Tropical Storm Elsa Drenches Southern New England
After making landfall in Florida and moving over much of the East Coast of the United States over the past two days, Tropical Storm Elsa crossed southeastern New England on Friday, July 9, 2021 and passed approximately 40 miles to the southeast of the Observatory at mid-day. Torrential rain arrived early in the morning, and a total of 2.91 inches of rain was measured through 1 PM. A total of 0.24 inches fell before 7 AM EST, and another 2.67 inches of rain was measured for the six hours from 7 AM to 1 PM EST. With additional rain through the end of the day, the daily rain total for July 9th of 3.02 inches was the second highest for the date and the seventh highest for any calendar day in July. The monthly precipitation total for the month through July 9th is 8.88 inches, which is already the fifth highest on record for July only nine days into the month.
With the center of the storm crossing eastern Massachusetts on the 9th, the winds were only breezy with gusts near 30 mph. As the storm began pulling away at mid-afternoon, the wind backed to the northwest with escalating speeds. A peak gust to 40 MPH from the WNW was recorded at 2.54 PM EST as Elsa was moving offshore to the east of the region.
The temperature has remained on the cool side through the storm, but the dew point has been near 70 deg F, indicative of the tropical moisture that the storm brought into the area.
Below is some historical context for the extreme rainfall recorded at the Observatory due to Tropical Storm Elsa.
BHO Highest July 9 Precipitation, inches (1885-2021): 1) 3.74 on July 9, 1921 2) 3.02 on July 9, 2021 [T.S. Elsa] 3) 1.37 on July 9, 1964 4) 1.17 on July 9, 1962 5) 1.10 on July 9, 1895 6) 0.92 on July 9, 1930
BHO Highest July Calendar Day Precipitation, inches (1885-2021): 1) 4.46 on July 1, 1915 2) 4.01 on July 27, 1979 3) 3.74 on July 9, 1921 4) 3.54 on July 13, 1996 [T.S. Bertha] 5) 3.32 on July 28, 1911 6) 3.14 on July 13, 1898 7) 3.02 on July 9 2021 [T.S. Elsa] 8) 2.92 on July 27, 1988
BHO Wettest Julys, inches (1885-2021) 1) 11.67 in 1938 2) 10.68 in 1988 3) 10.43 in 1921 4) 9.52 in 1915 5) 8.88 in 2021 [through July 9] 6) 8.47 in 1889 7) 7.62 in 2009 8) 7.55 in 1916
Mike Iacono Chief Scientist Blue Hill Observatory
