Due to this year’s strong El Niño season, representatives from the National Weather Service (NWS) in Wilmington believe this winter could see the highest precipitation totals in decades, rivaling some of the strongest events in recent history and creating a high potential for river flooding.
According to Tim Armstrong, senior meteorologist and climate program leader for the Wilmington NWS, “While El Niño typically reduces the severity of our hurricane season due to increased wind shear across the tropical Atlantic and Caribbean, its largest local impacts are noted during the winter with heavier precipitation typically occurring across the southern United States including the Carolinas.”
So, what produces this heavy rain?
Huge thunderstorm clusters form over the unusually warm tropical eastern Pacific, which lift tremendous amounts of moisture into the atmosphere. Powerful subtropical jet streams—frequently observed during El Nino winters—efficiently transport this moisture across the southwest to eastern United States where it falls as rain, according to Armstrong.
NWS officials identified a powerful subtropical jet stream as the source of a below-normal hurricane season prediction in early August— and believe it could become similar to a weather pattern created during the strong El Niño season from December, 1997-February, 1998.
During those months, rainfall totals doubled from a winter season average of 11 inches of rain, to 23 inches with some of the highest river crests ever observed occurring on the Cape Fear River at William O. Huske Lock and Dam, on the Little Pee Dee River at Gallivant’s Ferry, and on the Black River at Kingstree, SC.
The average rainstorm usually accounts for fractions of an inch of rain, but storms during a strong El Niño season can bring extreme amounts very quickly. Specific instances of high precipitation— or what the NWS refer to as “anomalies”— included storms on January 6-8, 1998, which brought two inches of rain and on January 23, 1998, which dumped a whopping three inches of rain in one day, almost exceeding the normal seasonal average for the entire month.
While the winter season is still months away, for now NWS officials continue to monitor and update the potential impact of El Niño.
If you would like to learn more about the effect on our local climate, you can learn more on the NWS website located here.
James Mieczkowski is a news reporter for Port City Daily. He can be reached at firstname.lastname@example.org On Twitter: @mieczkowskiPCD