Humid Summer of 18 Ends Autumn Begins & The Tropics
If you were under the impression that the summer of 2018 was the most humid summer in many years, your impression was correct. When we look at the number of hours the dew point was above 70 degrees, this summer was oppressive. Take a look at the numbers from Lancaster.
The dew point temperature is used to calculate the relative humidity. If you lower the air temperature to the dew point temperature, the humidity would be 100 percent. When the dew point is 70 or high it is oppressive. Looking at the chart above Lancaster spent over 800 hours with dew points at 70 or higher. This is the highest level in 45 years! To put this in perspective, 800 hundred hours would be the equivalent of 32 plus days of continuous oppressive humidity. It certainly seemed like it lasted that long while we were in it. The excessively wet summer certainly didn't help matters and goes a long way to explain what happens when there is a ton of tropical moisture around.
York data is a bit more limited with the spike up above 600 hours making it the highest since 1996. This does not include the month of September otherwise the numbers would be even higher.
Meanwhile we switch to fall on Saturday and we do have a weather front approaching tonight. There could be some showers and thunderstorms with this front but the will be weakening as they move eastward. This weekend we will be dealing with this front stalling out and that will mean perhaps some rain Saturday night into Sunday and we will be fighting clouds the rest of the time.
The tropics look like they may be getting a bit active this weekend but nothing here poses any threat to the US. METEOROLOGIST JOE CIOFFI HAS MORE ON THIS IN HIS LATEST POST.