Feast Or Famine: What’s Behind The Recent Sudden Change In Rainfall?

Weather

Back on June 30th, Harrisburg was running over 4 inches below normal for yearly rainfall, raising fears for yet another abnormally dry summer. But just like that, we flipped the switch. Almost eight inches of rain has fallen in just the first 17 days of this month, making it our wettest July to date. So, what caused the sudden change and is this what we can expect for the rest of summer?


Throughout April, May, and June, our weather was dominated by high pressure with origins from Canada. This kept our flow largely out of the northwest, which brings mainly dry weather to Pennsylvania. In these three months, we picked up only 7.62″ of rain, which was around 4″ below normal.


Fast forward to July and a pattern change took place. An area of low pressure set-up shop to our west, and a strong, persistent Bermuda high developed, pumping heat & humidity northward. Through July 17th, we’ve picked up more than 10 times the rain from the same dates last July.


But at what expense? 

The more amplified pattern has led to extremely dry weather across the western third of the country, where droughts and wildfires have become common this summer. Currently, over 50% of this region is in an extreme to exceptional drought, with not much relief expected anytime soon.


The weather pattern will look a little different going forward. As we head through early August, a strong ridge of high pressure will set up across the central US. While this won’t mean a lot of rain for us, we will see several opportunities for rain as storms ride around the periphery of this ridge…they just won’t be as slow-moving and heavy like earlier this month. Overall, rainfall for late-July and august should be close to normal, with many more 90-degree days expected. For abc27 news, I’m meteorologist Adis Juklo.

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