Historic August Rainfall/Severe Weather Recap

The clean up continues after the second round of heavy rain/severe storms across northern Ohio.

17 school districts closed due to damage and power outages:

Here is the COMPLETE radar loop from August 23 at noon through early August 25 before sunrise. Warnings, watches and lightning are included for northern Ohio.

I separated the 2 day rain event into 3 separate radar loops starting at 9pm August 24 through August 25 at 3am:

August 23 - 12:30PM through August 24 - 5AM

August 24 - 5AM through August 24 9AM

August - 9PM through August 25 - 5AM

Historic rainfall over 48 hours with two separate large clusters of rain/storms:

Another vantage point shows the heaviest rain from southern Michigan through Ohio and western PA.

Since August 1, most of northern Ohio has received 200-400% of normal rainfall:

Severe storm warnings were widespread. Most of northern Ohio was under a severe thunderstorm warning at some point between August 23 and early August 25.

4 tornado warnings. 12 tornadoes. COMPLETE NWS RECAP

The EF-1 that occurred on the east side of Cleveland was the first tornado that occurred within the Cleveland city limits since July 12, 1992 per NWS Cleveland. That tornado occurred near Hopkins Airport.

Here are ALL of the tornadoes from 1950 to 2022 in Cuyahoga County

Why did this heavy rain occur?  What were the factors that lead to this?

The huge ridge of heat in the central US has been a fixture for at least a week. 

Where high pressure resides, low pressure has to follow either down or up stream. Disturbances rode up and over the ridge and down through the Great Lakes.  

Great lakes radar loop from Wednesday through Friday: The excessive heat watches/warnings are shown in red.

Couple this with the high humidity (dewpoints above 75) and you have the recipe for heavy rainfall.

Interestingly, the historic Derecho in 1969 on the 4th of July produced MORE rainfall!

Here are the final rainfall numbers between August 23-25 using the same perspective as the 1969 map above (for comparison)

Oh and almost 75,000 lightning strokes over the 48 hour period across Ohio!

Flood Warnings Through June 25th

Issuance numbers for each NWS forecast office from January 1 through June 25 each of the last 10 years. Note that the colorized legend changes for each year depending on the range.

Which weather service office leads the pack this year?  NWS Indianapolis with 343. The most of any office through June 25th since 2010

NWS Cleveland Flood Warning count

Updated Rainfall vs Normal

Rainfall vs normal last 60 days across Ohio Valley and Midwest

Rainfall vs normal last 14 days

Ohio Valley rainfall last 72 hours (June 15 morning thru June 18 morning)

Updated rainfall numbers at NWS Cleveland (Hopkins Airport)

Record Setting June Rainfall

The persistent pattern featuring frequent rain across the Ohio Valley ramped up into high gear the second half of June. Most points from Columbia, Missouri east into the Mid Atlantic states received between 100 and 400% MORE rainfall than normal this last month.

Parts of northern Ohio had between 10 and 15 inches as a stalled front oscillated back and forth triggering clusters of rain and storms. Cleveland's monthly total was 3rd most in 145 years, most since 1972.  Ft Wayne, Indiana set their all-time June rainfall record with 11.98". It broke the record for the wettest month set in July of 1986! 

Last summer's wet region was centered in the heart of the corn belt.

This summer's wet areas have shifted east into the Ohio Valley including Pennsylvania, Maryland and portions of New Jersey.

 

Compare the past two summer to the very warm summer of 2012. Dry conditions prevailed with the development of a flash drought across parts of the US. I gave a talk at the Ohio State Weather Symposium on the causes and the conditions that feed that summer's dry pattern.

My POWER POINT from the symposium is here. Check it out.

The average temperatures for July and August in 2012 were certainly influenced by the lack of rainfall. Notice the location of the temperature anomalies.

Temperature anomalies in 2014 were noticeably cooler over the wetter ground in the Corn Belt.

I emphasize that the rainfall or lack thereof was not the primary driver of the patterns in either 2012 or 2014.  It was an enhancer. June temperatures were at or slightly below normal.

Record high temperatures across the Midwest were markedly lower in 2014 vs 2012.

Big question, how will the June rainfall in the Ohio Valley influence the temperatures in the upcoming weeks?

More than likely, we should see a dampening of long stretches of heat in the mid-west, corn belt and Ohio Valley.  July could end up with temperatures at or below average from St. Louis to Cleveland.

Heavy Rain Update: Flash Flood Potential VERY HIGH

The ground is saturated from Monday's rain. An additional 1-3" of rain a very good possibility over the next 18 hours. Flash Flooding is the greatest concern. FLASH FLOOD WATCH FOR ALL OF NORTHERN OHIO UNTIL 10PM THIS EVENING. THIS MIGHT BE EXTENDED.

CURRENT RADAR LOOPS AND CURRENT OHIO TEMPERATURES




OHIO TEMPERATURES


OHIO VALLEY RADAR LOOP



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