A warm front lifting across Northeast Pennsylvania and Central New York was the focus for several rounds of thunderstorm activity within a very warm and humid airmass. Slow moving, heavy rain producing thunderstorms contributed to several areas of minor flooding, along with, more serious flash flooding.
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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 BGM wrote it up.
A warm front lifting across Northeast Pennsylvania and Central New York was the focus for several rounds of thunderstorm activity within a very warm and humid airmass. Slow moving, heavy rain producing thunderstorms contributed to several areas of minor flooding, along with, more serious flash flooding.
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 Binghamton, NY wrote its last area forecast discussion before the first event at Sep 21, 6:51 PM EST, 2 hours 9 minutes earlier.
Area Forecast Discussion National Weather Service Binghamton NY 751 PM EDT Fri Sep 21 2018 .SYNOPSIS... A pronounced cold front will cross the area tonight, with showers and a few thunderstorms, along and ahead of it. Some of the storms could produce strong winds. Over the weekend and into early next week, Canadian high pressure will bring dry and cooler weather. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... 700 PM Update...Squall line approaching our western zones as of 7pm this evening. This line has a history of producing wind gusts mainly between 40-50 mph across western NY...with a few storms also showing signs of rotation. This line of thunderstorms should progressively move off to the southeast through the late evening hours across our forecast area. The best parameters to support any severe weather are in place across our western counties (Steuben, Schuyler, Yates, Seneca, Cayuga and Onondaga) where a severe thunderstorm watch remains in effect until 11 PM. Further south and east toward Binghamton, Norwich and Towanda, the line should move through around 10-11pm producing some lightning, gusty winds and brief downpours. The line of storms should gradually weaken as it heads east from here, reaching Monticello, Scranton and Wilkes-Barre around or just after midnight. Near term forecast update is out, and main adjustments were to the timing of the highest PoPs and also to increase southerly winds out ahead of the front early this evening ...especially across the northern Finger Lakes and Susquehanna region. In this area downsloping wind gusts have been up to 40-45 mph early this evening. 145 pm update... Steady as she goes with the current forecast. The latest runs of the convection allowing models still suggest a healthy squall line into our far northern/western zones, from about 23-00z. Thereafter, the line will weaken with eastward extent, as it crosses the rest of CNY/NEPA during the course of the evening. Further details for the rest of the afternoon into the evening hours are contained in the previous discussion. 1130 am update... The current forecast is in pretty good shape. Just cosmetic changes to the sky cover/POP/weather grids, based on the latest satellite, radar, and high resolution model data. Low stratus deck is holding stubbornly over much of the forecast area at midday, as expected. Although some erosion at the western fringes is possible this afternoon, for the most part, things should remain as they are, with partly sunny skies and warm temperatures in our far northern/western zones, and cloudy, much cooler conditions elsewhere. Just subtle changes to our high temperature grid were made, with maximum temperatures near 80 where sunshine prevails in the western Finger Lakes/Lake Ontario plain areas, and only reaching the 60s to lower 70s for the remainder of CNY/NEPA. The latest convection allowing models are in very good agreement, showing a well developed squall line moving into our far northern/western zones towards 7-8 pm, with just isolated activity earlier. As expected, a sharp stability gradient exists, with ML CAPE perhaps into the 500-1000 j/kg range by later this afternoon where the clouds break, with almost no destabilization where the clouds hold. Wind fields (especially in the lower levels) are quite impressive, so any earlier discrete cells would have to be closely watched, along with obviously the linear feature itself into the early evening. We still think convective intensity will quickly wane with eastward extent after about 8-10 pm, with only a few lingering showers surviving after midnight. Please check our latest hazardous weather briefing online for more specific details on possible severe weather development/timing. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... 340 PM Update... Saturday and Saturday night: Northwest flow will continue through much of the day Saturday behind the departing cold front. Will see some upslope/lake enhance clouds through the morning and early afternoon hours...with perhaps an isolated shower as well. Otherwise it will be much cooler with NNW winds 10-15 mph in the morning, decreasing to less than 10 mph by afternoon. High temperatures only reach the upper 50s to mid- 60s. Surface high builds overhead Saturday night with strengthening low level inversion, light winds, river valley fog and very cool temperatures. Low temperatures are forecast to be in the upper 30s to 40s areawide. Sunday and Sunday night: Early morning fog burns off giving way to mostly sunny skies with continued light northerly winds. Slightly warmer with highs in the mid to upper 60s. Strong Canadian high to the north for Sunday night, with a northeast drainage flow over our area. Another strong low level inversion night, with mostly clear skies and patchy fog possible again. Remaining chilly with lows in the 40s. Monday: Upper level ridge builds over the area from the Mid-Atlantic as the surface high slowly exits off to the northeast. Still have a dry easterly flow, especially in the low to mid-levels of the atmosphere. With large dew point depressions suspect it will take quite a while for any rain showers to move in from the south. Therefore, expect just gradually increasing clouds, with cirrus lowering and thickening from south to north through the afternoon hours. Slight chance of a late day shower across southern Luzerne/Bradford counties. Southeast winds increasing, 8-15 mph by afternoon. High temperatures reach mid to upper 60s once again. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... 340 PM Update... A wave with a quasi warm frontal boundary approaches the area from the south Monday night...PoPs quickly increase from SW to NE as the atmosphere moistens up. Introduced likely PoPs for much of the area after 06z Tuesday...with early rainfall forecasts between a quarter to half inch possible by Tuesday morning. It remains unsettled on Tuesday with our CWA getting into the warm sector of a low pressure system passing by well to the north. It should be mostly cloudy with scattered showers around, and perhaps enough instability for an afternoon t'storm. The cold front slowly approaches from the west Tuesday night into Wednesday. This will keep showers in the forecast, with a chance of thunderstorms during the day Wednesday. There are some model discrepancies for Thursday, as the latest 12z GFS now attempts to stall the frontal boundary over Central NY and Northeast PA leading to additional showers. Meanwhile most of the other guidance sweeps the front through the area with drier air moving in. For now, used a blend of the guidance which gives a chance for a few showers. Early indications are that yet another frontal system could approach the area toward next Friday, therefore kept chances for showers in the forecast. Temperatures through the long term period will be mainly in the 60s to lower 70s during the day...with overnight lows in the 50s. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... Low clouds continue at KITH, KELM, KBGM and KAVP with mainly fuel alternate and/or IFR cigs. A line of thunderstorms will move across the region region this evening with gusty winds, lightning and very brief heavy rain possible. Ceilings will likely lift a category and then possibly drop back down later tonight before returning to VFR after 14-15Z Saturday morning. Gusty south winds will shift to the w/nw behind the front and eventually bring in much drier air and VFR conditions during the afternoon hours on Saturday. Outlook... Saturday night through Monday...Mainly VFR. Tuesday and Wednesday...Possible restrictions in showers. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...None. && SYNOPSIS...MLJ/MJM NEAR TERM...MLJ SHORT TERM...MJM LONG TERM...MJM AVIATION...BJT/MLJ
Hazardous Weather Outlook National Weather Service Binghamton NY 410 PM EDT Fri Sep 21 2018 NYZ009-015>018-022>025-036-037-044-055-PAZ038-222015- Northern Oneida-Yates-Seneca-Southern Cayuga-Onondaga-Steuben- Schuyler-Chemung-Tompkins-Madison-Southern Oneida-Cortland-Tioga- Bradford- 410 PM EDT Fri Sep 21 2018 This Hazardous Weather Outlook is for central New York and northeast Pennsylvania. .DAY ONE...Tonight. This evening a strong cold front will cross the area with showers and thunderstorms. Some of the thunderstorms could have damaging wind gusts and brief heavy rain. .DAYS TWO THROUGH SEVEN...Saturday through Thursday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to Standard Operating Procedures. NYZ045-046-056-057-062-PAZ039-040-043-044-047-048-072-222015- Chenango-Otsego-Broome-Delaware-Sullivan-Susquehanna-Northern Wayne- Wyoming-Lackawanna-Luzerne-Pike-Southern Wayne- 410 PM EDT Fri Sep 21 2018 This Hazardous Weather Outlook is for central New York and northeast Pennsylvania. .DAY ONE...Tonight. This evening a strong cold front will cross the area with showers and isolated thunderstorms. Some of the thunderstorms could have gusty winds and brief heavy rain. .DAYS TWO THROUGH SEVEN...Saturday through Thursday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to Standard Operating Procedures.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BINGHAMTON NY
918 PM EDT FRI SEP 21 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0908 PM FLASH FLOOD WOODHULL 42.08N 77.42W
09/21/2018 STEUBEN NY 911 CALL CENTER
WATER ACROSS ROAD CTY RT 101
&&
HLCPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BINGHAMTON NY
920 PM EDT FRI SEP 21 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0917 PM FLASH FLOOD ADDISON 42.11N 77.23W
09/21/2018 STEUBEN NY 911 CALL CENTER
WATER IN THE BASEMENT OF HOUSE.
&&
BJTPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BINGHAMTON NY
922 PM EDT FRI SEP 21 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0920 PM FLASH FLOOD 3 NW LINDLEY 42.06N 77.17W
09/21/2018 STEUBEN NY 911 CALL CENTER
REPORTS OF WATER OVER THE ROAD AND A TREE DOWN BLOCKING
THE ROAD.
&&
BJTPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BINGHAMTON NY
937 PM EDT FRI SEP 21 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0934 PM FLASH FLOOD 6 WSW LINDLEY 42.00N 77.24W
09/21/2018 STEUBEN NY 911 CALL CENTER
TWO ELDERLY PEOPLE TRAPPED IN A HOUSE.
&&
BJTPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BINGHAMTON NY
939 PM EDT FRI SEP 21 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0917 PM FLASH FLOOD 4 SE WOODHULL 42.04N 77.36W
09/21/2018 STEUBEN NY 911 CALL CENTER
WATER RESCUE REQUESTED FOR 6 PEOPLE TRAPPED IN A
TRAILER.
&&
BJTPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BINGHAMTON NY
1000 PM EDT FRI SEP 21 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0958 PM FLASH FLOOD WEST ELMIRA 42.09N 76.85W
09/21/2018 CHEMUNG NY 911 CALL CENTER
ROAD FLOODED WEST CHURCH AND COLEMAN
&&
HLCThe Binghamton radar (KBGM), 79 km away, was scanning. The volume nearest the first event began at 01:59 UTC.
1 flash flood. Local standard time, as filed.
Flash flooding deposited rocks and mud over the road, blocking traffic for over an hour.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2018Every state in 2018This day in weather historyWarnings in Pennsylvania, September 2018
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: 786869.