A frontal system over the area on August 18th allowed for the development of rain early in the morning. As the day progressed, mesoscale features including multiple boundary interactions and a mesolow allowed thunderstorms to continue to intensify with persistent back-building and training over the same areas in southern Connecticut.
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 OKX wrote it up.
A frontal system over the area on August 18th allowed for the development of rain early in the morning. As the day progressed, mesoscale features including multiple boundary interactions and a mesolow allowed thunderstorms to continue to intensify with persistent back-building and training over the same areas in southern Connecticut. These thunderstorms produced anywhere from 3-4.5 inch per hour rainfall rates resulting in several considerable Flash Flood Warnings and a Flash Flood Emergency being issued. Numerous rescues, road and bridge washouts, and several mudslides resulted in widespread damage. Several large-stem rivers including the Naugatuck, Pomperaug, Housatonic, and Still Rivers all reached major flood stage at some point during the day as a result of a widespread 5-8 inches of rainfall with localized amounts of up to 12-13 inches. Unfortunately, 3 people lost their lives in Connecticut as a result of the flash flooding.
Preliminary damage assessment costs for Fairfield County is $5.8 million and New Haven County is $4 million. This is not a final number.
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 New York, NY wrote its last area forecast discussion before the first event at Aug 18, 6:50 AM EST, 2 hours 40 minutes earlier.
Area Forecast Discussion
National Weather Service New York NY
750 AM EDT Sun Aug 18 2024
.SYNOPSIS...
Low pressure tracks slowly eastward through the Great Lakes
today as a secondary low develops over the Mid Atlantic. This low
moves north and east into the local area tonight, sending a cold
front through the area Monday. A secondary frontal passage moves
through Tuesday. High pressure then builds in for the middle and
end of the week.
&&
.NEAR TERM /THROUGH TONIGHT/...
Slow moving frontal system tracks into the region today, bringing
a couple rounds of heavy rainfall with it.
Ribbons of showers, some moderate to heavy, have moved into the
region this morning. This activity could produce locally heavy
downpours that result in flooding. In addition, with recent
thunderstorms over SE PA and NJ, have included the mention of
possible thunder in a corridor extending northward thru NJ into
NYC and the Lower Hudson Valley. A quick inch of rainfall is
possible with this activity, and could lead to urban and poor
drainage flooding depending on placement and duration.
This entire system will be slow moving eastward as downstream ridging
remains across the western North Atlantic. A frontal wave
develops along the Mid Atlantic coast into this evening, before
pushing north into the local area. This low provides lift for
additional heavy rainfall later today and tonight. Limited
shear and instability should keep activity mainly sub-severe and
disorganized, but can't rule out thunderstorms. Of greater
concern is the potential for training convection and heavy
downpours that lead to flooding. PWATs already over 1.5 inches
in the OKX 00Z sounding increases toward 2 inches today, and
efficient warm cloud processes could allow for elevated rainfall
rates with this activity. 00Z HREF signals the potential for
rainfall rates perhaps as high as 2 inches in an hour, especially
over New Jersey and Lower Hudson Valley zones. While total QPF
looks to average a general 1 to 2 inches for locations along and
west of the Hudson River, including the NYC metro, localized
amount could approach 3 or 4 inches depending on placement and
training of cells.
All this said, the Flood Watch remains in effect through late
tonight for zones west of the Hudson River for the potential of
scattered flash flooding, urban and poor drainage flooding, and
possibly flooding of faster responding streams in NE NJ. Areas to
the east look to miss out on the axis of heaviest rainfall based on
latest hi-res guidance, so opted not to expand the watch any further
east with this update. Certainly, if the axis shifts a bit east,
or if training convection develops, flooding could be an issue
here as well, including in NYC and urban centers. WPC has kept
the slight risk for excessive rainfall in place for similar
areas, expanding just a bit to the east to include the entire
NYC metro and SE CT.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
An unsettled start to the work week as the upper trough and
frontal system continue to impact the region.
Cold front and weak coastal wave of low pressure approach on
Monday as the trough axis begins to shift into the Northeast.
Another round of showers and possible thunderstorms likely
Monday into Monday night. This will mainly be associated with
the cold front, but the nearby low could enhanced rainfall.
Still some uncertainty on severity and placement, but there will
remain a threat for locally heavy rainfall, nuisance flooding,
and an isolated flash flooding occurrence.
The area remains under a broad trough with vorticity maxima
moving through Monday night and into Tuesday. As the trough
tries to lift during the day on Tuesday, additional energy
descends from the north to allow for another round of forcing.
At the surface, this should translate into the form of a
secondary frontal passage that brings another round of showers
with possible embedded thunderstorms, especially Monday night
into Tuesday morning. Any residual showers should diminish into
the afternoon on Tuesday with the passage of the surface cold
front. This will set the stage for drier and cooler conditions
to take hold into midweek. Behind the fropa, highs on Tuesday
could be the coolest since late May for some, generally in the
upper 60s and lower 70s.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
No significant changes in the long term. A drier, cooler pattern
develops midweek behind the frontal system as dry air advects
south with surface high pressure building in. Lingering trough
over the Northeast may persist into late week, reinforced by a
closed upper low dropping south out of Canada.
This high pressure will be accompanied with primarily N/NW winds
and a much cooler regime, perhaps the coolest since late spring.
High temperatures Wednesday may not rise out of the low 70s for
much of the area. Lows Wednesday night and Thursday night will
likely be fairly chilly, with some locations for the interior
and outlying areas possibly dropping into the low 50s or upper
40s, depending on the strength of any radiational cooling.
Temperatures will gradually moderate into late week and the
weekend with highs by Friday and Saturday rising back into the
upper 70s to low 80s.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
A frontal system slowly approaches the terminals through the TAF
period.
Mostly VFR today. Showers possible at any time, but for the
city terminals as points west, better chances return late this
afternoon/early evening. Farther east, showers for KBDR and KISP
during the morning and perhaps KGON before better chances return
tonight.
Iso TSTM today, but better overall chances late this afternoon
and evening.
Winds will be mainly SE around 10 kt or less through the TAF
period. Coastal terminals could see winds a few kt higher at
times, especially this afternoon.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Chance of a few gusts 15-20 kt late morning and during the
afternoon. Chance of VFR for a few hours this afternoon.
Amendments possible for showers/potential thunderstorms at any
time through tonight.
Timing of PROB30 TSRA late day and evening may be off by a few
hours with the threat perhaps an hour or two later than shown in
TAFS.
OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY...
Monday: Showers with possible thunderstorms, especially
afternoon and evening. MVFR or lower at times.
Tuesday: Mainly VFR. A chance of showers with MVFR possible. NW
wind gusts 15-20 kt.
Wednesday-Thursday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
Rough ocean seas and long period swells, 12 to 15 second, will
persist through Monday as distant TC Ernesto passes well
offshore in the open Atlantic. This is also leading to rough
conditions around inlets. Please refer to the National Hurricane
Center for official forecasts regarding Ernesto. A Small Craft
Advisory remains in effect for the ocean zones thru Monday
night. Seas on the eastern LI Sound could also approach 5 ft at
times today, though thinking this may be more occasional.
Thereafter, elevated wave heights on the ocean zones will allow
for SCA conditions to continue Monday night and possibly into
the day on Tuesday. By Late Tuesday, wind diminish and wave
heights should fall below 5 feet. Sub-SCA conditions are then
expected with high pressure moving into the area by midweek.
&&
.HYDROLOGY...
A Flood Watch remains in effect thru late tonight for NE New
Jersey and into the Lower Hudson Valley west of the Hudson
River. Isolated to scattered instances of flash flooding are
possible across the more flood prone areas of NE NJ and adjacent
areas of the Lower Hudson Valley, and perhaps as far east as
NYC. Locally heavy rainfall is possible, mainly this morning,
and again this late today into tonight, with rainfall rates up
to an inch or two per hour. Farther east, the risk for flash
flooding is lower, but cannot be entirely ruled out. Ponding and
poor drainage flooding is the most likely solution here with
any heavier activity.
Additional rainfall expected on Monday and Monday night will
lead to a more widespread threat for localized flash flooding,
along with nuisance flooding of urban and poor drainage areas.
Total rainfall through Monday night ranges from around a half
inch east to between 1 and 2 inches from NYC metro on north and
west. Locally higher amounts, possibly up to 3 or 4 inches, are
possible across northeastern New Jersey into the Lower Hudson
Valley.
No hydrologic concerns Tuesday through next weekend.
&&
.TIDES/COASTAL FLOODING...
A high rip current risk is in place through Monday due to elevated,
long period swells from passing TC Ernesto.
Ocean seas are forecast to be highest today and Monday, and
with surf heights up to 6 ft, local beach erosion is possible.
A full moon on Monday as well as swell from distant TC Ernesto
will elevated tide levels today into early this week. Minor
coastal flooding is expected with high tide this evening across
the back bays of Nassau and Western Sound along the southwest CT
and S Westchester coast. Have issued a Coastal Flood Advisory
for these locations. Localized minor coastal flooding is
possible across southern Queens, Southern Brooklyn and lower NY
Harbor. Locations may just touch minor benchmarks and a
statement has been issued. Additional minor flooding is possible
for high tide Monday evening and statements/Advisories will
likely be needed for similar locations as with high tide this
evening.
Please refer to NHC for official forecasts regarding Hurricane
Ernesto.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Coastal Flood Advisory from 10 PM this evening to 1 AM EDT
Monday for CTZ009.
NY...Coastal Flood Advisory from 10 PM this evening to 1 AM EDT
Monday for NYZ071.
Flood Watch through late tonight for NYZ067-069.
High Risk for Rip Currents through Monday evening for NYZ075-080-
081-178-179.
Coastal Flood Advisory from 7 PM to 10 PM EDT this evening for
NYZ179.
NJ...Flood Watch through late tonight for NJZ002-004-006-103>108.
MARINE...Small Craft Advisory until 6 AM EDT Tuesday for ANZ350-353-355.
&&
SYNOPSIS...DR
NEAR TERM...DR
SHORT TERM...DR
LONG TERM...MW
AVIATION...JC
MARINE...DR
HYDROLOGY...DR
TIDES/COASTAL FLOODING...Hazardous Weather Outlook National Weather Service New York NY 344 AM EDT Sun Aug 18 2024 NJZ002-004-006-103>108-NYZ067-069-191000- Western Passaic-Eastern Passaic-Hudson-Western Bergen-Eastern Bergen- Western Essex-Eastern Essex-Western Union-Eastern Union-Orange- Rockland- 344 AM EDT Sun Aug 18 2024 ...FLOOD WATCH REMAINS IN EFFECT THROUGH LATE TONIGHT... This Hazardous Weather Outlook is for northeast New Jersey and southeast New York. .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. Flood Watch. .DAYS TWO THROUGH SEVEN...Monday through Saturday. No hazardous weather is expected at this time that would meet NWS warning criteria. .SPOTTER INFORMATION STATEMENT... Spotter activation will likely be needed. && This Hazardous Weather Outlook provides a summary of potential widespread hazardous weather events that may reach NWS warning criteria. Most long fused NWS watches, warnings, and advisories in effect are highlighted. Please refer to the latest NWS forecasts for weather not meeting NWS warning criteria. NYZ080-081-191000- Southwest Suffolk-Southeast Suffolk- 344 AM EDT Sun Aug 18 2024 ...HIGH RIP CURRENT RISK IN EFFECT THROUGH MONDAY EVENING... This Hazardous Weather Outlook is for southeast New York. .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. High Rip Current Risk. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. High Rip Current Risk. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. && This Hazardous Weather Outlook provides a summary of potential widespread hazardous weather events that may reach NWS warning criteria. Most long fused NWS watches, warnings, and advisories in effect are highlighted. Please refer to the latest NWS forecasts for weather not meeting NWS warning criteria. CTZ006>008-010>012-NYZ078-079-191000- Northern New Haven-Northern Middlesex-Northern New London- Southern New Haven-Southern Middlesex-Southern New London- Northwest Suffolk-Northeast Suffolk- 344 AM EDT Sun Aug 18 2024 This Hazardous Weather Outlook is for southern Connecticut and southeast New York. .DAY ONE...Today and tonight. No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Monday through Saturday. No hazardous weather is expected at this time that would meet NWS warning criteria. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. && This Hazardous Weather Outlook provides a summary of potential widespread hazardous weather events that may reach NWS warning criteria. Most long fused NWS watches, warnings, and advisories in effect are highlighted. Please refer to the latest NWS forecasts for weather not meeting NWS warning criteria. ANZ331-332-335-338-340-345-350-353-355-191000- Long Island Sound East of New Haven CT/Port Jefferson NY to the Mouth of the Connecticut River- Long Island Sound East of the Mouth of the Connecticut River- Long Island Sound West of New Haven CT/Port Jefferson NY- New York Harbor-Peconic and Gardiners Bays- South Shore Bays from Jones Inlet through Shinnecock Bay- Moriches Inlet NY to Montauk Point NY out 20 nm- Fire Island Inlet NY to Moriches Inlet NY out 20 nm- Sandy Hook NJ to Fire Island Inlet NY out 20 nm- 344 AM EDT Sun Aug 18 2024 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...Monday through Saturday. No hazardous weather is expected at this time that would meet NWS warning criteria. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. && This Hazardous Weather Outlook provides a summary of potential widespread hazardous weather events that may reach NWS warning criteria. Most long fused NWS watches, warnings, and advisories in effect are highlighted. Please refer to the latest NWS forecasts for weather not meeting NWS warning criteria. CTZ005-NYZ068-070-072>074-176-177-191000- Northern Fairfield-Putnam-Northern Westchester-New York (Manhattan)- Bronx-Richmond (Staten Island)-Northern Queens-Northern Nassau- 344 AM EDT Sun Aug 18 2024 This Hazardous Weather Outlook is for southern Connecticut and southeast New York. .DAY ONE...Today and tonight. Isolated to scattered instances of flash flooding are possible today and tonight. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Hazardous weather is not expected at this time that would meet NWS warning criteria. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed. && This Hazardous Weather Outlook provides a summary of potential widespread hazardous weather events that may reach NWS warning criteria. Most long fused NWS watches, warnings, and advisories in effect are highlighted. Please refer to the latest NWS forecasts for weather not meeting NWS warning criteria. CTZ009-NYZ071-191000- Southern Fairfield-Southern Westchester- 344 AM EDT Sun Aug 18 2024 ...COASTAL FLOOD ADVISORY IN EFFECT FROM 10 PM THIS EVENING TO 1 AM EDT MONDAY... This Hazardous Weather Outlook is for southern Connecticut and southeast New York. .DAY ONE...Today and tonight. Isolated to scattered instances of flash flooding are possible today and tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Coastal Flood Advisory. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Hazardous weather is not expected at this time that would meet NWS warning criteria. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed. && This Hazardous Weather Outlook provides a summary of potential widespread hazardous weather events that may reach NWS warning criteria. Most long fused NWS watches, warnings, and advisories in effect are highlighted. Please refer to the latest NWS forecasts for weather not meeting NWS warning criteria. NYZ075-178-191000- Kings (Brooklyn)-Southern Queens- 344 AM EDT Sun Aug 18 2024 ...HIGH RIP CURRENT RISK IN EFFECT THROUGH MONDAY EVENING... This Hazardous Weather Outlook is for southeast New York. .DAY ONE...Today and tonight. Isolated to scattered instances of flash flooding are possible today and tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. High Rip Current Risk. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. High Rip Current Risk. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed. && This Hazardous Weather Outlook provides a summary of potential widespread hazardous weather events that may reach NWS warning criteria. Most long fused NWS watches, warnings, and advisories in effect are highlighted. Please refer to the latest NWS forecasts for weather not meeting NWS warning criteria. NYZ179-191000- Southern Nassau- 344 AM EDT Sun Aug 18 2024 ...HIGH RIP CURRENT RISK IN EFFECT THROUGH MONDAY EVENING... ...COASTAL FLOOD ADVISORY IN EFFECT FROM 7 PM TO 10 PM EDT THIS EVENING... This Hazardous Weather Outlook is for southeast New York. .DAY ONE...Today and tonight. Isolated to scattered instances of flash flooding are possible today and tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. High Rip Current Risk. Coastal Flood Advisory. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. High Rip Current Risk. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed. && This Hazardous Weather Outlook provides a summary of potential widespread hazardous weather events that may reach NWS warning criteria. Most long fused NWS watches, warnings, and advisories in effect are highlighted. Please refer to the latest NWS forecasts for weather not meeting NWS warning criteria.
The Brookhaven radar (KOKX), 61 km away, was scanning. The volume nearest the first event began at 14:33 UTC.
34 flash flood. Local standard time, as filed.
Dozens of road closures and fire department water rescues throughout the town.
Video showing running water from the Goodwives river out of its banks in the Old Kings market shopping center and along Old Kings highway in Darien. Road closure at Old Kings highway N and Sedgewick Ave.
Multiple road closures in the town of Ridgefield. Roads impassable with 1 to 3 feet of water deep in spots.
Mudslide on Shelter Rock Road in Danbury has caused a major gas leak and evacuations in the Woodland Hills Complex.
Route 172 all lanes closed due to flooding.
Route 6/67 all lanes closed due to flooding.
Pickup truck and camper submerged in Aspectuck River near Sawmill Road. Nearby bridge washed out. Deceased male located downstream from submerged vehicle.
Substantial river flooding Five Mile river at River St. Several roads closed in town due to debris or flooding.
Photos of cars partially submerged.
Pictures on social media along Route 67 near Pepper Tree Lane in Southbury. Debris all over road and trees down due to flood waters. Stranded vehicle off the road.
Route 53 closed between Weston Road and Newtown Turnpike because of washout.
Route 53 closed both directions at Glen Road because of washouts.
Route 53 closed at Valley Forge Road because of washout.
Old Waterbury Road at Old Highway closed due to flooding.
Portions of Old Waterbury Road being washed away due to flood waters.
Flooding at Weed Road and Walnut Hill Road.
Picture and video on social media of Bennetts Bridge Road in Sandy Hook washed out.
Multiple motorists stranded with water rescues ongoing in Monroe. Fire department responding with extra equipment to assist with the rescues.
Route 6 closed between I-84 and Old Hawleyville Road due to flooding.
Multiple docks and boats ripped from shore and floating down river at Lake Housatonic. Road washed out and closed nearby.
Two women women were swept away by rising floodwaters. Both have been reported as fatalities.
Route 34 is closed at Loughlin Road due to a washout.
Flood waters stranded multiple motorists on Oxford Road near the Brookside Inn. People inside a nearby home and the restaurant are being rescued.
Dozens campers trapped in Kettletown State Park due to walking and road bridges being washed away.
Picture and video on social media showing a house on E Hill Road collapsing into the Fivemile Brook in Oxford.
Video of Roosevelt Drive in Monroe washed out near Lake Zoar drive-in.
Picture on social media of train tracks undermined on the Waterbury branch of the Metro-North New Haven line near Seymour.
Numerous vehicles trapped in flood waters with multiple rescues ongoing along Oxford Road and Roosevelt Drive.
Route 188 closed between Hulls Hill Road and Edmonds Road because of a mudslide.
CONN DOT reports Route 6 closed at Commerce Road because of a washout.
Four buildings along the Naugatuck River are compromised by flooding and are being evacuated.
Route 34 closed at Jefferson Street because of a mudslide.
Route 53 at Diamond Hill Road closed due to flooding.
Franklin Street closed at Wakelee Ave due to flooding.
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Flash Flood, Fairfield | 2024-08-18 | Male | Camping | Direct | |
| Flash Flood, New Haven | 2024-08-18 | Female | Vehicle/Towed Trailer | Direct | |
| Flash Flood, New Haven | 2024-08-18 | Female | Vehicle/Towed Trailer | Direct |
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Connecticut in 2024Every state in 2024This day in weather historyWarnings in Connecticut, August 2024
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: 1213873, 1213874, 1213875, 1213876, 1213877, 1213878, 1213879, 1213880, 1213881, 1213882, 1213885, 1213886, 1213887, 1213888, 1213889, 1213890, 1213891, 1213892, 1213893, 1213894, 1213895, 1213896, 1213897, 1213898, 1213899, 1213900, 1213901, 1213902, 1213903, 1213904, 1213905, 1213906, 1213907, 1213908.