A Memorial Day weather surprise: the Jersey shore ocean breeze

An aerial photograph shows the New Jersey shore and Atlantic Ocean, seen right, and the towns of Seaside Park (bottom) and Seaside Heights (center), April 27, 2013. (EPA/MICHAEL REYNOLDS)

An aerial photograph shows the New Jersey shore and Atlantic Ocean, seen right, and the towns of Seaside Park (bottom) and Seaside Heights (center), April 27, 2013. (EPA/MICHAEL REYNOLDS)

Growing up at the Jersey shore, I always had mixed feelings about Memorial Day, the traditional start of the summer season and now observed as the final Monday in May. (But at the shore, the “real” summer season was, and is, considered the 9-week period between July 4th and Labor Day.)

On the one hand, it meant school would be out soon and I could look forward to some R & R (although I worked throughout), but on the other hand it meant that hordes of city dwellers would soon be “descending” on our resort town.  Although they were the life-blood of the local economy, prices of everything would soon be soaring.

As the holiday approached, predictions of a particularly warm, sunny weekend (something we definitely do not expect this Memorial Day–at least the warm part) would drive many folks (mostly New Yorkers) down to shore resorts such as mine (Asbury Park) to get some “beach time.” It was the perfect opportunity, they reasoned, with the lower prices and the smaller early-season crowds (except for the actual Memorial Day weekend).

Arriving in late morning, people would set up their beach umbrellas, blankets, etc. as far as the eye could see.  Working on the boardwalk during mid-May weekends and being an avid weather-watcher (even then), I waited with anticipation—and some amusement—for the sudden exodus.

I knew that folks would be scurrying off the beaches soon, but not because late May Jersey shore water temperatures are still mostly in the 50s, as they are at most Maryland beaches in May. Most out-of-towners came to expect that. But what they never seemed to remember was that the great disparity between the chilly surf temperatures and adjacent off-shore air temperatures could generate a cruel deception.

A conceptual illustration of the ocean breeze (National Weather Service)

A conceptual illustration of the ocean breeze (National Weather Service)

The deception would be the development of the dreaded “on-shore” southeast sea breeze. Under ideal conditions (a relatively light late morning land breeze with air temperatures in the 80s), this would occur between 11:30 a.m. and 1:00 p.m., when the off-shore land breeze cannot continue to overcome the dynamics of the developing sea breeze.* In minutes, the change in wind direction would send temperatures plummeting to as low as the upper 50s, often under clear skies. The cool air would obviously be most intense at the beachfront and usually would hardly even be noticed at the western edge of town, unless other factors were at play, causing the cool air to move further inland.

But the wind shift from southwest to southeast was dreaded only for the beachgoers; for boardwalk merchants, it was a bonanza, extracting all but the hardiest of sun worshippers from the beach back to the boardwalk—where they could spend their money.

People walk along the newly rebuilt boardwalk in Seaside Heights, N.J., Saturday, May 18, 2013.  (AP Photo/Mel Evans)

People walk along the newly rebuilt boardwalk in Seaside Heights, N.J., Saturday, May 18, 2013. (AP Photo/Mel Evans)

Those of us who were shore residents often chuckled at those “hardy” ones, determined to get in some sun, despite the temperatures.  Under other conditions, they were the same ones who, after “coming down from the city,” believing it would be sunny and warm,  would brave sudden cloudy, even rainy, spring weather under their beach umbrellas, determined to get what they came for—even if it wasn’t there.

At the time (1950s and 60s)—probably even now—warm season weather forecasts tended to focus on overall inland air temperatures, with only minor mention toward the end, of something like “cooler at the shore.” But that phrase might mean a shortfall of as much as 30 degrees in afternoon temperatures at the immediate shoreline in April and May.

Of course, as the season progresses and water temperatures increase, this differential decreases markedly, so that what was an unpleasant assault on the senses in late spring becomes a refreshing sea breeze in August, with temperatures dropping, perhaps, from the 90s into the upper 70’s.

By the way, the average high and low temperatures for Memorial Day (May 27) this year at Reagan National Airport (DCA) are 79 degrees and 60 degrees, respectively.  But over the last 3 years, temperatures have exceeded 90 degrees on each Memorial Day, with a 96 degree reading recorded in 2011.

For the history buffs, Memorial Day was originally called Decoration Day because, during the post Civil War period, the ancient custom of honoring fallen soldiers by “decorating” their graves became commonplace.  Usually, the graves were decorated with the American flag.  With the advent of World War I, the custom was expanded to honor war dead from all of our conflicts.

May 30, 1868, is generally considered to be the first “official” Memorial Day, as established by General John A. Logan, leader of an organization for Northern Civil War veterans, in 1862.  May 30th continued to be the date that America would honor its war dead until 1971, when the “Uniform Monday Holiday Act” changed the observance to the last Monday in May.

*(As many of our knowledgeable weather buffs probably know, the so-called sea breeze develops when, in the absence of a strong land breeze, warm air overlying a land mass rises near a cool body of water, only to be replaced at lower levels by the cooler air overlying the water.  It is experienced, to one degree or another, in most parts of the world where cool-to-cold water temperatures are contiguous to a warm air mass over land.  The reverse process occurs at night.)

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