A large upper level low pressure system in the jet stream will entrain itself over the eastern U.S. throughout the next few days and “cut off” from the flow aloft. What this will mean is persistent cloudy and damp weather here in the Ohio Valley.
Earlier in the week this area of low pressure was expected to situate itself just southeast of Tri-State leaving us in a cooler but dry area. Forecast models are now converging on the system parking itself ever so slightly more north meaning the moisture in place now will get stuck. At the surface, a stiff northeast wind will funnel in cooler air making the weather fairly nasty for the rest of the week. Winds may gust out of the northeast between 20 and 30 mph over the next few days.
Confidence in the fine details of the forecast (exactly when it will rain / how cool it stays each day) is still relatively low at this point especially going into the weekend. This is due to a large disparity in various model solutions and how they are handling the (potential) interaction between the upper low and (soon to be) Hurricane Joaquin. The American, Canadian, and several tropical models are starting to converge on a solution that would have a potentially strong system slamming into the Mid-Atlantic or Carolina coast this weekend. Meanwhile, the normally reliable European model and a few other members of various model packages are bent on taking the system out to sea. While our weather in Ohio will certainly not resemble a hurricane regardless, the outcome could have a large impact on our sensible weather here. A resultant track into the U.S. would significantly slow down the upper low giving us the clouds and rain for longer. It would also throw additional moisture back our direction from the Atlantic meaning even more rainfall this weekend. Due to the extremely complex nature of the setup and poor consistency among models, it is still too soon to say what impacts (if any) Joaquin could have on the U.S.
With all of that in mind…You can expect cloudy, cool, and occasionally showery weather through at least the end of this week. Temperatures today will be quite a bit cooler than the past few days as highs barely make the middle 60s. Drizzle and light showers are possible this morning but the bulk of the rain should stay east of Cincinnati today. Areas from Falmouth and to the east (including parts of Clermont/Brown/Adams counties) are more likely to see a few scattered showers through the day.
The chance for scattered showers will be in play for the entire Tri-State on Thursday although a better shot at rain appears to be in the cards on Friday. The rain is expected to be scattered in nature both days and not persistent all day. Highs both days could be held to the upper 50s thanks to the clouds.
The chance for rain will remain in the forecast on Saturday as the upper low over the area ever so slowly starts to move east. If the hurricane does take the west track into the East Coast, then a more widespread rainfall event would be likely here. At this point the forecast is leaning slightly in the direction of the guidance suggesting the storm hitting the coast, but as stated previously it is simply too soon to nail it down.
It does look like we dry out and warm up a little bit moving forward into next week.