightning strike at Central Missionary Baptist Church in Savannah. The lightning strike produced a fire in the building and caused a large portion of the roof to collapse.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Georgia in 2023Every state in 2023This day in weather historyWarnings in Georgia, July 2023
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: 1124047.