ORLANDO, Fla. — The National Hurricane Center improved the odds of a newly formed tropical wave to a 70% chance of becoming the next tropical depression or storm of the season. Meanwhile, meteorologists are watching a second tropical wave in the mid-Atlantic moving in the direction of the United States.
First, a tropical wave over the Guinea Highlands in Africa is producing thunderstorms Thursday morning, the NHC said in its 2 p.m. EDT update. Hurricane specialists are expecting the wave to push off the coasts of Senegal, The Gambia and Guinea-Bissau later tonight.
Atlantic conditions are somewhat ripe for development, the NHC said. When the wave first emerged Thursday morning models suggested it had a 60% developing, but meteorologists have since bumped that up to a 70% of developing over the eastern Atlantic next week, and a 40% chance of doing so over the weekend.
Next, another tropical wave in the mid-Atlantic is stirring up some trouble and producing a broad area of disorganized showers and thunderstorms. Conditions east of the Lesser Antilles are expected to be marginally agreeable for development by early next week. Models give the wave a 20% chance of becoming a tropical depression or storm in the next five days.
If either system develops, the first one to do so will be the sixth named storm of the season and don the moniker of Fred. If they both develop, the slower will be named Grace.
The areas of interest are about two weeks shy of the “peak of hurricane season,” or the period where meteorologists observe the most tropical storm and hurricane activity in the Atlantic. Conditions of warm water and low vertical wind shear in the upper atmosphere become ideal for storm production between mid-August and mid-October.
Colorado State University came out Thursday with a sub-season forecast predicting above-normal hurricane activity for the next two weeks. CSU listed warmer-than-usual sea-surface temperatures as the reason why.
“Caribbean is now warmer than normal, while tropical Atlantic (sea-surface temperatures) have also anomalously warmed,” said CSU meteorologist Philip Klotzbach. “Current (sea-surface temperatures) pattern fairly, closely resembles August active Atlantic hurricane season pattern,” which notably can be quite warm.
The National Oceanic and Atmospheric Administration expect the remainder of the 2021 season to be a bumpy one, according to its midseason forecast. A typical season has 13 named storms and seven named hurricanes. On Wednesday, the NOAA updated its forecast predicting 15-21 named storms with sustained winds of 39 mph or greater, seven to 10 hurricanes, and three to five major hurricanes, or storms of Category 3 winds and higher.
The NOAA predicted 13-20 named storms in May, with six to 10 becoming hurricanes and three to five major hurricanes.
Last year, the NOAA made a similar forecast at midseason. By Nov. 30, the end of hurricane season, meteorologists cataloged 30 named storms — the most recorded in a single year.
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