 |
| If you water enough, flowers thrive in this hot July. Photo taken Sunday near the front door of my St. Albans, Vermont house. |
Enjoy it, because this fresh air is only temporary. Unfortunately, a nice soaker of a rain is going to mostly miss northern Vermont, which could use a good dousing.
As expected, the cold front has gotten hung up in southern New England on into the Ohio Valley. Little disturbances rippling along the front will create a storm day from Kentucky to southern New England.
Flood watches are up for a good stretch between Tennessee and the New York City area. Strong storms could also cause some damaging wind gusts and perhaps a brief spin up tornado in this stretch, too.
The soaking rains will work their way up into southern Vermont, but will struggle to reach the north. North of Route 2, there will be less than a tenth of an inch of rain.
This July is shaping up to be much like last July. It's been quite hot and dry across northern areas (though not as hot as last July, thank goodness.) Like last July, the heavy rain and flooding has been going on from southern New England into the Middle Atlantic States.
The comfortable weather up here in northern New England looks like it won't last as long as originally hoped. The temperature will start to creep up starting Thursday. By the weekend, it's going to be quite warm and humid again, but not as bad as it's been the past couple of days.
Right now, early indications are that temperatures will be in the mid to upper 80s over the weekend, with somewhat sticky dewpoints in the mid-60s. (A dewpoint over 60 is a wee bit humid, over 70 and it's oppressive, so we'll be somewhat in the middle.)
As usual, people are wondering if the recent heat had anything to do with climate change. That climate change might have influenced the heat wave and made it a little worse, but heat waves do happen in the summer, as we all know.
Nights during this heat wave were the worst, and set some records. Boston only got down to 83 degrees Sunday tying the record there for the highest minimum temperature for any date.
Very high humidities prevent nighttime temperatures from falling much.
Heat waves seem to have gotten more humid in recent decades. I think part of it might be climate change, as a warmer general atmosphere can hold more water, making it more humid. Another reason for the increase in humidity is probably land use.
During the epic dust bowl heatwaves of the 1930s, which brought by far the highest temperatures on record to the Great Plains and parts of the Midwest, poor agricultural practices led to a rather barren landscape.
With less vegetation, there was less humidity due to reduced transpiration from plants. Temperatures in the 1930s soared well into the 100 to 120 range in the middle ofthe country, but dew points during the worst heat waves were in the dry 50s for the most part. Lower dew points can create higher daytime high temperatures but lower overnight lows.
Nowadays, places like Iowa are wall to wall corn and soybean fields, which means lots of plant transpiration adding water to the air. The biggest hot spells of the summer now can bring dew points as high as 80 degrees to Iowa. That happened there this past Friday and Saturday, for instance.
I'm not aware of any particular research into this, but I'm guessing heat waves in Vermont were generally not as humid a century ago as they are now. Again, climate change would be a a part of that but land use is probably playing a sizeable role.
In the 19th century, as little as 35 percent of Vermont was forested, as people cut down swaths of trees for pastureland. Today, the Green Mountain State is roughly 75 percent forested. That's a lot more leaves adding water (and oxygen!) to the atmosphere.
That possibly translates to higher summer humidity.
Just don't start cutting trees to make it less humid. It ain't worth it.
