Why Was It So Dry and Warm? Part III

The answer has many elements. We'll work from the more direct and near-by causes to the antecedent ones.

The pattern across North America was dominated by a "Rex Block" named after Meteorologist Daniel Rex in 1950 who discovered it. You can read about it HERE.

The configuration resembles a backward "S" with high pressure north of low pressure.  These are more common in the western US then over the Great Lakes. The result was a dominant easterly/SE flow which kept the temperatures well above normal not only across Ohio but much of the Great Lakes and Midwest with little rainfall. READ PART I HERE and  READ PART II HERE

Why did this Rex Block form?  I believe the answer lies first in the changing Equatorial Pacific. We have been teetering with a La Nina since last winter/spring.  Most of the summer has been in neutral territory. In the last month, the upwelling of cooler water to the surface is lowing sea surface temperatures especially west.

The pressure changes between Darwin station and Tahiti have been quick.

SOI changes have gone from positive to negative in recent weeks.

Further north in the higher latitudes, the North Atlantic Oscillation also went through changes at roughly the same time. Notice how the jet stream across North America and Europe was strong. Follow the black line across the US, northern Atlantic and Europe.

HUGE low pressure north of the Arctic circle and northern Atlantic with high pressure over Canada and eastern Europe.

As the NAO went negative, the jet stream shifted into southern US and Mexico and east into northern Africa. Little jet stream influence across Canada and the northern Atlantic.

HUGE high pressure ridge developed in eastern Canada north into the Arctic. This extended into the northern Atlantic and into northern Europe.

These changes in the tropics as well as the pattern shift in the higher latitudes among others all contributed to the changes across North America in early/mid September.

What about other years that had similar long stretches of 80+ degree warmth?

Here were the patterns across the US/Canada in east instance: Notice in most instances, the configuration is very similar.

September Cool To Mid- September Warmth - Part II

Let's go back to the first 10 days of the month. Temperatures were below normal. We had a 5 day stretch of highs in the 60s/70s and lows in the 40s in spots. Then the pattern flipped. Starting on 9/11, the temperatures reached 80 degrees. The first of 12 straight days. 

To have 

Here is an animation of the upper level pattern starting September 6th.  Cool colors are low pressure.  Warmer colors are high pressure. Notice the cool colors over the Great Lakes at the start. See how the ridge of high pressure replaced it. It developed over western Canada, moved east and deepened between Hudson Bay and the Great Lakes. Low pressure stalled in the western US. Southern systems undercut the big ridge as indicated by the cool colors across southern states.

The overall temperatures vs normal starting September 6th:

The difference in average temperature from September 1-10 and September 11-20 was huge.  I compared each year to see where 2024's September temperature flip ranked.  Sure enough, the temperature change was the second biggest jump ever!

Here is the last 30 years for comparison. 1985 is on the left.  2024 is on the right.  2017 had the biggest jump.

The warmth (80 straight days with highs in the 80s) ended up lasting 12 days.  Here are the years that had similar stretches of September warmth.

What was unusual about this year's 80 degree stretch was the OVERALL lack of high humidity.

Here are the daily temperatures (line) in the years above during each stretch with the average dew point for each year:

You can better see the differences when you plot the daily dew points in each year. Notice that this year was lower overall.

Here is a plot of the daily dew points for each year in September since the early 1970s. Cool colors indicate comfortable dew points. Any day with a dew point UNDER 60 is shown with a blue color. Right side is the second half of the month. Notice the frequency of less humid days is much higher after September 15th (black line).

Our First Rain in 17 Days! - Part I

The first rain since September 6th moved through late yesterday and earlier today. 

Radar loop above is from 5PM Sunday, September 22 through 12:30PM Monday September 23.

The top amounts were around 1/4" with most well under 0.1".  A small bulls-eye in southern Cuyahoga county from late evening showers on the 22nd.

Here is the total rainfall between September 7 and September 21.

This was the NE Ohio rainfall on September 6th. I superimposed the drought monitor information over the rainfall contour for reference.

Rainfall vs normal between September 7th and the 21st:

Midwest was just as dry.

Even if you extend this map out to early August, rainfall has been well below normal.

Early summer (June 1 to Auguts 1) was well above normal in the midwest/Central US. Ohio was overall below normal since June 1.

The frequency of storms was also way down over the last 3 weeks. Lightning strikes were scarce across northern Ohio.

Last year was September storms were a bit more prevalent.

Relief Pitching FIP and Team Wins

San Diego, Atlanta and Cleveland have the best relief pitching in baseball. 

Here are the top ten teams Relief Pitching xFIP thus far:

1. San Diego  3.65
2. Atlanta   3.66
3. Cleveland   3.68
4. San Francisco   3.75
5. Philadelphia   3.78
6. NY Mets   3.90
7. Minnesota   3.92
8. Seattle   3.94
9. Miami   3.98
10. Baltimore   4.00

Remember that FIP is a stat that estimates a pitcher's run prevention independent of defense. It's based on only Strikeout, walks, hit by pitches and home runs allowed. xFIP finds a pitcher's FIP, but it uses projected home-run rate instead of actual home runs allowed. The home run rate is determined by that season's league average HR/FB rate.  FIP uses the ERA scale. More can be found about the FIP and xFIP calculations on Fangraphs HERE

Since we don't have xFIP prior to 2002, I used overall relief pitching FIP and compared team win total for each team since 1997.

FIP is on the y-axis. Each season in the x-axis. The higher the FIP on the y-axis (using the ERA scale) the worse the relief pitching.

Red dots below are the teams with 95 wins in each season since 1997. Notice that only 26 teams of the 119 teams who had 95 wins since 1997 had relief pitching FIPs higher than 4.00.  That's only. 21.8%.  

Of course many things can happen in the playoffs.  For fun, how many of these 95+ win teams since 1997 won the World Series? 

Here are the other World Series winners who didn't win 95 games.

The top 5 worst Relief Pitching FIP World Series winners:

2023  Texas Rangers

2010  San Francisco Giants

2006  St. Louis Cardinals

2000 New York Yankees

1997 Florida Marlins

Each of these teams made up for their relief pitching deficiencies with either top 10 starting pitching or top ten ability to create and score runs.

Is Late August/Early September Heat More Frequent Nowadays?

Today the temperatures reached the lower and mid 90s across not only Ohio but much of the lower Great Lakes and Ohio Valley. The question of whether or not late season heat is becoming more frequent in northern Ohio always surfaces during heat like this.  

High temperatures August 27th:

Heat Index reading on August 27th:

So how do we answer this question?  First what time period are we looking at when we say "late August/early September"?  I like to use the last week of August and first week of September. A fourteen day period that is a decent duration sample size.

August 25 to September 7

What about temperature?  First, let's take look how many instances each year the high temperatures reach 90 degrees or higher during this 14 day period? (Given the forecast we could conceivable hit 90° four times by the end of the week).

Contrary to some of our recollections, its been 6 years since we had a late August stretch of 90+ similar to this year.  This actually occurred the most frequently in the 1950s. The early 2000s are a close second with high occurrences in 2010, 2012, 2016 and 2018.  With the exception of a few years like 1973, 1983, 1991 and 1993 it rarely happened in the 1960s, 70s, 80s and 1990s.  

What was interesting about the late August/early September of 1953 period was that we were above 90 degrees eleven of the fourteen days. 

The top number is the high temperature. The bottom number is the highest heat index that day.  Notice the extreme humidity didn't accompany the heat initially. In fact, dew points were very dry the first 6 days of that stretch from August 25 through the 30th. It wasn't until later in the period -- day 7 of the 11 day stretch -- that the heat index rose above 100° for 4 straight days.

Now compare 1953 and its 10 days above 90° to the 7 day stretch in 2018.

What about the overall average high temperatures during this 14 day period.  Are there any changes locally?  Here is a look each year since 1980. 2016 and 2018 were well above normal in high temperatures as was 2010 and 2012.  

Were these warm, late season stretches just relegated to northern Ohio?

Notice that most of these late season hot periods were centered over the Great Lakes, Ohio Valley and portions of New England and eastern Canada while the western US experiences well below normal temperatures.  Below are the temperatures above normal (warm colors) and below normal (cool colors) across the US and Canada.

The bottom line is that long hot stretches don't happen every year in late August/early September like many remember.