New England Drought Affecting Fall Foliage?

Left: Weymouth Back River, MA Sept 2014 (license). Right: Typical foliage scene from October 2014

Folks living in New England over the past few months have experienced persistent dry spells and paltry rainfall totals that have led to consecutive months with high monthly precipitation deficits. While Hurricane Arthur brushed the New England coast on July 4th and alleviated some of the ongoing dryness with its 2 – 6 inches of rain, every other month from June to September 2014 has ranked within the top ten driest on record. The graph below illustrates the dry pattern New Englanders have endured since May 2014. In particular, the period from August 1st to September 30th was exceptionally dry thanks to high pressure keeping a strong hold over New England and blocking impending coastal systems. Rainfall in August ran 1.00 – 2.50 inches below normal which was followed by an even drier September as deficits topped to 2.50 – 3.50 inches! New Bedford, MA ranked the period from August 1st – September 30th the driest on record only receiving 2.86 inches of rain, when it typically sees 7.67 inches. Closer to the coast, it was the 3rd and 5th driest such period in Plymouth, MA and Boston, MA which received only 30 – 35% of the normal rainfall. The last time the region saw a similarly dry August and September period was way back in 1988.

Due to this ongoing dryness, the U.S Drought Monitor placed Rhode Island, eastern Massachusetts and Connecticut in a moderate drought on September 23, 2014. According to the U.S Drought Monitor, a moderate drought means the region has experienced some damage to crops or pastures and streams, reservoirs or wells are low and thus, some water shortages are developing or are imminent. New England rivers have responded to the ongoing dryness and are running well below normal. The stream flow at both the Charles River in Waltham, MA and the Quinebaug River in northeast Connecticut had a stream flow that’s just 19% of normal as of October 8, 2014.

So what are some consequences of such a dry pattern? Well, the fact that trees began changing colors as early as late August and early September this year can be connected to the recent weather pattern. Thanks to the dry pattern seen over the summer and early autumn combined with plenty of sunny days and cool nights in September, the photosynthesis process in the trees slowed down and caused colors to change ahead of schedule.

Besides timing, the weather conditions have also played a role in determining the vibrancy of fall foliage color. The most aesthetic colors occur during years with a wet spring and dry fall and looking back at this year’s weather, we experienced just that. Furthermore, colors should also be vibrant since the tropical activity in the Atlantic Basin has been very quiet. In other words, high winds have not damaged trees or caused them to lose leaves prematurely. Enjoy the remainder of the fall as signs point to a beautiful season!