July 2019: Heat Waves and Thunderstorms

August 2, 2019 // Article by: Chris Castellano

Summer made its presence known in July 2019 with frequent hot stretches, significant rainfall, and severe weather events throughout the month. In fact, the number of days which featured above normal temperatures overwhelmingly exceeded the cooler days. As a result, it was a period that finished above normal in terms of both temperature and precipitation.

SEVERE AND SOGGY FIRST WEEK IN THE MID-ATLANTIC

July began where June left off in the Mid-Atlantic, with an active week of heavy rainfall and bouts of severe weather from Baltimore, MD to Trenton, NJ courtesy of several slow-moving fronts that made their way through the area. The first of these waves pushed through on the 2nd, in the form of a surface boundary which resulted in widespread reports of wind damage in Maryland and southeast Pennsylvania.

The most significant event followed a few days later, with the arrival of a more potent cold front and severe thunderstorms. In this instance, reports of downed trees and wires rolled in from Boston to Washington D.C. The storms were even enough to produce a tornado, which was actually captured by a surveillance camera in Mount Laurel, NJ. Though wind damage was not extensive, one unlucky car was flipped over by the brief spin-up.

This same front proved to be tough to be rid of, as it slowed and became stationary over the Mid-Atlantic. Once again, this meant soaking rains from heavy thunderstorms on the morning of the 8th, with an eye on the immediate downtown of our Nation’s Capital. Given its urbanization and high population, this heavy thunderstorm activity brought significant impacts to the city in terms of flooding. To make matters worse, the event coincided with the morning rush hour, which left many motorists stranded. Washington’s Reagan National Airport collected 3.44” of rain, which was a record for the date, and the 4th highest 1-day July total in its history.

A few more severe weather events producing mainly wind damage dotted the rest of July. While a majority of the impacts were felt in the Mid-Atlantic, New England eventually joined in toward the latter half of the month. A tornado became one of the main stories (interestingly over Cape Cod), which tore the roof off of a hotel in West Yarmouth, MA. New England’s most significant and widespread severe weather episode wrapped up the month on the 31st, when potent thunderstorms brought down 70-75 mph gusts!

THE DOG DAYS OF SUMMER

Along with the active weather during the month, heat waves frequented the entire I-95 corridor through New England, as a more persistent ridging pattern finally took over. While heat and its impacts can vary from region to region depending on tolerance and other factors, a heat wave in the Northeast is met when high temperatures hit 90 degrees or higher for three consecutive days. Baltimore and D.C. naturally were impacted the most by this, averaging high temperatures of 91.7 and 90.9 respectively. While technically three separate heat waves occurred, the one in the middle of the month spanned 12 straight days in D.C. Baltimore managed 11 consecutive days around the same time, and even recorded back-to-back days where the mercury reached the century mark.

The heat was felt northbound as well. Overall temperatures finished 3 – 6 degrees above normal from Philly to Boston. Urban impacts also made for sweltering nighttime numbers as well, especially in Newark which recorded a +7.1 degree departure from normal with an average low temperature of 71.7 degrees.

HOT, RAINY… BUT NOT RECORD-SETTING

While July 2019 certainly was hot at times, historical numbers provide a reminder that it is… summer. The heat did not break records, but it did finish highly in the rankings. Baltimore’s aforementioned 91.7 degrees hit 5th in recorded history at Baltimore-Washington International Airport. Boston’s average of 86.6 degrees, though lowest of all the big cities due to its geography, was enough to get Logan Airport to the 3rd warmest on record.
  

City

Average High

Rank

Baltimore

91.7

5th

Washington D.C.

90.9

11th

Philadelphia

89.8

12th

Newark, NJ

89.5

10th

Central Park, NYC

87.1

19th

Boston

86.6

3rd

 

 

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