While there were ups and downs this meteorological summer (June through August), in the end the summer of 2013 was rather average.
The average temperature was 71.6° or .2° below average. There have been 66 cooler summers than this past one and 75 warmer summers.
Rainfall totaled 10.14″ or 1.91″ less than the average of 12.05″. There have been 66 drier summers and 76 wetter summers compared to 2013.
Some other items of note pertaining to this past summer:
- There were just 9 90° days (days in which highs hit 90 or more), last summer there were 40
- June had nearly 3″ more rainfall than normal but July was down more than an inch and August more than 3″ from average
- 96° was the hottest high this summer occurring on July 9th and August 27th & 30th
- 43° was the coolest low occurring on June 2nd and June 3rd
- The longest streak of below average highs occurred between July 23rd and August 5th, 14 days in a row
- The longest streak of at or above average highs was between August 20th and 31st with 12 days in a row
There has been a remarkable reversal in the longer range outlook from the Climate Prediction Center for the start of December. Just a few days ago the forecast had most of the country, including the midwest, outlooked for overall above average temperatures (see top image below). The most recent forecast for roughly the same period now has the midwest and much of the northeast outlooked for cooler than average weather (see bottom image below).
OLDER FORECAST FOR SEPTEMBER 3-9
LATEST FORECAST FOR SEPTEMBER 4-9
First things first…
It will be a scorcher today with highs in the lower to middle 90s and heat index values approaching 100°. A front will come through this evening with the hope for at least a few thunderstorms to bring some much needed rain to the area. This weekend might feel less like Labor Day weekend and more like July 4th weekend (at least Saturday and Sunday) with highs typical for July and ample humidity too. Then a stronger front comes crashing through late Sunday to usher in cooler Canadian air as our highs slip back into the 70s for Labor Day and Tuesday.
23 years ago today the most powerful August tornado to strike the United States ripped through the southwest suburbs. The Plainfield tornado killed 29 people and injured over 350 others.
The storm that spawned the tornado developed first in southern Wisconsin and then moved southeast across the state line towards Plainfield and Joliet. Most tornados tend to move from the southwest to the northeast. The movement of the storm wasn’t the only thing unusual about it though. The Chicago office of the National Weather Service noted several things that made this tornado unique:
- It was the first ever rated greater than F3 in August in the state of Illinois.
- It was only the second killer tornado to occur in Illinois during the month of August.
Twenty-three years later it remains the only F5/EF5 tornado ever documented in the U.S. during the month of August. In fact, only 0.2% of all tornadoes in August have been rated F4/EF4 or greater.
The tornado was shrouded by low clouds and rain, making it difficult to see. As a result, no known photographs or videos of the tornado exist.
- It is the only F5 tornado to strike in the US during the month of August.
It is the 15th most damaging tornado between 1890-1990 according to the National Severe Storms Laboratory ranking. It left a damage path over 16 miles long that was as wide as 1/2 mile at times. The visible satellite imagery (see above) from that day shows the storm growing rapidly that afternoon.
It appears summer will end steamy. The worst of the heat will be today and tomorrow but temperatures should remain above average all the way through Labor Day weekend. Our RPM model is indicating the combination of heat and humidity will make it feel like nearly 100° today and over 100° for most areas on Tuesday (see images below). The National Weather service has more detailed information on how the heat index is derived along with the hazards associated with excessive heat.
Tomorrow’s high will be in the middle to upper 90s. It will rival July 19th as the hottest day of the year. O’Hare hit 96° on that date. A “back door” cold front will bring in some relief Wednesday and Thursday turning winds off the lake but highs will still be about 5 to 10° above average. The longer range 6 to 10 day and 8 to 14 day forecasts from the Climate Prediction Center outlooks us for above average temperatures overall through the first week of September.
After a fantastic Friday with seasonable temps and comfortable relative humidity, we will warm up this weekend and then see a heat wave hit next week. Computer models are fairly consistent in shifting the main jet stream north and allowing hot and humid air to flood our region. We could see a streak of at least 4 90° days starting Monday. The combination of heat and humidity will make it feel like close to 100° at times.
This upcoming week could rival the four day streak of 90° days that occurred back on July 16-19. So next week’s streak would be only the second of its kind this summer. O’Hare has hit 90° or above only 7 times this year. This final steamy stretch of August comes after a relatively cool start and middle of the month. The average August temperature is 71.1° (that includes both the daily high and low) which is 1.9° below average for the month so far.
Surf might be up today (see above image) but be careful in the water. The National Weather Service has issued a beach hazards statement because of “high wave action and dangerous swimming conditions expected at times today”. Strong structural and rip currents are expected.
Yesterday’s high of 88° at O’Hare made it the first above average day we have seen in just over a week. We will crank the heat and humidity up just a notch today with highs for many of us hitting 90°. That would make it the first 90° high in a little over a month. Despite a couple of cooler days coming up tomorrow through Saturday, heat and humidity will build back by the end of the weekend and we should start off next week steamy with highs again near 90°.
The longer range outlooks from the Climate Prediction Center keep the heat coming. Both the 6 to 10 day and 8 to 14 day forecast (see images below) have us outlooked for above average weather. That would take us right through the end of climatological summer and past Labor Day weekend with warmer than average temperatures overall.
It has seemed more like September the past few days than the middle of August. Today will be the fourth day in a row below average. So far 11 of the first 15 days of August have been below average. The pattern that has kept us so cool is about to change dramatically early next week. We will transition from cooler than average to right around average by Sunday and then well above by the middle of next week. Perfect timing for the 55th annual Air & Water Show (see photo above) with abundant sunshine and highs in the upper 70s and low 80s this weekend with comfortable levels of humidity. We will crank up the heat and humidity next week with possibly the first 90° high we have seen in nearly a month coming either Wednesday or Thursday.
The longer range forecast keep the heat coming. Both the 6 to 10 day and the 8 to 14 day forecasts from the Climate Prediction Center have us outlooked for above average temperatures. That would take us through nearly the end of August.
July was the 341st month in a row with a warmer-than-average global temperature. That is more than 28 years of above average global temperatures. It was the 5th wettest and 30th warmest July on record for the contiguous United States.
Here are some more climate highlights for July from the National Climatic Data Center:
- 5th warmest July on record for Alaska
- Alabama, Arkansas, Mississippi, and Tennessee had July temperatures that were among their ten coolest on record
- 13 eastern states had one of their ten wettest Julys on record
- Florida had its wettest July on record
- Oregon had its driest July on record
- there were slightly more record cool daily highs & lows (2846) than record warm daily highs & lows (2560)
This year is on track to be another warmer-than-average year globally. It is a long term trend as the graphics below from Climate Central illustrate. This year should become the 28th straight warmer-than-average year.
Today will be the warmest and wettest day of the week. We start the week off seasonably warm with highs near 80° but after a cool front sags south through the area later today, its 70s and sunshine for the rest of the week. So there are no 90s in sight and none in the forecast at least through early next week. So far this year there has only been 6 days with highs of 90° or more at O’Hare compared with 45 last year at this point. 4 of those 45 days in 2012 had highs well above 90° topping out at 100 or more.
We are not alone in experiencing a relatively cool summer. The National Climatic Data Center reports that record lows have outpaced record highs nationally so far this year. Year to date there have been 8442 record lows compared to 7068 record highs. That is a remarkable reversal from 2012 when year to date there was 2,831 record lows compared to a whopping 27,422 record highs. In other words, at this point last year record highs outpaced record lows by a ration of nearly 10 to 1.
The 6 to 10 day forecast from the Climate Prediction Center seems to offer hope for some warmer weather towards the end of the month. Far northern Illinois is outlooked along with the rest of the midwest for above average temperatures during the period. Cooler than average temperatures are expected south and east of here.
It might be August but it will seem more like mid-September today with highs only in the 70s. Each and every day of our 7-day forecast is calling for below average high temperatures with only 2 days hitting 80° or more. The summer stats add up to a cool summer so far. More than half of our summer days have seen temperatures below average. While we did warm up on Wednesday with our second straight day above average, that followed a streak of 14 days that were below average.
The longer range forecasts keep the cool coming. Both the 6 to 10 day forecast and the 8 to 14 day forecast from the Climate Prediction Center have us outlooked for cooler than average weather overall. If that verifies, that means cooler than average weather can be expected through the third week of August.