Tuesday, July 16, 2024

Area winter forecasts call for temperature swings

Blooming roses at the New Hanover County Arboretum. Photo by Hannah Leyva.
Blooming roses at the New Hanover County Arboretum. Photo by Hannah Leyva.

“It looks like there’s a rollercoaster ahead of us.”

That’s how Steve Pfaff, the warning coordination meteorologist at the National Weather Service in Wilmington, describes the long-range temperature predictions for the Cape Fear region over the next few months.

After a spell of above-average temperatures in December, locals were shocked back into reality, with lows in the 20s and 30s earlier this week. While Pfaff said it has been quite cold, with some flurries even reported in the area a few days ago, it hasn’t been too far from normal.

“It’s been cold but not anomalously so,” Pfaff said. “We’ve just been used to the warmer-than-normal temperatures we had at the end of last month, so we’re still getting acclimated.”

According to Pfaff, the average high temperatures around this time of the year is in the mid-50s with the average low in the mid-30s. The long-term outlook for the months of January, February and March call for “near normal” temperatures, but the meteorologist said that could mean different things.

“Based on these predictions, it is hard to tell how far above or below normal those numbers could be,” Pfaff said. “We’re in for some mood swings with the temperatures ahead.”

The fluctuations have had an effect on plants in the area. December’s warmth tricked some flowers into showing up before expected.

“We already have some spring azaleas and some Lady Banks’ roses in bloom,” said Scott Childs, grounds supervisor at Airlie Gardens. “It’s way too early for them.”

Childs said that buds that have already grown can get “burned” by cold snaps, and flowers that have already blossomed, especially those that are white, turn brown. Susan Brown of the North Carolina State University Extension Service and Arboretum, which is run by New Hanover County, said this is also affecting perennials and other flowers that have yet to go dormant for the winter.

“When we start getting consecutive nights below 32 degrees, all that foliage is going to be damaged and it’s going to look bad,” said Brown, who added that she does not think the flowers blooming now will have problems in the spring. “But it’s not going to kill the plant, because the root system will still be alive.”

Other plants, particularly bulbs like tulips that are planted in the winter, need to lie dormant in cold ground in order to produce the best blossoms.

“A lot of plants require a certain number of chilling hours to bloom properly,” said Childs, citing it as the reason tulips are year-round in places further north but need to be re-planted each year in the South. “If they don’t have an extended period of cold weather, it can affect their spring blooms.”

The lack of long periods of cold temperatures can also affect fruit trees, according to Brown.

“We have to have a certain number of chilling hours for certain fruit trees to break dormancy and then create fruit,” Brown said. “We usually are at about 800 to 900 chilling hours normally, but we’re so low right now that people who have varieties that are on that cusp, like apples, may not get fruit in the spring.”

The ups and downs are a result of different jet stream patterns that have been affected by the El Nino event occurring in the Pacific Ocean. The Arctic jet stream has kept the cold air well to the north so far this winter, resulting in December’s mild temperatures.

“The coldest air’s kind of bottled up there,” said Pfaff. “It hasn’t really been able to find a path down to us yet.”

The subtropical or southern jet stream, which runs from the Pacific across Mexico to the southern United States, has been active, bringing extra moisture and causing high water levels. While heavy rainfall has not yet been a factor in this new year, predictions indicate it could be a very wet winter, and Pfaff said the area is still in danger of flood problems due to lingering saturation from last year’s historic rain events.

“Think of the ground as a sponge that has soaked up all the water it can take,” explained Pfaff, who said 2015 was the second wettest year on record for Wilmington. “People that live along rivers and waterways need to be extra cautious because of the conditions that are in place.”

That extra moisture has been bad news for grass in the area. According to Childs, turf needs time to set, and the amount of rain the region has received recently has hindered that process.

“We’ve seen lots of turf disease,” said Childs, saying it was especially bad for their zoysia grass, a hardy, drought-tolerant species that is used for lawns in many parts of the country. “We’ve found a lot of fungal bacteria there.”

At the county arboretum, Brown said she and her staff over-seeded their rye grass, which she thinks may be the reason they have not had problems with disease, but some others, including herself, have had problems with their own lawns.

“If you look at my zoysia grass, it’s a patchwork of brown and green spots,” Brown said. “You’re seeing a lot of unusual activity because they just don’t know what to do.”

Though it’s hard to tell exactly how plants will react to all the temperature changes, Pfaff said more weather like this week’s “mood swings” can be expected in the immediate future. A mild weekend, for example, will be followed by well-below-normal temperatures later next week with a chance for rain every few days.

“We haven’t been able to stay put [temperature-wise],” Pfaff said. “It’s going to be a bit of a rollercoaster ride this winter.”

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