Tropical wind and rainstorm brewing near the Carolina coast to track inland
Conditions are coming together to spur on tropical development near the US coast and unleash coastal flooding and beach erosion as well as the potential for dangerous flooding rainfall.
It was a windy scene in southeastern Virginia on Sunday morning. Aaron Jayjack is in Virginia Beach where a storm is expected to bring heavy rainfall and coastal flooding to the area.
A developing storm off the Carolina coast could evolve, make landfall and potentially stall over land bringing downpours for several days, AccuWeather meteorologists warn.
Early this week, an area of low pressure is expected to gather over warm waters just off the coast, possibly transforming into a tropical depression or tropical storm in the early week. Because of the risks to lives and property, stemming from flooding rain, storm surge and strong winds in a densely populated area of the United States, the AccuWeather RealImpact™ Scale for Hurricanes is a 1 for this storm.
Showers and thunderstorms blossomed in the zone last Thursday. From Thursday to Saturday, easterly breezes created around high pressure to the north agitated seas and surf.
The combination of the lingering high in the Northeast and a strengthening low pressure area off the Carolinas will stiffen winds even further and cause seas and surf to build in the stretch of the Atlantic coast from northeastern Florida to the Delmarva Peninsula this week.
AccuWeather meteorologists began referring to the system as a tropical wind and rainstorm during the middle of last week to help raise public awareness and help officials plan and prepare.
Homegrown development such as this is much more common in the late spring to early summer. Most tropical systems during the heart of the hurricane season develop thousands of miles to the south over the central Atlantic.
The feature is not fully tropical just yet, but some transition will occur this week. Regardless of the official tropical designation by the National Hurricane Center, winds will increase, and powerful surf with frequent and strong rip currents will occur while beach erosion ramps up.
Moderate coastal flooding is anticipated, which will be worse at times of high tide. Some access roads to the barrier islands may be blocked by high water or damaged by erosion. Beachfront homes may be at risk.
Depending on the track and intensity of the tropical wind and rainstorm, coastal flooding may extend north to the upper portions of the Chesapeake and Delaware bays. Water levels will be enhanced by the upcoming full moon early this week.
For a tropical depression to be declared, the system must have a warm core with a defined circulation and sustained winds of 38 miles per hour or less. The same conditions with winds of 39-74 mph designate a tropical storm.
Widespread wind gusts of 40-60 mph into Monday across southeastern Virginia, eastern North Carolina and northeastern South Carolina can cause localized power outages, some tree damage and minor damage to structures.
Along the North Carolina coast, near and to the east of where the storm makes landfall, gusts of 60-70 mph with an AccuWeather Local StormMax™ of 80 mph will cause more widespread power outages.
There may be far more extensive impacts from the homebrew storm.
"A prolonged period of moisture funneling in from both the Gulf of Mexico and the Atlantic Ocean will result in areas of heavy rain with a heightened flood threat across portions of the Southeast ... into [the new] week," AccuWeather Meteorologist Brandon Buckingham said.
As the storm approaches the Carolinas into Monday morning, heavy rain will spread north across southern North Carolina and northern South Carolina. In these areas, widespread rain amounts of 4-8 inches with an AccuWeather Local StormMax™ of 20 inches will cause flash flooding and road closures.
Despite existing dry conditions, where the heaviest rain occurs, it can be enough to trigger flash flooding in urban areas and along small streams and significant rises on some of the rivers. Only because river levels are so low can major flooding be avoided.
Lesser rain amounts of 1-4 inches will occur through the middle of the week across a wide swath of the mid-Atlantic and central Appalachians.
Wide track window possible with homegrown tropical rainstorm after landfall
The exact track and intensity of the homegrown tropical wind and rainstorm will determine which areas receive the most rain. The track of the system depends on how quickly it develops and the strength and position of the high pressure zone over the Northeast states.
Assuming a defined center has formed, a landfall along the northern South Carolina coast on Monday afternoon is most likely.
A track to the north may send heavy rain right up along the mid-Atlantic coast from Tuesday to Thursday. Should this occur, it would break a long string of days with dry weather that began around Sept. 8.
A more westward track might expand the heaviest rain from the Carolina coast to the southern Piedmont and Appalachians early in the week.
At this time, AccuWeather meteorologists believe a blend of the two scenarios is most likely with a northwest track that spreads heavy rain inland mainly from the eastern Carolinas to eastern and central Virginia. Some rain will reach into the dry air farther to the west over North Carolina, Virginia and West Virginia as well as northern Maryland, Pennsylvania, Delaware and New Jersey.
Aside from the potential for torrential rain, dangerous flooding and travel issues, the rain could benefit the hard-hit drought areas of Virginia and West Virginia.
Gordon spins in the Atlantic
Elsewhere in the Atlantic, a tropical depression (Seven) formed earlier last week over the central Atlantic. At midday last Friday, NHC upgraded the depression to Tropical Storm Gordon. Gordon is likely to remain at sea with no threat to land for at least the next week.
Following Gordon, the next name on the list of tropical storms for the 2024 Atlantic hurricane season is Helene.
Looking ahead: Watching the Caribbean, southwest Atlantic
The same jet stream storm that will help pull Atlantic moisture into the southeastern U.S. and part of the mid-Atlantic in the coming days may linger for well over a week.
If this occurs, it will likely mean a continuation of clouds, showers and thunderstorms for the Southeast, but it may also help pull in any new tropical features that crop up.
There is some indication that a new tropical system may develop in the Caribbean or the southwestern Atlantic next weekend. The jet stream storm could draw any system that forms in those regions into the Southeast states, which would further raise flooding concerns, along with a new onslaught of strong coastal winds and problems related to rough surf.
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