While the Northeast endured an abnormally dry May, with drought even on the horizon, Mother Nature flipped to the other extreme for June 2015 and brought parts of the region one of the wettest months on record! Quite a few thunderstorm days and a system reminiscent of a nor’easter all contributed to the month's excessive rainfall. Severe storms also made the headlines on numerous occasions as storms produced widespread damaging winds leaving thousands without power, record large hail, and even a few tornado touchdowns.
Wasting no time, storms and wet weather hit the region on the 1st. A stalled front brought some severe weather and even areas of flooding, particularly between Philadelphia, PA and Washington, DC. Then, the system responsible for the record rainfall across Oklahoma and Texas pushed eastward, bringing the Northeast back to back stormy days through the 5th. The Mid Atlantic was especially hard hit during this time, accumulating 2.00 – 4.00 inches of rain in less than a week. On the bright side, this slew of rainy days helped abate the increasing drought that began in May. Besides the wet weather, temperatures were well below normal during this time. New England experienced record cool high temperatures on the 1st and 2nd with Boston only reaching 49 degrees both days, meanwhile Philadelphia failed to reach 60 on the 2nd.
High pressure finally gained control by the 6th with temperatures bouncing back to summer like readings on the 8th and 9th ahead of an approaching cold front. Severe storms hit the Mid Atlantic on the 8th with 50-55 mph wind gusts recorded at both Washington, DC area airports. Gorgeous conditions followed for the 10th before Mother Nature turned up the heat and humidity. Philadelphia, PA and Allentown, PA even tied record highs of 95 and 92 degrees, respectively on the 12th.
Then, the combination of a stalled boundary and warm and humid conditions led to a very wet and stormy period from the 14th through the 20th. Although New England remained near to slightly cooler than normal, areas further south warmed nicely into the 80s and 90s on most days, providing fuel for numerous showers and thunderstorms. In fact, Baltimore, MD received 3.56 inches of rain during this period! Besides typical summer time storms contributing to excessive rainfall during this active time, the remnants of Tropical Storm Bill pushed into the Northeast on the 20th. Not only did it bring rainfall of up to 2.00 inches, but a potent squall line led to widespread damaging winds ranging 50 – 65mph from Richmond, VA to the Mason-Dixon Line.
Temperatures turned even warmer in the days that followed, peaking on the 23rd. That day, Heat Advisories were in effect in the Mid Atlantic as the temperature spiked to 94 in Baltimore, MD and 95 degrees in Philadelphia, PA. The hot and muggy conditions in place allowed an approaching cold front to produce a very potent squall line that blasted through Maryland, southeast Pennsylvania and South Jersey that evening. Straight line damaging winds reached 72mph at Philadelphia International Airport and 75mph in Medford, NJ leading to thousands of power outages.
To learn how meteorologists tell the difference between straight line winds and torandoes, see our article. Besides intense wind gusts, there were numerous hail reports with even a record large hail stone the size of a grapefruit in Timonium, MD.
The Northeast turned pleasant from the 24th to the 26th before the weather pattern turned active for the final week of June. First, a system reminiscent of a nor’easter hit on the 27th. While the heaviest rain once again missed New England, a generous 1.00 – 3.00 inches of rain soaked Maryland, eastern Pennsylvania and New Jersey. The highest amounts fell in Ocean County, NJ where rain totals approached 5.00 inches! After quiet and cool days on the 28th and 29th, severe weather returned on June 30th. This time around, eastern Pennsylvania and northwest New Jersey were hardest hit with supercells or rotating severe thunderstorms. In addition to golf ball size hail near Allentown, PA, the wind gusted to 64mph in Montgomery County, PA with an EF-1 tornado touchdown in Honey Brook, PA. These supercells knocked down numerous trees and induced widespread power outages with one supercell passing just 2 miles from our Hackettstown, NJ office!
The main headline of June certainly was the record rainfall across the southern half of the Northeast. While North Jersey and eastern Pennsylvania were on the brink of a notable drought leaving May 2015, the very wet pattern of June more than compensated the deficit, bringing 150 – 200% of the normal rainfall and one of the wettest Junes of all time. For more information on the soggy June, see our rainfall article. Only New England and Long Island were without record rainfall which left coastal Connecticut and Long Island in a moderate drought by the end of the month, according to the U.S Drought Monitor. Looking at temperatures, the month finished right around average except for Boston, MA which finished 3 degrees cooler than normal, ranking as the 7th coolest June on record.
