Thunderstorms with heavy rain developed between 2 AM and 4 AM in an area of stronger convergence off Lake Erie in southern Erie County. Automated gauges from weather underground were helpful to get ground truth rainfall reports.
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 BUF wrote it up.
Thunderstorms with heavy rain developed between 2 AM and 4 AM in an area of stronger convergence off Lake Erie in southern Erie County. Automated gauges from weather underground were helpful to get ground truth rainfall reports. Repeated heavy rain resulted in flash flooding in the Southern Tier. Multiple road closures were reported. Areal flooding lingered after the flash flood. The heaviest rain hit the headwaters of the east and west branches of Cazenovia Creek, resulting in very high flows into the early afternoon. The gage EBZN6 quickly rose over 6 feet to around 9 feet in just two hours.
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 Buffalo, NY wrote its last area forecast discussion before the first event at Jul 14, 3:32 AM EST, 14 minutes earlier.
Area Forecast Discussion National Weather Service Buffalo NY 432 AM EDT Wed Jul 14 2021 .SYNOPSIS... Scattered showers and a few thunderstorms are possible ahead of a weak cold front today. The best chance for thunderstorms will be east of the Genesee Valley late morning into early afternoon. Less humid today with temperatures reaching the upper 70s to low 80s. Mostly dry Thursday however heat and humidity return. Showers and thunderstorms return Thursday night. && .NEAR TERM /THROUGH TONIGHT/... Regional radar shows scattered showers and a few storms across the region this morning. There is a line of training showers and storms across far northern Chautauqua and southern Erie counties. A Flash Flood Warning is in effect for this localized area. Heavy rain and lightning are expected in this activity through rush hour. A weak cold front resides across southern Ontario this morning. Elevated instability of 500 J/kg and 30 knots of 0-6kts of bulk shear in a moist environment has fueled showers and a few storms overnight. An area of training storms from the Lake Erie shoreline of northern Chautauqua county to southern Erie county is just ahead of the front producing increased convergence. The front will move into western NY this morning and showers and storms will track east into the Genesee Valley and Finger Lakes however flash flooding is not expected further east. Showers across Lake Ontario and the Saint Lawrence Valley will move east across the North Country this morning. The wind field aloft will decrease late this morning as the upper level trough moves into the region. Abundant cloud cover as the front moves through the region today will suppress instability. Additional showers and storms are possible from the Finger Lakes into the western Adirondacks however most of the activity will be east of the Finger Lakes. A few showers and storms may form along lake breeze boundaries, behind the front this afternoon. Cooler today with temperatures reaching the upper 70s to low 80s. Mostly dry tonight with lows in the low to mid 60s to the upper 60s near the lakeshores. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... Upper level trough over the Great Lakes Thursday will support the development of an area of low pressure over the northern Great Lakes with a cold front extending through the central Great Lakes and into the Midwest. Drier air and a capping inversion will initially be in place Thursday, before slowly eroding by late in the day. We will have to watch for how convection along and ahead of the front develops into the area by Thursday night as there could be some limited severe potential. Better chance for more widespread coverage of showers and thunderstorms arrives Friday into Friday night as the cold front slowly pushed through the area. && .LONG TERM /SATURDAY THROUGH TUESDAY/... An upper level trough will move overhead while the front slows down as it moves into Pennsylvania and central NY Saturday. This will promote the chance for showers across the region with better coverage across interior portions of the forecast area. Storms are also possible in vicinity of the front. The upper level trough and front will linger with the chance of showers and storms lasting through the weekend. Temperatures will fall to near-normal through the weekend. High pressure likely Monday with mostly dry conditions expected, except for a few showers possible late Monday for the eastern portions of the area. Mostly dry conditions for Tuesday as well, but a few scattered showers can't be ruled out. && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... Scattered showers will continue overnight with the chance for thunderstorms. A surface trough will track across the region this morning. Showers and a few thunderstorms are possible. An uptick in moisture will cause MVFR ceilings through the morning hours. IFR ceilings likely across the higher terrain including KJHW through the morning. Showers and any thunderstorms will move into central NY by early afternoon and drier air will move into western and north central NY. A few showers may linger along lake breeze boundaries south of Lake Ontario through the afternoon. VFR conditions expected Wednesday afternoon into this evening. Outlook... Thursday through Saturday...Mainly VFR. A chance of showers and thunderstorms in the afternoon. && .MARINE... Moderate southwesterlies will be found throughout the region with thunderstorms possible. While choppy conditions will be possible at times on Lake Erie...small craft advisory conditions are not expected to be met. A narrow window of fair weather will be in place for Thursday with moderate southerlies and manageable waves in the forecast. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && SYNOPSIS...HSK NEAR TERM...HSK SHORT TERM...TMA LONG TERM...HSK/SW AVIATION...HSK MARINE...HSK/RSH
Hazardous Weather Outlook National Weather Service Buffalo NY 1103 PM EDT Tue Jul 13 2021 NYZ001>008-010>014-019>021-085-150315- Niagara-Orleans-Monroe-Wayne-Northern Cayuga-Oswego-Jefferson-Lewis- Northern Erie-Genesee-Wyoming-Livingston-Ontario-Chautauqua- Cattaraugus-Allegany-Southern Erie- 1103 PM EDT Tue Jul 13 2021 This Hazardous Weather Outlook is for western and north central New York. .DAY ONE...Tonight. No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. Thunderstorms on Wednesday could contain another round of torrential downpours, especially east of the Genesee valley. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. This product, along with other watches, warnings, advisories, and statements issued by the National Weather Service office in Buffalo can be found on the internet at http://www.weather.gov/buf LEZ020-040-041-LOZ030-042>045-062>065-SLZ022-024-150315- Upper Niagara River and Buffalo Harbor- Lake Erie nearshore waters from Ripley to Dunkirk- Lake Erie nearshore waters from Dunkirk to Buffalo- Lower Niagara River- Lake Ontario nearshore waters from the Niagara River to Hamlin Beach- Lake Ontario nearshore waters from Hamlin Beach to Sodus Bay- Lake Ontario nearshore waters from Sodus Bay to Mexico Bay- Lake Ontario nearshore waters from Mexico Bay to the Saint Lawrence River- Lake Ontario open waters from the Niagara River to Hamlin Beach- Lake Ontario open waters from Hamlin Beach to Sodus Bay- Lake Ontario open waters from Sodus Bay to Mexico Bay- Lake Ontario open waters from Mexico Bay to the Saint Lawrence River- Saint Lawrence River from Cape Vincent to Ogdensburg- Saint Lawrence River from Ogdensburg to Saint Regis- 1103 PM EDT Tue Jul 13 2021 This Hazardous Weather Outlook is for the New York waters of Lake Erie, Lake Ontario, and the Saint Lawrence River. .DAY ONE...Tonight. No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. This product, along with other watches, warnings, advisories, and statements issued by the National Weather Service office in Buffalo can be found on the internet at http://www.weather.gov/buf
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BUFFALO NY
1051 PM EDT TUE JUL 13 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0719 PM TSTM WND DMG 4 SSE CHURCHVILLE 43.05N 77.85W
07/13/2021 MONROE NY LAW ENFORCEMENT
TREES AND WIRES DOWN IN THE WHEATLAND AREA.
0736 PM TSTM WND DMG 1 S GATES-NORTH GATES 43.15N 77.70W
07/13/2021 MONROE NY LAW ENFORCEMENT
TREES AND WIRES DOWN IN GATES.
0742 PM TSTM WND DMG GREECE 43.21N 77.70W
07/13/2021 MONROE NY LAW ENFORCEMENT
TREES AND WIRES DOWN IN GREECE.
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BUFFALO NY
1136 PM EDT TUE JUL 13 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1030 PM TSTM WND DMG 1 ENE OSCEOLA 43.50N 75.70W
07/13/2021 LEWIS NY LAW ENFORCEMENT
TREES AND WIRES DOWN ON OSCEOLA RD.
1104 PM TSTM WND DMG 7 NE CROGHAN 43.96N 75.27W
07/13/2021 LEWIS NY LAW ENFORCEMENT
TREES AND WIRES DOWN ON LONG POND RD.
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BUFFALO NY
1240 AM EDT WED JUL 14 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0915 PM TSTM WND DMG HANNIBAL 43.32N 76.58W
07/13/2021 OSWEGO NY LAW ENFORCEMENT
TREES DOWN IN THE TOWN OF HANNIBAL. TIME
ESTIMATED BY RADAR.
0920 PM TSTM WND DMG OSWEGO 43.46N 76.50W
07/13/2021 OSWEGO NY LAW ENFORCEMENT
TREES DOWN IN OSWEGO. TIME ESTIMATED BY
RADAR.
0950 PM TSTM WND DMG PARISH 43.40N 76.13W
07/13/2021 OSWEGO NY LAW ENFORCEMENT
TREES DOWN IN THE TOWN OF PARISH. TIME
ESTIMATED BY RADAR.
0950 PM TSTM WND DMG 3 SSE PARISH 43.37N 76.11W
07/13/2021 OSWEGO NY LAW ENFORCEMENT
ABOUT 20 TREES DOWN ON SMITH RD. NEAR CR 84
IN THE TOWN OF HASTINGS. TIME ESTIMATED BY
RADAR.
&&The Buffalo radar (KBUF), 62 km away, was scanning. The volume nearest the first event began at 08:45 UTC.
2 flash flood. Local standard time, as filed.
Route 5 was reported to be closed due to flooding from Harrington Road to Center Road.
Road was closed due to flooding.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in New York in 2021Every state in 2021This day in weather historyWarnings in New York, 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: 976461, 976462.