Scattered showers and thunderstorms developed during the afternoon hours ahead of an approaching upper level disturbance.
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The episode as NWS ILN wrote it up.
Scattered showers and thunderstorms developed during the afternoon hours ahead of an approaching upper level disturbance.
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 Wilmington, OH wrote its last area forecast discussion before the first event at Jul 11, 9:01 AM EST, 2 hours 29 minutes earlier.
AREA FORECAST DISCUSSION National Weather Service Wilmington OH 1001 AM EDT Sun Jul 11 2021 .SYNOPSIS... Low pressure over Illinois with a warm front extending east into central Ohio will drift slowly northeast today, allowing humid and unstable air into the Ohio Valley where numerous showers and a few thunderstorms are expected. The low pressure and warm front will move very little tonight into Monday, keeping unsettled weather over the area, before slowly drifting east and dissipating by midweek. A new cold front will develop and approach the Ohio Valley by Thursday, maintaining the daily threats for showers and thunderstorms. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Moisture continuing to stream north across the area this morning, with an axis of showers and perhaps an embedded thunderstorm stretching northeast along the I-71 corridor. Morning ILN sounding had a pwat of 1.82 inches with a freezing level up around 13.2k feet. This is resulting in some fairly efficient rainfall rates/reduced visibilities. This axis will continue to shift off to the northeast through early afternoon. A fair amount of cloudiness across the area is once again impacting morning temperatures with readings still only in the upper 60s to lower 70s in many places and will make some minor downward tweaks to temps. There is some uncertainty as to how much clearing we will achieve heading into this afternoon as as a result, how well we will be able to destabilize. Additional short wave energy is forecast to move through the region through this afternoon so if we are able to destabilize enough, some additional redevelopment will be possible. Southwest flow of 25 to 30 knots in the 850-700 mb would likely be enough to support a few strong to severe storms if we do destabilize. The best chance for this would appear to be across our east/southeast where the better instability should reside later this afternoon. There is also some lower level directional shear into mid afternoon which may allow for a few rotating storms. The best chance for this looks to be across far northeast portions of our fa. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... Given the diurnal enhancement to the afternoon activity and the passing of shortwave energy off to the northeast by the evening hours, do expect some measure of decreased shower activity overnight, though not likely completely going away. Maintenance of the belt of 30kts of southwesterly mid level flow with cyclonic curvature, and the nearby upper low to the west ejecting MCVs and weak shortwave troughs, there's likely to be enough weak forcing given the very moist airmass to keep showers and a few rumbles of thunder in the forecast for much of the night, but there will be considerably less coverage especially after midnight. Destabilization via insolation on Monday morning and the persistence of ingredients already mentioned above means Monday will likely see another round of scattered showers and storms, increasing by late morning and peaking in the mid-late afternoon. As with Sunday, enough deep layer southwesterly flow and instability for water loaded downdrafts to potentially cause gusty/isolated damaging winds with the strongest cores or multicell line segments. Coverage should be pretty decent during peak heating so running 60-75% rain chances with highs in the lower 80s. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... On Monday evening, a closed upper low centered near the Quad Cities will be weakening and opening up into a wave, as the blocky pattern over the eastern half of the CONUS begins to get a little more progressive. Surface low pressure will also be weakening as it moves northeast from the same region into the Great Lakes, with the ILN CWA remaining comfortably in the warm sector through the evolution of this system. After a diurnal minimum on Monday night, chances for showers and storms will increase again rather significantly on Tuesday. The peak of the diurnal cycle should roughly coincide with the approach of the dampening upper trough, which will still provide a source of lift despite its weakening trend. In addition, decreasing temperatures at 700mb will aid in instability. Likely PoPs are in the forecast, peaking out during the mid to late afternoon. With unimpressive shear and lapse rates, overall storm intensity and organization will not likely be significant. Nonetheless, there may be enough for some isolated strong/severe convection and/or heavy rain, with precipitable water values over 1.75" and SBCAPE values approaching 2000 J/kg. Clouds and developing precipitation will likely keep temperatures in the lower to mid 80s. As the wave moves out of the area Tuesday night, Wednesday appears to be the day of the week with the lowest precipitation chances, as the ILN CWA will be in a region of the overall flow pattern that is not particularly favorable for ascent. With that said, some very disorganized pop-up convection still appears possible for Wednesday, before the min of the diurnal cycle allow for dry to mostly dry conditions Wednesday night. This weakness in the pattern will already be changing again by Thursday and into Friday, as broad troughing moves into the Great Lakes, and moisture advection / convergence increase from the middle Mississippi Valley through northwest Ohio. Still plenty of model disagreement on where exactly the frontal zone will set up, and if strong ascent will be in the ILN CWA or just off to the north and west. For now, will bring PoPs into the 50-70 percent range for Friday, then cap things at 50 percent through the weekend as uncertainty is greater. Thursday and Friday appear likely to be the warmest days of the week, as the ILN forecast area will be firmly in the warm sector, with only diurnal convective development as a possible mechanism for keeping temperatures down. For these two days, highs in the mid to upper 80s are expected, with an off-chance of some lower 90s. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/... First wave of rain has exited the ILN forecast area into northern Ohio and now second axis of rain is spreading back into CVG/LUK terminals. This will spread northeast through the morning toward ILN/CMH/LCK by mid morning, likely weakening a little further as it does so. Have prevailing showers for a few hours this morning with very little restriction to visibilities. There are some pockets of MVFR ceilings but conditions have been lifting a little behind the surface warm front which is just about ready to pass through the Columbus area terminals. A little later this morning into this afternoon, expect to begin to see some enhancement or development in vicinity of this current rainfall axis along/east of I-71 which is where the greatest coverage will be. Further west toward DAY, activity will be much more scattered. Any showers/storms later this morning into this afternoon will contain MVFR visibilities in heavy rain as well as MVFR ceilings, with the potential for IFR conditions in the heaviest activity. Should see coverage start to decrease this evening. Some signals that stratus may redevelop overnight with MVFR ceilings and visibilities in light fog. This is very low confidence right now. Mostly south- southwest surface winds < 10 knots today areawide, decreasing tonight. Locally strong gusts in the strongest showers and storms this afternoon. .OUTLOOK...Thunderstorms possible through Thursday. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && SYNOPSIS...Binau NEAR TERM...JGL SHORT TERM...Binau LONG TERM...Hatzos AVIATION...Binau
Hazardous Weather Outlook...CORRECTED National Weather Service Wilmington OH 419 AM EDT Sun Jul 11 2021 INZ050-058-059-066-073>075-080-KYZ089>100-OHZ026-034-035-042>046- 051>056-060>065-070>074-077>082-088-120830- Wayne-Fayette IN-Union IN-Franklin IN-Ripley-Dearborn-Ohio- Switzerland-Carroll-Gallatin-Boone-Kenton-Campbell-Owen-Grant- Pendleton-Bracken-Robertson-Mason-Lewis-Hardin-Mercer-Auglaize-Darke- Shelby-Logan-Union OH-Delaware-Miami-Champaign-Clark-Madison- Franklin OH-Licking-Preble-Montgomery-Greene-Fayette OH-Pickaway- Fairfield-Butler-Warren-Clinton-Ross-Hocking-Hamilton-Clermont-Brown- Highland-Adams-Pike-Scioto- 419 AM EDT Sun Jul 11 2021 This Hazardous Weather Outlook is for East Central Indiana, Southeast Indiana, Northeast Kentucky, Northern Kentucky, Central Ohio, South Central Ohio, Southwest Ohio and West Central Ohio. .DAY ONE...Today and tonight. Showers and thunderstorms today have the potential to produce brief heavy rain and minor flooding, especially in areas where storms move over the same area in repeated fashion. In addition, from late morning into early evening, a few storms will have the potential to become strong or severe, with the primary threat being gusty winds causing localized tree damage. .DAYS TWO THROUGH SEVEN...Monday through Saturday. More showers and storms expected Monday and Tuesday will again have the potential to produce localized flooding. Each of these days a few of these storms could be strong to severe with the primary threat being strong gusty winds. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
The national radar mosaic for the moment the first event began.
1 flood. Local standard time, as filed.
Several inches of water was flowing over County Road 605 near U.S. Route 36.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Ohio in 2021Every state in 2021This day in weather historyWarnings in Ohio, 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: 959441.