Tropical depression likely to form this week, 90% chance for development. What's St. Johns' forecast?

Last week was, Debby, will this week be Ernesto?

Seven days after Debby's first landfall as a hurricane in Florida, then a second landfall as a tropical storm in South Carolina, the National Hurricane Center released its last advisory on Debby on Aug. 9. The storm brought historic rainfall from Florida to the Carolinas.

A week later, experts say to keep an eye on the tropics.

The National Hurricane Center is tracking a tropical wave that has a high formation for development. If it does become a named storm, it will be Ernesto.

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Tropical Storm Debby made its second landfall just before 2 a.m. Thursday, Aug. 8, near Bulls Bay, South Carolina. Sustained winds were 50 mph.

Debby's first landfall was as a hurricane in Steinhatchee, Florida, around 7 a.m. Monday, Aug. 5. Sustained winds were 80 mph.

Here's the latest update from the National Hurricane Center in Miami as of 8 a.m. Aug. 11:

Near the Lesser and Greater Antilles (AL98):

Showers and thunderstorms continue to show some signs of organization in association with a broad area of low pressure located about 1000 miles east of the Lesser Antilles. Environmental conditions appear conducive for gradual development of this system, and a tropical depression is likely to form within the next couple of days while the system approaches and then moves near or over the Leeward Islands. Interests on these islands should continue to monitor the progress of this system, and watches or warnings could be required for portions of the area as soon as later today. The system could approach portions of the Greater Antilles by the middle of the week.

  • Formation chance through 48 hours is high at 70 percent.

  • Formation chance through 7 days is high at 90 percent.

Colorado State University predicts 85% chance for hurricane activity through Aug. 19

Atlantic named storm formations from Aug. 6-19 from 1966–2023 and the maximum intensity the named storms reached.
Atlantic named storm formations from Aug. 6-19 from 1966–2023 and the maximum intensity the named storms reached.

CSU forecasters predict there is an 85% chance for hurricane activity from Aug. 6 through Aug. 19.

"The primary threat formation area for major hurricanes in early- to mid-August is in the tropical Atlantic east of the Lesser Antilles."

The next two-week forecast will be released Aug. 20 for Aug. 20-Sept. 2.

On Aug. 6, CSU updated its seasonal forecast for the 2024 Atlantic hurricane season, reducing the predicted number of named storms from 25 to 23 but maintaining its forecast for 12 hurricane and six major hurricanes.

What do the colored areas on the NOAA map mean?

The hatched areas on a tropical outlook map indicate "areas where a tropical cyclone — which could be a tropical depression, tropical storm or hurricane — could develop," said National Hurricane Center Deputy Director Jamie Rhome.

The colors make it visibly clear how likely a system could develop with yellow being low, orange medium and red high.

The National Hurricane Center generally doesn't issue tropical advisories until a there is a named storm, but there is an exception.

"If a system is near land and there is potential for development, the National Hurricane Center won't wait before it issues advisories, even if the system hasn't become an actual storm. This gives residents time to prepare," Rhome said.

Who is likely to be impacted?

It's too early at this time to determine if there will be any impact to Florida or the U.S. from the tropical wave in the Atlantic.

Forecasters urge all residents to continue monitoring the tropics and to always be prepared. That advice is particularly important for what is expected to be a very active hurricane season.

NOAA updates 2024 hurricane season forecast

NOAA updated its 2024 Atlantic hurricane season forecast on Aug. 8, 2024.
NOAA updated its 2024 Atlantic hurricane season forecast on Aug. 8, 2024.

NOAA has updated its prediction for the 2024 Atlantic hurricane season, more than two months and four named storms after its first prediction was released in May.

This season could "rank among the busiest on record," NOAA announced Aug. 8, while updating its prediction on the number of named storms slightly lower but increasing the chance for an above-normal season to 90%.

Here's the latest forecast:

  • Named storms: 17-24

  • Hurricanes: 8-13

  • Major hurricanes: 4-7

  • Above normal season: 90%

  • Near normal season: 10%

Weather watches and warnings issued in Florida

St. Johns County forecast for next few days

St. Johns County is among several northeast Florida counties under a heat advisory for Sunday.

Sunday: A 40 percent chance of showers and thunderstorms, mainly after 11 a.m. Partly sunny, with a high near 94. Heat index values as high as 109. Light southwest wind increasing to 5 to 9 mph in the morning.

Sunday night: A 40 percent chance of showers and thunderstorms, mainly before 10 p.m. Mostly cloudy, with a low around 77. South wind around 6 mph becoming calm after midnight.

Monday: A 30 percent chance of showers and thunderstorms. Mostly sunny, with a high near 94. Heat index values as high as 105. Southwest wind around 6 mph.

Monday Night: A 30 percent chance of showers and thunderstorms, mainly before 8 p.m. Partly cloudy, with a low around 77. Southwest wind 3 to 7 mph.

Tuesday: A 40 percent chance of showers and thunderstorms after 2 p.m. Sunny and hot, with a high near 96. Southwest wind 3 to 6 mph.

Tuesday Night: A 30 percent chance of showers and thunderstorms before 8 p.m. Partly cloudy, with a low around 77.

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When is the Atlantic hurricane season?

The Atlantic hurricane season runs from June 1 through Nov. 30.

When is the peak of hurricane season?

Hurricane season's ultimate peak is Sept. 10 but the season goes through Nov. 30. Credit: NOAA
Hurricane season's ultimate peak is Sept. 10 but the season goes through Nov. 30. Credit: NOAA

The peak of the season is Sept. 10, with the most activity happening between mid-August and mid-October, according to the Hurricane Center.

National Hurricane Center map: What are forecasters watching now?

Systems currently being monitored by the National Hurricane Center include:

Interactive map: Hurricanes, tropical storms that have passed near your city

Excessive rainfall forecast

What's next?

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This article originally appeared on The Ledger: Tropical depression likely in Atlantic. What's St. Johns' forecast?