A cold front moves across the northeast Pennsylvania Friday afternoon, and showers and thunderstorms developed ahead and along the front. As the front moved it, it moved into an unstable environment.
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 BGM wrote it up.
A cold front moves across the northeast Pennsylvania Friday afternoon, and showers and thunderstorms developed ahead and along the front. As the front moved it, it moved into an unstable environment. Some of these storms became severe and produced damaging winds.
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 Aug 18, 11:34 AM EST, 1 hour 5 minutes earlier.
Area Forecast Discussion National Weather Service Binghamton NY 1234 PM EDT Fri Aug 18 2017 .SYNOPSIS... A few showers or thunderstorms, could linger into this evening, as a cold front passes through the region. Saturday and Sunday look mostly rain-free, with seasonable temperatures, thanks to high pressure, building down from eastern Canada. && .NEAR TERM /THROUGH SATURDAY/... A very moist atmosphere covers northeast Pa and much of central NY late this morning with dew points ranging from the upper 60s to the mid 70s. Latest SPC meso-analysis showing an axis of 2.0 inch precipitable water values extending northeast across northeast Pa, with values falling off to around 1.2 inches over far western NY. The 12z BUF sounding shows a much dryer atmosphere over western NY with some capping advancing slowly eastward toward central NY. A mid-to-upper level trough is advancing east from the Great Lakes but the bulk of this system is forecast to lift north of our area this afternoon with minimal height falls across our area. Persistent but broken band of showers from central Pa northeast toward the Catskills is forecast to push slowly east through this afternoon with highest rain chances for our area over northeast Pa into Sullivan county NY. A little clearing can be seen over southern Pa and this may work into northeast Pa this afternoon which would enhance the convective potential. MLCAPE values would likely climb to near or just above 1000 J/kg with any clearing in that area, and with mid-level flow forecast around 40 kts the shear/cape combination will be enough for a slight risk of severe weather with rotating storms a possibility. Again this is dependent on getting some clearing and instability. Localized heavy rain will also be a concern with very moist profiles. Farther northwest some clearing is likely this afternoon from the Finger Lakes to Mohawk valley but the very dry airmass moving in from western NY should act to inhibit convective chances. Expecting scattered showers and storms to develop after 2 pm but the severe risk for upstate NY looks rather low. Previous forecast is below. Water vapor channels on the GOES-16 show deep moisture advecting northeast into NY and PA in advance of a well defined upper level wave in the Upper Great Lakes region. Also in advance of this wave was a strong low-level jet seen in the VWP winds around 1 KM above ground level of at least 40 knots from the southwest. Model guidance was picking up on this belt of low-level winds which were rising isentropically and advecting moisture into the local area. This also was destabilizing the atmosphere and leading to convection which was moving across central NY and northeast PA at this time. This first batch of showers and isolated storms was well handled by the latest HRRR run. There was also another batch of showers in southwest PA that the HRRR brings northeast into northeast PA and parts of central NY between 10z and 17z. So weighted POPs based on HRRR reflectivity fields. Then after 17z, Models show the layer of deeper moisture tracking quickly east of central NY and by 00z southeast of northeast PA. Best chance for additional showers and storms will be in this deep moist layer in northeast PA/Sullivan Co. NY where precipitable waters were around 2.00 inches. The forcing for ascent in this moist layer was not that impressive but enough for activity to form. For now, have added chance for locally heavy rain in northeast PA-Sullivan NY. Concur with marginal risk for flash flooding from the WPC outlook. Will update Hazardous Weather Outlook and mention enhance wording for the chances of flooding in these areas. The rest of the forecast area this afternoon will be under very dry layer aloft as seen in the low-mid and high level water vapor channels and without sufficient forcing initially, parcels will just entrain out despite large projected mixed layer CAPES. Some isolated to scattered showers and marginal storms could form but best chance for any organized storm activity will come around 22z-02z or so when a cold front presses east with the advancing upper level wave from the Great Lakes. But, at this time CAPEs will be dropping. Shear values were fairly impressive with the 0-6 km values around 35-40 knots. NAM 3KM does have a line of storms forming around 00z or so. So we will continue to mention chance for severe thunderstorms in HWO and concur with SPC marginal risk for severe. For later tonight, convection passes east and some lingering showers remain. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... 1230 pm update... Overall, things will be quieting down this period, as the flow aloft flattens out, and surface ridging builds into NY/PA from the west. Any lingering early evening showers Saturday should quickly dissipate with time. Thereafter, rain-free weather is expected, with skies becoming mostly clear for the second part of the weekend. Temperatures will be seasonable, with Sunday's highs mostly in the upper 70s-lower 80s, along with low humidity levels. && .LONG TERM /MONDAY THROUGH THURSDAY/... 1245 pm update... On the large-scale, model agreement is fairly good this period, indicating a transition towards more amplification once again next week. This pattern should take the form of a western Canadian-northwest CONUS trough, central CONUS-intermountain west ridge, and an eastern Canadian- northeast CONUS trough. The week should start out generally rain-free and warm from Monday through much of Tuesday, with highs mostly in the 80s. As heights aloft begin to fall ahead of the developing eastern trough mentioned above, a cold front should slowly approach, and bring increasing chances of showers/thunderstorms from later Tuesday into Wednesday. Later next week, although we should trend drier behind the aforementioned cold front, it likely turn much cooler as well. In fact, by next Thursday/Friday, we're looking at highs in the upper 60s-lower 70s for many areas of CNY/NEPA. && .AVIATION /16Z FRIDAY THROUGH TUESDAY/... Flight conditions highly variable this morning as showers move periodically through the forecast area. Ceilings bouncing all over the place, but for the most part it will remain VFR-MVFR across the north half, while general MVFR dominates in southern areas. Main wave train of upper waves driving these conditions exits east by midday with drier air expected later today and tonight for generally VFR. Renewed convective activity this afternoon/evening may affect mostly KAVP with several rounds/hours of thunderstorms and poor flight conditions. Drier air works in tonight, clearing out the deep moisture and low ceilings...however, with ground based moisture, flight restrictions in fog and low ceilings may develop after 06Z. Winds becoming southwest around 10 kts by midday, followed by more westerly directions late this afternoon, then light and variable tonight. Outlook... Friday overnight...VFR. Saturday...VFR. Chance of flight impacts in afternoon showers. Sunday through Monday...VFR. Tuesday...Flight impacts possible in thunderstorms. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...None. && SYNOPSIS...MLJ NEAR TERM...DJN/MSE SHORT TERM...MLJ LONG TERM...MLJ AVIATION...JAB
Hazardous Weather Outlook National Weather Service Binghamton NY 435 AM EDT Fri Aug 18 2017 NYZ009-015>018-022>025-036-037-044>046-055>057-PAZ038-039-190845- Northern Oneida-Yates-Seneca-Southern Cayuga-Onondaga-Steuben- Schuyler-Chemung-Tompkins-Madison-Southern Oneida-Cortland-Chenango- Otsego-Tioga-Broome-Delaware-Bradford-Susquehanna- 435 AM EDT Fri Aug 18 2017 This Hazardous Weather Outlook is for central New York and northeast Pennsylvania. .DAY ONE...Today and Tonight. Isolated to scattered showers and a few thunderstorms will continue on and off into the afternoon. There is a chance for a line of thunderstorms late this afternoon into this evening which could cause gusty winds and hail. .DAYS TWO THROUGH SEVEN...Saturday through Thursday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed this afternoon and evening. NYZ062-PAZ040-043-044-047-048-072-190845- Sullivan-Northern Wayne-Wyoming-Lackawanna-Luzerne-Pike- Southern Wayne- 435 AM EDT Fri Aug 18 2017 This Hazardous Weather Outlook is for central New York and northeast Pennsylvania. .DAY ONE...Today and Tonight. Isolated to scattered showers and a few thunderstorms will continue on and off into the afternoon. Thunderstorms will become more numerous this afternoon into the evening. Some of the thunderstorms could produce excessive rain and potentially cause some flood problems. Additionally, there is a chance for thunderstorms to produce locally strong wind gusts. .DAYS TWO THROUGH SEVEN...Saturday through Thursday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed this afternoon and evening. DJN
The Binghamton radar (KBGM), 65 km away, was scanning. The volume nearest the first event began at 17:39 UTC.
1 thunderstorm wind. Local standard time, as filed.
A thunderstorm moved across the region and became severe. This thunderstorm produced severe winds and produced structural damage to a house.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2017Every state in 2017This day in weather historyWarnings in Pennsylvania, August 2017
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: 712295.