The tropics threw a curveball at forecasters late Aug. 11.
A tropical wave east of Bermuda that had a low chance of development just a day ago has now strengthened into Tropical Storm Cristobal, according to the National Hurricane Center.
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Farther south, a tropical wave "is likely" to become a tropical depression over the next couple of days. It's has been designated as Invest 92L.
While this season is expected to see below-normal activity due to the presence of a strong El Nin?o, forecasters have been warning North Carolina residents should always be prepared.
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Here's what you should know based on the latest advisory from the National Hurricane Center as of 8 a.m., Aug. 12.
Invest 92L likely to become tropical depression in next day or two
Special note on the NHC cone: The forecast track shows the most likely path of the center of the storm. It does not illustrate the full width of the storm or its impacts, and the center of the storm could travel outside the cone. In 2026, the Hurricane Center will experiment with a new cone to include 90% of forecast track possibilities instead of the previous 67% forecast error.
? Track Invest 92L
An area of showers and thunderstorms associated with a tropical wave is located about 900 miles west-southwest of the Cabo Verde Islands.
Environmental conditions are forecast to be conducive for development during the next couple of days, and a tropicaldepression will likely form while the system moves westward to west-northwestward across the central tropical Atlantic.
Spaghetti models for Invest 92L
Special note about spaghetti models: Illustrations include an array of forecast tools and models, and not all are created equal. The Hurricane Center uses only the top four or five highest performing models to help make its forecasts.
Spaghetti models for Tropical Storm Cristobal
Special note about spaghetti models: Illustrations include an array of forecast tools and models, and not all are created equal. The Hurricane Center uses only the top four or five highest performing models to help make its forecasts.
What is an invest?
Short for investigation, the National Hurricane Center uses the term invest for areas of low pressure it is monitoring for potential development into a tropical depression or storm.
Invests are not tropical depressions or tropical storms. They're usually clusters of showers and thunderstorms, and just because they've been designated as an invest does not guarantee they'll strengthen into a tropical storm or hurricane.
Invests run from 90 to 99, followed by a letter: L for the Atlantic basin and E for those in the eastern Pacific. After 99, it starts over again and the next invest would be 90.
Once something has been designated as an invest, specialized data sets and computer models can begin, including scheduling Hurricane Hunter aircraft missions and running spaghetti models.
Is there a hurricane coming toward North Carolina?
It's too early to determine what, if any, impacts from any of the tropical waves in the Atlantic could be felt in North Carolina, the National Weather Service cautioned residents to monitor the tropics and to stay prepared.
"The storm would have to thread the needle in order to reach the Southeast coast of the United States sometime late next week," according to AccuWeather.
"The storm would have to stay organized and strong enough to survive extensive wind shear over the Caribbean. But if it gets too strong before reaching U.S mainland waters, it will turn north and track well east of the East Coast."
Could tropical waves impact North Carolina?
There is a high risk of tropical development in the open Atlantic Aug. 12-15, according to Alex DaSilva, AccuWeather lead hurricane expert via email Aug. 10.
"Right now, this area is in a mostly favorable environment for development. Wind shear near this tropical wave is light, however some dry air will prevent any rapid organization.
"This wave has a high chance to develop into a tropical depression or storm during the middle or latter portions of this week.
"As the tropical wave approaches the northern Lesser Antilles late this weekend into early next week, it will begin to encounter more wind shear which should help to limit strengthening. It is also possible that the wave will completely get ripped apart by the shear near the islands.
"The stronger the wave becomes, the more likely it is to move north and away from the Lesser Antilles. If this happens, the storm would likely move north into the open Atlantic and not impact the U.S.
"If the wave stays weaker, there is the chance it could move a little closer to the Southeast coast, however it would have to get through a wall of wind shear which would likely substantially disrupt the storm. If this would approach the U.S. it wouldn't be until mid to late next week, so we have plenty of time to watch it."
The tropical wave east of Bermuda is not expected to impact North Carolina or the U.S., according to AccuWeather.
National Hurricane Center tracking 3 disturbances in Atlantic basin
Besides the invests, the National Hurricane Center is also tracking an area of low pressure in the eastern Atlantic:
Eastern Tropical Atlantic: A tropical wave just offshore of the coast of west Africa is producing disorganized showers and thunderstorms.
Environmental conditions are forecast to be generally conducive for some development of this system during the next several days while it moves westward or west-northwestward across the eastern and central tropical Atlantic.
What is a disturbance?
The National Hurricane Center's tropical outlook map highlights "disturbances" in the Atlantic basin.
These are clusters of storms with some organization, but which don't have a defined circulation typical of tropical cyclones.
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If shown on the tropical outlook map in orange or red, forecasters are predicting the potential of those disturbances into developing as medium or high, respectively.
Disturbances shown on the map with a gray x have little to no chance for development. This is a change from prior years which indicated such disturbances in yellow.
What is a tropical wave?
"Tropical waves are clusters of showers and thunderstorms that act as the seedlings for many tropical storms throughout the Atlantic season," said Alex DaSilva, AccuWeather lead hurricane expert, via email.
“There are about 60 tropical waves that move across the Atlantic each year, and roughly 10 percent to 15 percent of them develop into a tropical system. That’s about one in seven.
"Tropical waves are important because they contribute to about 80 percent of all major hurricanes."
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