You have to go back 75 years, to the summer before Pearl Harbor, to find a drier spring and summer in the Buffalo area.
Just months before the United States entered World War II in 1941, a mere 9 inches of rain fell on Buffalo from March through July, compared to the 9.07 inches of rain that fell over the same period this year.
In fact, dating back to 1871, this year now ranks as the fifth-driest summer in Buffalo history – out of 146 years.
“This has been the driest five-month period since records were kept out at the Buffalo airport, starting in 1943,” National Weather Service meteorologist David Thomas said Monday.
Of course, rainfall isn’t the only variable creating drought conditions, according to the National Weather Service.
Other factors include:
• Above-average hot summer temperatures that have increased the evaporation rate and quickly dried out the soil.
• Below-normal snow pack level from a mild winter that left drier conditions heading into the spring.
• And the lack of any prolonged rainy period – say, over about five days – that would have softened the ground enough to keep continued rainfall from running off the concrete-hard ground.
“Right now, it’s probably a once-in-a-generation drought,” Thomas said.
He was referring anecdotally to 1988 and 1995 as other years with similar summer droughts.
“From what I’ve heard from local farmers, they haven’t had to deal with dry conditions like this for many years, at least since the 1990s.”
A color-coded map provided by the United States Drought Monitor shows that most of Western New York – all but parts of Chautauqua and Cattaraugus counties – has experienced a “severe drought” through early August. That’s not the most serious category; the monitor also lists “extreme” and “exceptional” droughts.
But that color-coded map of the whole northeast United States shows only a few areas with “severe droughts” this summer: Western New York and sections of Central New York, the Southern Tier, Massachusetts, New Hampshire and Maine.
By contrast, most areas in Chautauqua and Cattaraugus counties are experiencing a moderate drought or merely abnormally dry conditions.
Thomas noted that Western New York last had a “severe drought” fairly recently, in September 2007. But that was in the fall, and thus later in the farming and lawn seasons.
The climate-information website xmACIS2, part of the National Oceanic and Atmospheric Administration, shows that Buffalo’s driest spring and summer since 1871 occurred in 1934, when only 7.75 inches of rain fell from March through July. The next driest totals came in 1898, 1915, 1941 and this year.
Even the small amount of rain that has fallen on Western New York hasn’t done much good in soaking the ground.
That’s because the rain has been too intermittent.
“We need a couple of light rainfalls to soften the ground,” Thomas said. “When the ground is very hard, like concrete or almost like a parking lot, even a heavy rainfall doesn’t penetrate into the ground. It just runs off.”
For that reason, Thomas noted that we’d be better off having five days in a row with 0.4 inches each, compared to the same 2 inches over a six-hour period.
“We’ve rarely had any prolonged periods where we’ve had even minor accumulations back to back,” he added.
Thomas also cited two factors that can help explain the lack of rain this spring and summer:
• The upper-air wind direction has been from the northeast more often than usual.
“That’s typically a dry wind for us,” he said. “We’re not getting as much Gulf moisture coming in from the south.”
• The timing of the cold fronts we have experienced. They’ve come mostly overnight.
“The cold front gives a little extra lift to the showers and thunderstorms,” Thomas said. “You want the cold front coming through in the afternoon and early-evening hours to coincide with the peak heating of the day.”