Cut Off Low Lingers, Then Frosty

Thanks to a very slow moving cut off low clouds and rain have set up a home since late Thursday across much of Illinois, Indiana, and Ohio. While we did have periods of sunshine and pleasant temperatures, rain was always around in some areas. Late on Sunday a surface low with a cold front and associated occluded front slowly inched eastward bringing copious amounts of rain to southeastern Indiana and southwest Ohio. Monroe, Ohio received over 6 inches of rain in just over 12 hours. Cincinnati and Dayton both received well over 3″ of rain at their official stations with several areas in between coming in with between 4 and 5 inches of rain. The heavy nature of the rain in conjunction with the crawling front and Gulf of Mexico moisture fetch brought record rainfall amounts for September 26 at the Cincinnati-Northern Kentucky Airport and the Dayton Cox International Airport. In fact, the 3.52″ of rain that fell in Dayton made this is the wettest September on record and leaped this month to the third wettest month ever. As the theme has been for the last few weeks, unusual weather continues across the Ohio Valley. To top it all off, some sunshine greeted the area by mid to late afternoon. So this is it for the rain, right?

Actually, no it is not. How about the chance of rain for the next four days. While nothing is expected like Monday’s deluge, scattered showers and thundershowers will linger because the cut off low that has been influencing our weather for the last five days is still over Illinois. It is going to take until early Friday morning when another surface cold front can actually kick this whole pattern to the east before the chances of rain subside. At the early hours of Tuesday morning rain is already moving back into central Indiana, whereas places in Ohio should remain dry through mid day. Another indication of just how slow this cut off low is moving. By Tuesday afternoon rain will spread back across the western half of Ohio and by Tuesday evening across the central part of the Buckeye State. If you want to talk more milestones, if Dayton can pick up another 0.63″ it will move into second place all time on the monthly rainfall record surpassing June of 1958, leaving only January of 1937 as a wetter month than this month.
Cut Off Low Begins to Weaken by Thursday over Northern Ohio; Courtesy of NCEP

For Wednesday and Thursday, the cut off low begin to weaken as it positions itself over northern Ohio. At the same time, the next trough and associated front, as mentioned prior, will begin to sweep down into the Plains, as seen above in the map. The combination of front and trough will push this system out and finally dry the region out by early Friday morning in the West and by late Friday afternoon in the East. The good news is that a dry and mostly sunny weekend is on tap, the bad news is very chilly temperatures will greet you in the morning. For months you have heard abut a realistic shot of frost for September and while that has indeed happened in some outlying areas or sheltered spots, this shot should be a more widespread shot. While no killing freeze is anticipated, sensitive or warmer climate vegetation should be protected or brought inside to survive the cold temperatures.

Forecast Highs For Saturday in the Low to Middle 50s for Most; Courtesy of pro.accuweather.com

Also, if you have early morning activities on Saturday or church services on Sunday be prepared to break out the ice scrapers for the first time since early May. Temperatures over the region for the weekend should hold mainly in the low to mid 50s on Saturday and upper 50s to low 60s on Sunday so after the cool starts, seasonably cool afternoons are expected.

The dry weather should last into most of next week, so a solid 5 to 7 days of dry weather will kick off October weather in fine fashion. Partly to mostly sunny skies and temperatures mainly in the 70s will greet the region. This relatively mild stretch should continue into the following week but signs of stronger and colder weather are already showing up by the middle of October. That is a matter to discuss at a later time but for the next few days, more showers and possible thunderstorms will be the main topic of focus in the weather department but patience will lead to a sunny weekend to kick off the 10th month of the year.

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By Weather Specialist Josh Ketchen