Showers and storms developed with support from an upper level shortwave passing across the upper Ohio valley. Despite the provided lift, rather warm mid levels and early morning cloud cover were limiting factors that helped keep thunderstorms disorganized.
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The episode as NWS PBZ wrote it up.
Showers and storms developed with support from an upper level shortwave passing across the upper Ohio valley. Despite the provided lift, rather warm mid levels and early morning cloud cover were limiting factors that helped keep thunderstorms disorganized.
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 Pittsburgh, PA wrote its last area forecast discussion before the first event at Aug 17, 12:37 PM EST, 40 minutes earlier.
Area Forecast Discussion National Weather Service Pittsburgh PA 137 PM EDT Thu Aug 17 2017 .SYNOPSIS... Rain is likely with a cold front later today and into Friday. Temperatures will stay warm through the weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Still keeping an eye on two areas of rain. The first is across central/eastern Ohio with scattered showers, while the second remains with the cold front currently across eastern Indiana. The HRRR model continues to waver in its timing from run to run, but still think that the first round of precipitation will enter the area mid to late afternoon. Previous discussion below... The quasi-stationary boundary over Southern Ohio will be pushed northward as a warm front this morning, by a rather vigorous shortwave that will move across Northern Ohio, reaching Northwestern Pennsylvania by early this afternoon. This will eventually place the entire area well into the warm sector, and pump up humidity levels. With the late morning wave, models are keeping most of the activity to the north, closer to its path, while south of this, convection looks to be more scattered or isolated. There will be some limiting factors to storm development and intensity that will need to be closely watched today. The main one, at least through the afternoon, will be the very warm air aloft, which will provide a cap on the atmosphere. In addition, cloud cover associated with the morning wave, will work to limit sunshine, and readings may fall short of forecasted convective temperatures. If the cap is strong enough, cloud cover could decrease as the afternoon progresses. This will all need to be closely watched today. By late this afternoon and into the early evening, the aforementioned shortwave will be moving rapidly over North- Central Pennsylvania. Another, weaker shortwave trough, will move into my Ohio counties by early evening. Models are redeveloping convection ahead of this second wave, moving it eastward during the remainder of the evening hours. At this time, it appears the NAM is struggling with convective feedback, due to an over amplification of the omega field and by trying to develop a cool pool aloft with the wave, which does not seem to be realistic. Additionally, the NAM may be overdoing the PWAT values for today, but I do think, with dewpoints pushing toward or into the 70s, heavy downpours will be a concern. The good news is that the pattern will be progressive, with forecasted storm motion of 20 to 24kts, so individual cells should be moving quickly. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... Shortwave trough will be east of the area shortly after midnight. Once the large scale ascension moves east, and diurnal stabilization overtakes the atmosphere, expect the activity to not only move east, but also weaken. Will keep in the risk for showers/storms overnight, with the higher PoPs drifting eastward with the exiting wave. Lingering showers are possible Friday morning, although the coverage is questionable, as the best lift will be well to the northeast and well to the southwest of the region. It's likely that models are filling showers in through the entire trough axis, which would focus the activity over the southeastern quadrant of the area. As afternoon approaches, the trough axis will shift southeastward toward the Mid-Atlantic region, which should bring an end to the risk of showers, save for the far southeastern ridges. The cold front will finally begin to cross the area late Friday afternoon reaching Northern West Virgina by late evening. By this time, the best lift will be southeast of the area as will be the deep moisture. Because of this, have decided to leave FROPA dry, but this will likely need to be further investigated in future model runs. Cooler air will overspread the area Friday night and Saturday. A strong shortwave trough will cross the region late Saturday afternoon and evening. Have decided to go with slight to low chance PoPs with this feature, as there will likely be another surface boundary accompanying the upper level wave. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... Broad high pressure will build across the region for the end of the weekend into the beginning of the work week. A cold front should then bring a chance of rain back to the region for Tuesday and Wednesday. Temperatures will remain near average, building into the middle of next week. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... Warm front moving through the forecast area this afternoon is generating scattered showers and thunderstorms. These will continue to blossom through the evening, becoming more numerous and strengthening. Several rounds of showers and thunderstorms are then possible through early Friday, when a cold front finally pushes through. Temporary restrictions and gusty winds will be possible in any thunderstorm activity. After the passage of the front, some MVFR or high IFR stratus is possible centered around dawn Friday. Any stratus that does develop will gradually improve through the day. Light southerly flow will shift to west-southwesterly with occasional gusts Friday. .Outlook... Restrictions are possible with another passing disturbance Saturday. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...None. OH...None. PA...None. WV...None. &&
Hazardous Weather Outlook National Weather Service Pittsburgh PA 101 PM EDT Thu Aug 17 2017 OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>015-020>022-029- WVZ001>004-181200- Tuscarawas-Carroll-Columbiana-Coshocton-Harrison-Jefferson-Muskingum- Guernsey-Belmont-Noble-Monroe-Mercer-Venango-Forest-Lawrence-Butler- Clarion-Beaver-Allegheny-Armstrong-Washington-Hancock-Brooke-Ohio- Marshall- 101 PM EDT Thu Aug 17 2017 This Hazardous Weather Outlook is for east central Ohio, northwest Pennsylvania, southwest Pennsylvania, west central Pennsylvania, western Pennsylvania, northern West Virginia and northern panhandle of West Virginia. .DAY ONE...This Afternoon and Tonight. There is a slight risk of thunderstorms reaching severe levels this afternoon into the overnight. Damaging wind gusts are the primary threat. In addition, showers and storms may produce heavy downpours which could lead to localized flooding. .DAYS TWO THROUGH SEVEN...Friday through Wednesday. 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. MDZ001-PAZ016-023-031-073>076-WVZ012-021-509>514-181200- Garrett-Jefferson-Indiana-Greene-Westmoreland-Westmoreland Ridges- Fayette-Fayette Ridges-Wetzel-Marion-Monongalia- Ridges of Eastern Monongalia and Northwestern Preston-Preston- Eastern Preston-Western Tucker-Eastern Tucker- 101 PM EDT Thu Aug 17 2017 This Hazardous Weather Outlook is for western Maryland, southwest Pennsylvania, west central Pennsylvania and northern West Virginia. .DAY ONE...This Afternoon and Tonight. Showers and storms late today and overnight may produce heavy downpours which could lead to localized flooding. Isolated storms could reach severe levels with damaging wind gusts as the main threat. .DAYS TWO THROUGH SEVEN...Friday through Wednesday. 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.
The Pittsburgh radar (KPBZ), 75 km away, was scanning. The volume nearest the first event began at 18:17 UTC.
1 thunderstorm wind. Local standard time, as filed.
Emergency manager reported numerous trees uprooted and ripped off along Fresno Road, Fisherman Road, and Bacon Road.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Ohio in 2017Every state in 2017This day in weather historyWarnings in Ohio, 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: 719669.