Eastern May Rain Fatigue; Any Break Ahead in June?

Jon Erdman
Published: May 30,2017

  

If April showers bring May flowers, some in the rain-fatigued East are wondering what a soaked May will bring.
After a long winter, followed by early-spring rain and late-season snow, some in the Northeast and Midwest tend to get itchy with persistently cloudy, wet weather in May.

The grounds crew pulls the tarp on the field in the third inning as the rain causes a delay in the game between the New York Mets and the Miami Marlins on May 6,2017 at Citi Field in the Flushing neighborhood of the Queens borough of New York City.
(Elsa/Getty Images)

"It's hard to believe it's almost summer," said weather.com digital meteorologist Brian Donegan, from central New York.
"I'm just waiting for the days when I can go outside without a long-sleeve shirt or light jacket for more than a few days a time."
It's even had an effect on the baseball season.
According to Major League Baseball, through the May 26 postponement of the Detroit Tigers - Chicago White Sox game, there had been more postponements in less than the first two months of 2017 (26) than all of 2016.
Rather large swaths of the Northeast, Midwest and South have been significantly wetter than average in May.

May 2017 month-to-date rainfall departures (inches) through May 28 in the eastern half of the U.S. The largest wet anomalies are shown in purple, while dry anomalies are shown in progressive shades of yellow, orange and red.
(NOAA/NWS)

A number of locations are already on pace for a top five wettest May on record, according to the Southeast Regional Climate Center.

May's Misery - Rainfall Statistics Through May 29
(Data: NWS, SERCC)

	May 2017 Precip. (inches)	May Average Precip. (inches)	Record Wettest May	May Days With Measurable Rain
Atlantic City, New Jersey	7.48	3.34	8.80 (1948)	13
Bangor, Maine	6.18	3.57	7.65 (1989)	15
Montgomery, Alabama	12.29	3.53	12.01 (1978)	11
Richmond, Virginia	7.57	3.78	9.79 (2016)	15
Savannah, Georgia	11.41	2.98	11.13 (1915)	7

As of Tuesday, Atlantic City, New Jersey, had nine straight days with at least a trace of rain since last Monday.
In Bangor, Maine, only two of the first 15 days of the month were completely dry.

People walk in the rain in Times Square as flash flood warnings are in effect for the New York area on May 5, 2017, in New York.
(Kena Betancur/AFP/Getty Images)

While New York City's Central Park wasn't on pace for a top five wettest May, due in part to its very long period of record, all three major airports, JFK, LaGuardia and Newark, were on pace through May 28.
If it wasn't for their first May heat wave in 16 years, namely, three straight days in the 90s from May 17-19, the month may have given no hint that summer was ahead in the Big Apple.
And pity parts of New England, who spent Memorial Day struggling to get out of the upper 40s with a soaking rain.
(FORECAST: 4 Things We're Watching in the Weather This Week)

Why So Wet?

To explain this waterlogged month, let's take a look at the jet stream.
Blocking high-pressure aloft became persistent and pervasive in May near Greenland. In fact, it became so strong it shattered records for May dating to 1948, as measured by an index called the North Atlantic Oscillation.
Why does this matter?
Blocking highs in the atmosphere can force the jet stream into large north or southward meanders. One such southward plunge, or trough, repeatedly camped out over the eastern half of the U.S. in May.

The persistent jet-stream pattern in the East in May.

Associated with each one of these jet-stream plunges is wet weather. At times, it was a deluge of heavy rain with a tropical moisture connection. Other times, it was rounds of showers, dropping just enough rain to dampen an afternoon picnic or hike.

Forecast: June Swoon?

Does the arrival of the first core summer month (at least meteorologically speaking) offer any hope of a drier, sunnier pattern?
(MAPS: 7-Day U.S. Rain Forecast)
The short answer is "not right away."
There will still be upper-level blocking high pressure to the north, which will keep the southward plunge of the jet stream generally over the East the rest of this week into next week, as well.
While this doesn't mean it will rain every day, there may be more wet than dry days into next week.
(FORECAST: New York | Boston | Washington D.C. | Atlanta | New Orleans | Chicago)

Eastern Five-Day Forecast

So, if you see a dry day in your forecast and have been itching to get outside and enjoy it, you may want to burn a vacation day, if it's not a normal day off.
(MORE: June Temperature Outlook)
And pray for that stubborn jet stream pattern to stop throwing shade.
Jonathan Erdman is a senior meteorologist at weather.com and has been an incurable weather geek since a tornado narrowly missed his childhood home in Wisconsin at age 7. Follow him on Facebook and Twitter.
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