Soaking rains on a windy Saturday may improve drought conditions — but ruin some outdoor plans
It will be wet and cold at the Penn Relays, and the region's rain trends may be changing.
With the foliage working up a thirst, New Jersey and Chester County under drought warnings, and Philly in its eighth consecutive month of precipitation deficits, a soaking rain this weekend may elicit a certain gratitude.
That is, unless you’re among the tens of thousands attending or participating in the annual Penn Relays or were planning on going to the annual Azalea Garden Spring Fete in the gardens behind the Philadelphia Museum of Art or doing most anything else outside.
In addition to on-and-off rain that could start in the morning and continue well into the night, with perhaps the most precipitation since the February snowstorm, Saturday afternoon is likely to feature early-March temperatures, getting not higher than 50 degrees. A raw east wind gusting to 20 mph is expected.
“It’s not going to be a nice day,” said Alex Staarmann, meteorologist at the National Weather Service office in Mount Holly.
A storm to the south will generate east winds off the ocean, where sea-surface temperatures are in the low and mid-50s. Daytime highs likely will occur close to sunrise, he said, “Once the rain starts,” he added, “it will get cooler.”
The Pennsylvania Horticultural Society got the message and canceled the azalea fete. “It looks like the weather didn’t want to cooperate,” said Sin Gogolak, the society’s spokesperson.
At least the rains are going to fall over a long period, said Chad Merrill, meteorologist with AccuWeather Inc. “It’s not going to be one of those situations when you get heavy downpours,” he said.
Rainfall has been less two-thirds of normal the last 2 months
The rains won’t come close to erasing the accumulating rain deficits in the region. April rainfall at Philadelphia International Airport stood at 1.15 inches through Thursday, or about an inch and a half below normal.
Amounts up to an inch are possible during the weekend, said Lee Robertson, a weather service lead meteorologist in the Mount Holly office. Some areas might get a splash more, he added.
“Whatever we can get we can use right now for sure,” he said.
Precipitation throughout the region for the last 60 days has been less than two-thirds of normal, according to the government’s Middle Atlantic River Forecast Center.
In the Thursday update, the interagency U.S. Drought Monitor had all of New Jersey and the entire Philadelphia region in at least moderate drought, with almost all Chester County in severe drought. Like New Jersey, Chesco is under a state-declared drought warning. The warnings call for voluntary restrictions.
Dryness would be a growing concern in the coming weeks given the rather sudden greening in the region and what is likely a healthy thirst among the foliage. The plants evidently have prospered from the weather supplied by winter snows, and now they are soaking up the groundwater, said Merrill.
“Soils will be in decent shape,” at least for a while, said Brian Fuchs, a scientist with the Drought Monitor, which is based at the University of Nebraska-Lincoln. But “the ‘banked’ moisture in the soils will last only so long, as regular precipitation is needed to sustain the demand,” he said.
As to what has been behind the lack of rain, “No particular atmospheric pattern explains the dryness,” said Fuchs.
The weather pattern has been such that the majority of the country has “consistently missed precipitation events over the last few months,” he said. “This happens all the time and in all parts of the country. There is not anything forcing this issue that is an anomaly.”
While droughts have occurred in the Philadelphia area, it’s “tough” for them to last since the region is near so many bodies of water, said Tom Kines, senior meteorologist with AccuWeather Inc.
Said Merrill, “We’re not landlocked.”
The outlook for Sunday and the rain prospects thereafter
The rains are forecast to shutvoff not long after daybreak Sunday, but temperatures might get no higher than the mid-50s, 10 to 15 degrees below normal for the date.
Readings return to seasonal normals during the week, but the Climate Prediction Center says chances favor below-normal temperatures through the first week in May.
On the upside, the rain outlooks for now argue against a worsening of drought conditions. Shower chances are in the weather service forecasts Tuesday through Thursday, and AccuWeather said it expects rainfall to be close to normal in May.
In the short term, if you were hoping to defer some yard work this weekend, the window of opportunity may be open.
