Yesterday, September 22, the first day of Fall, was another scorcher in Birmingham. According to AccuWeather, temps have topped 90 degrees in Birmingham for 11 straight days and 19 out of 22 days this month. Are we in the midst of a historic heat wave? What’s up with our weather?
To get an idea, Bham Now submitted a few written questions to WIAT CBS 42’s Chief Meteorologist Ashley Gann for her thoughts about the current heat wave. Here was her response.
Before diving into the written responses to Bham Now’s question Gann noted that Birmingham had experienced the 10th day in a row with temperatures at or above 90° (her response was on Friday evening) but we still haven’t hit 100° since 2016.
She added, “So, even though it’s hot now, many of our September records were set with highs in the low 100s.”
Moreover, in 2016, she wrote we had 13 consecutive days with temps at or above 90°.
Onward to the Q&A.
Bham Now: According to AccuWeather we had 11 straight days of over 90 degrees in Sept. and only two days under 90 degrees all month? Nights are staying warmer and not cooling off.
Can you explain this?
Gann: I don’t think that this September is record breaking, but it is above average.
Climate speaking, September and October tend to be our driest months (see chart), and rain can drive temperatures fluctuations. For example, all the days we’ve had rain, temperatures have stayed in the 80s.
But, we’ve had a very dry September. Dry air heats for effectively and efficiently. Plus, these last few days, we’ve been sitting under a heat dome known as a ridge (or area of highs pressure). It’s easy for those highs to climb into the mid and upper 80s when that dome sets in. And it isn’t just impacting Alabama but a good portion of the east coast. During years that we’ve had cooler Septembers, we have had more rain, and that rain is generally caused by tropical systems. Most of the tropical activity has avoided the Gulf this year, at least during September.
Bham Now: Did the hurricanes have anything to do with these temperatures?
Gann: Now, to the tropics. First off, although it would be great to make a correlation between our local weather and the tropics, it’s really difficult to do that because what happens in the tropics really doesn’t have any bearing on what is happening here locally.
The middle 2 weeks of September are what is known as the “peak” of hurricane season. Statistically, more tropical weather has happened during those 2 weeks than any other weeks during hurricane season. I would say that mother nature was right on time this year.
Notice this week…absolutely quiet in the oceans and the gulf! How crazy is that?? We go from 3 named storms, at the same time, to nothing, all within a week. Factors like winds in the upper levels of the atmosphere, sea surface temperatures, and the placement of the Bermuda high all play a part in how tropical weather forms, how intense those storms get, and where those storms ultimately go. Temperature drives sea surface temperatures, which is like the equivalent to the fuel a storm needs to survive and grow.
Bham Now: Have you ever experienced a September like this before?
Gann: I personally think we live in an air conditioner friendly world. So, hot days just seem hotter than they ever have. I grew up in East Texas, my grandparents had a few window units, but no central air. Summers were hot and we played outside a lot. We drank a lot of water and lemonade. Rode our bikes ’til dusk. Now, most people are indoors…from their jobs to kids playing video games or having more access to digital technology. I really think our bodies are acclimating to 72° world, which ultimately makes a hot day from 30 years ago feel like an unbearable day these days. That may have a little to do with it.
So, in summary. Yes, it’s been an slightly above average September, but it’s actually been an average summer over all. We’ve not had any record heat this September and we haven’t hit 100 once in over 2 years.
Bham Now: When is Fall coming?
Gann: Fall officially begins tomorrow, but it does look like we will see a warmer than average start to the season. I think by the 2nd week of October temperatures will start cooling.