An upper level disturbance in close proximity to a departing warm front triggered numerous severe thunderstorms across Northern New Jersey. A tornado touched down in Bethany to North Haven in New Haven County.
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.
An upper level disturbance in close proximity to a departing warm front triggered numerous severe thunderstorms across Northern New Jersey. A tornado touched down in Bethany to North Haven in New Haven County. Also, multiple microbursts affected parts of New Haven County which included, East Haven, North Haven, the Branfords, and Guilford.
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 27, 1:42 PM EST, 1 hour 6 minutes earlier.
Area Forecast Discussion National Weather Service New York NY 242 PM EDT Thu Aug 27 2020 .SYNOPSIS... A warm front becoming stationary north of the area this afternoon into Friday. The remnants of Laura are expected to impact the area Saturday. Fair weather is then expected into the beginning of next week. && .NEAR TERM /THROUGH TONIGHT/... **Potential for significant severe thunderstorms this afternoon into evening** A warm front, has pushed northeast of all but SE CT this afternoon, with marginal to moderate instability development across the SW half of CWA, slowly building NE through the afternoon. This building instability is being aided by strong surface heating and steep mid level lapse rates advecting in. Instability combined with strong low-mid level wind fields and deep layer shear values in the 50-60 kt range continue to warrant the SPC Enhanced Risk for severe weather. This means there is potential for a few particularly intense thunderstorms, bringing potential for destructive wind (75 mph or greater), large hail (2 inch diameter or larger), as well as an isolated tornado. Supercells are already developing over central and western NY this afternoon, and expected to increase in coverage across Central NY into southern New England along the stalled boundary by late afternoon thanks to approaching shortwave energy and right rear quad of upper jet. A potentially tornadic supercell entering Ulster County NY, feeding on enhanced helicity along warm front, could enter interior SW CT by around 4pm if it hold together. These storms will continue to sink S/SE across the area during the late afternoon hours into the evening. Discrete supercells will initially have potential for damaging to destructive winds (75+ mph) and large hail (2+"). Isolated tornadoes are possible as well, particularly in vicinity of enhanced helicity/vorticity of warm front, differential heating boundaries, and river valleys. The storms are likely to organize into several clusters, bowing segments or QLCS by this evening, with damaging to destructive winds being the primary threat. Isolated brief tornado threat would still exists as well for much of the area. Overall, think the best time range for storms remains roughly 3-7pm for Lower Hud and S CT, and 5 to 9 pm for NYC/NE NJ and LI. Once precipitation clears the coast by around 11pm the rest of the overnight period should be quiet, with perhaps a few lingering showers through around 2am. High temperatures today will range from the low to mid 90s across New York City and northeast New Jersey, to the mid to upper 70s across portions of New London County where the warm front may not lift fully through. With dew points rising into the upper 60s to around 70, this will result in heat index values rising into the mid and perhaps upper 90s in and around NE NJ and NYC. Overnight lows will range from the upper 60s in outlying areas to the low to mid 70s elsewhere. There is a moderate risk of rip current development at Atlantic Ocean beaches today, although it could become high late. && .SHORT TERM /FRIDAY/... With the next system to impact the area for the weekend remaining over the center of the country, Friday is expected to remain mostly dry to start. A few showers could then work into the area by afternoon, especially west of New York City. Highs will once again be above normal, rising to around 90 in and around the city and the mid to upper 80s elsewhere. Slightly lower temperatures combined with slightly lower dew points should keep heat index values in the upper 80s to lower 90s, just below advisory criteria. There is a moderate risk of rip current development at Atlantic Ocean beaches on Friday. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Shower chances will increase Friday night as an upper level trough approaches. The remnants of Laura are progged to be absorbed into the flow by that time, with the moisture and trof arriving Sat and Sat ngt. This aligns with the official NHC track placing the remnant low s of Nantucket 7 am Sun. Pops were limited to likely based on uncertainty this far out, and also because the 12Z ECMWF, which is much closer to the NHC track, is less bullish on hvy rainfall. High pres builds in Sun and Mon behind the sys with fair wx expected. The high builds offshore on Tue. The GFS hammers the cwa with tstms on the lljet late Mon ngt into Tue mrng, then again with aftn/eve tstms as a deep trof overspreads the region. The ECMWF is significantly more benign, leading to a very low confidence Tue and beyond. A blended approach was therefore used, with the NBM as a baseline but pops limited at slight chance. For temps, slightly cooler with the rain chances on Sat, then a cooler airmass builds in Sun-Mon. A slight warming trend Tue and Wed as heights build. The NBM with local adjustments was used for temps. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... ***HIGH IMPACT WEATHER EVENT EXPECTED THIS AFTERNOON AND EVENING DUE TO SCATTERED TO NUMEROUS SEVERE THUNDERSTORMS*** A wave of low pressure will move along a nearly stationary front from the mid Hudson Valley into southeastern Connecticut this afternoon into this evening accompanied by thunderstorms. Some thunderstorms will be strong to severe. If storms do become severe, gusts of 50 kt or higher are possible along with hail. Duration of these conditions would be an hour or less for any thunderstorm. Some uncertainty remains in the exact location and timing of these storms. MVFR is likely, and IFR possible, in these storms. Otherwise VFR will continue through the forecast period There is a chance of MVFR at KSWF and KGON late tonight with fog and stratus. Gusty southwest winds to 25 kt into early this evening shift to west and northwest as the frontal boundary sags through the terminals. Winds shift back to west less than 10 kt late this evening. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... There is medium to high confidence in a line of showers and thunderstorms moving in from the north this afternoon into this evening. However, timing uncertainty of 1 to 2 hours remains for any specific terminal to have thunderstorms. Amendments are likely for changing flight categories and convective timing and location. .OUTLOOK FOR 18Z FRIDAY THROUGH MONDAY... .Friday...VFR. Chance of showers and thunderstorms in the afternoon with local MVFR. .Friday night-Saturday...Mainly VFR to start, then MVFR or lower possible with showers and tstms. .Sunday-Tuesday...VFR. A chance of afternoon thunderstorms Tuesday. Detailed information, including hourly TAF wind component forecasts, can be found at: http:/www.weather.gov/zny/n90 && .MARINE... Marginal SCA conditions this afternoon into evening for all nearshore waters with occasional 25 kt gusts. Thereafter conds are expected to remain primarily below SCA criteria into the day on Saturday, although seas could briefly approach 5 feet for several hours this evening and again on Friday morning, primarily east of Moriches Inlet. Winds and seas will increase on the ocean this weekend due to the passing remnants of Laura. Conditions are expected to remain blw sca lvls on Mon, but may creep up close to advy lvls on the ocean on Tue. && .HYDROLOGY... Localized flash flood threat this afternoon into evening with any training convection, otherwise mainly a minor urban and poor drainage flood threat with expected faster movement of storms. The remnants of Laura are progged to impact the area in the Sat-Sat ngt time period. 1-2 inches of rain are possible, which could lead to some minor urban and poor drainage flooding. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && SYNOPSIS...FEB/JMC NEAR TERM...NV SHORT TERM...FEB LONG TERM...FEB/JMC AVIATION...MET MARINE...NV HYDROLOGY...FEB/JE
Hazardous Weather Outlook National Weather Service New York NY 326 AM EDT Thu Aug 27 2020 CTZ005>012-NJZ002-004-006-103>108-NYZ067>075-078>081-176>179-280730- Northern Fairfield-Northern New Haven-Northern Middlesex- Northern New London-Southern Fairfield-Southern New Haven- Southern Middlesex-Southern New London-Western Passaic- Eastern Passaic-Hudson-Western Bergen-Eastern Bergen-Western Essex- Eastern Essex-Western Union-Eastern Union-Orange-Putnam-Rockland- Northern Westchester-Southern Westchester-New York (Manhattan)-Bronx- Richmond (Staten Island)-Kings (Brooklyn)-Northwestern Suffolk- Northeastern Suffolk-Southwestern Suffolk-Southeastern Suffolk- Northern Queens-Northern Nassau-Southern Queens-Southern Nassau- 326 AM EDT Thu Aug 27 2020 This Hazardous Weather Outlook is for southern Connecticut, northeast New Jersey and southeast New York. .DAY ONE...Tonight. The Storm Prediction Center has placed the area in an enhanced risk for severe thunderstorms this afternoon into this evening. Severe thunderstorms are likely with damaging wind gusts of 60 mph or higher, along with large hail as the primary threats. An isolated tornado is also possible along with brief heavy rainfall. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Hazardous weather is not expected at this time that would meet NWS warning criteria. .SPOTTER INFORMATION STATEMENT... Spotter activation will likely be needed. Please safely report significant weather conditions while following local, state, and CDC guidelines. && 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. ANZ330-335-338-340-345-350-353-355-280730- Long Island Sound East of New Haven CT/Port Jefferson NY- 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- 326 AM EDT Thu Aug 27 2020 This Hazardous Weather Outlook is for Atlantic coastal waters. .DAY ONE...Tonight. The Storm Prediction Center has placed the area in an enhanced risk for severe thunderstorms this afternoon into this evening. Severe thunderstorms are likely with damaging wind gusts of 60 mph or higher, along with large hail as the primary threats. An isolated tornado is also possible along with brief heavy rainfall. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Hazardous weather is not expected at this time that would meet NWS warning criteria. .SPOTTER INFORMATION STATEMENT... Spotter activation will likely be needed. Please safely report significant weather conditions while following local, state, and CDC guidelines. && 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), 76 km away, was scanning. The volume nearest the first event began at 19:50 UTC.
16 thunderstorm wind, 1 tornado. Local standard time, as filed.
Large tree uprooted on Lounsbury Street.
Tree and branches down on a house.
EF1 Tornado staring in Bethany, CT and ending in North Haven, CT. Maximum path width of 500 yards and a path length of 11.1 miles.
Based on a National Weather Service damage survey done in |conjunction with CT Division of Emergency Management and Homeland |Security and local CT town emergency managements, it has been |determined that a strong EF1 tornado, with maximum wind speed of |110 mph, tracked southeast from Bethany to North Haven CT.
The tornado first touched down in a forested area to the |southeast of Judd Hill Rd in Bethany CT. The tornado tracked |southeast over primarily forested areas from Amity Rd, to Munson |Rd towards Litchfield Tpke, creating a path of damage about 75 |yards wide, with hardwood tree damage consistent with wind speeds |of 80 to 90 mph.
The path of damage widened to around 300 yards as the tornado |tracked southeast towards Lake Bethany. Structural damage, |including significant roof damage to several homes, and snapped |hardwood trees indicated wind speeds of around 100 mph in this |area.
The tornado path continued southeast for another 4 miles to near |the town center of Hamden CT, with tree and structural damage |indicative of wind speeds of 70 to 80 mph. The intensity picked up|significantly as the tornado approached the center of Hamden, as |evidenced by extensive damage to numerous buildings, including the|flat roof of a 2 story building across from Hamden Town Hall |being torn apart. Wind speeds are estimated to be around 100 mph |based on the damage to these buildings, bent metal fencing around|town hall, and uprooted and snapped trees.
The tornado reached maximum strength and width from this point on|as it continued southeast across Wilbur Cross Parkway, Interstate|91, and down to the intersection of Arrowdale and Thompson St in |North Haven, CT. Tremendous hardwood tree damage and structural |damage was indicative of wind speeds of 110 mph and an expanded |width of 500 yards. It is a this point that the tornado appears to|have dissipated with its destructive straight line winds fanning |out to the coast.
Video of a tree down blocking one lane on I-84.
Numerous large hardwoods uprooted on Virginia Road with time estimated from radar.
Video of multiple large trees reported down.
A thunderstorm wind gust of 69 mph was measured at downtown FW5820 New Haven mesonet.
Large tree fell on SUV on Old Quarry Road with time estimated from radar.
Numerous large trees and power lines down across Branford.
Tree tops twisted and power lines down on Featherbed Lane.
Trees reported down on Danbury Road.
Numerous trees and wires down across Westport.
Trees down and wires on car with people trapped on Wilton Road. One person attempted to exit and was shocked.
Power poles down on Old Hill Road with road closed.
Video shown of a large tree down on a house.
Trees reported down across Rocky Brook Road.
Trees reported down on Journey's End Road.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Connecticut in 2020Every state in 2020This day in weather historyThe tornado archive for Connecticut, 2020Warnings in Connecticut, August 2020
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: 921259, 921260, 921246, 921261, 921272, 921273, 921275, 921276, 921278, 921279, 921088, 921089, 921090, 921093, 921130, 921132, 921133.