WASHINGTON, Aug. 1 (DC Times Online) — The National Hurricane Center’s Aug. 1 outlook forecast no tropical activity in the Atlantic basin, Caribbean Sea or Gulf of Mexico during the following week. For residents of the United States, the practical step is to keep checking the center’s official Tropical Weather Outlook rather than treating a quiet start as a guarantee that the rest of the season will be quiet.
The Atlantic hurricane season began June 1. As of July 31, the FOX Forecast Center said two named storms had formed, one in June and one in July. That pace was below several seasonal forecasts, but it does not determine how active the full season will be.
Why El Niño matters
El Niño is a recurring climate pattern in which unusually warm water develops in the central and eastern tropical Pacific Ocean. It can change the pattern of winds high above the Atlantic.
Those changes can produce stronger upper-level winds over developing tropical systems. The difference in wind speed or direction between the lower and upper atmosphere is called wind shear. Strong wind shear can tilt or tear apart a storm’s circulation, making it harder for thunderstorms to organize.
NOAA’s Climate Prediction Center has described El Niño as strengthening. Forecast assessments cited by NOAA and other forecasters suggested the event could become one of the strongest since modern records began, although the supplied official materials do not establish a final ranking or a record-setting outcome.
North Carolina State University’s climate office reported in May that the Atlantic’s Main Development Region — the area between the African coast and the Caribbean where many Atlantic storms form — had warmer-than-normal water. Those warm waters can provide energy for storms. But the climate office also noted that a developing El Niño could increase upper-level winds over the tropical Atlantic.
In other words, warm ocean water is one ingredient for hurricane development, but it is not the only one. At present, El Niño-related wind shear is offsetting some of the support provided by warm water.
What is happening near Africa?
Several tropical waves were moving west from the African coast into the Main Development Region. Tropical waves are areas of disturbed weather that can sometimes develop into tropical depressions, storms or hurricanes.
The FOX Forecast Center said those waves still faced several obstacles: hostile winds, dry air and Saharan dust. Dust and dry, stable air can reduce the thunderstorms needed to build a storm’s circulation. Ocean temperatures, wind shear and the amount of moisture around each wave will help determine whether any of them can organize.
The National Hurricane Center’s seven-day outlook issued around Aug. 1 showed no areas of interest and no expected tropical activity in the Atlantic, Caribbean or Gulf during that period. That outlook covers the near term; it does not rule out development later in August or during the rest of the hurricane season.
Does a slow start mean a safe season?
No. Seasonal forecasts describe broad patterns, not a schedule for individual storms. A season can begin quietly and become more active later if wind patterns, ocean temperatures and moisture conditions change.
Forecast groups also differed in their estimates. NOAA was reported as forecasting 8 to 14 named storms, three to six hurricanes and one to three major hurricanes. Colorado State University forecast 11 named storms, five hurricanes and two major hurricanes. AccuWeather forecast 8 to 14 named storms, four to seven hurricanes and two to four major hurricanes.
A named storm has sustained winds of at least 39 mph. A hurricane has sustained winds of at least 74 mph. A major hurricane is one rated Category 3 or higher, with sustained winds of at least 111 mph.
The forecasts were made before the full season had unfolded and can change as atmospheric and ocean conditions evolve. The number of storms also does not measure the danger to a particular community. One storm making landfall in a populated area can cause serious damage, even in a season with relatively few storms.
What should U.S. residents do now?
There is no specific storm-related action called for by the Aug. 1 National Hurricane Center outlook. Residents in hurricane-prone areas can use the quiet period to review evacuation routes, check emergency supplies and confirm how they will receive warnings.
The most reliable near-term source for new tropical threats is the National Hurricane Center’s Tropical Weather Outlook. Residents along the Gulf Coast, the Southeast coast and other Atlantic coastal areas should rely on local emergency managers and official forecasts if a system later develops.
For now, the forecast points to a suppressed Atlantic pattern driven by El Niño, wind shear, Saharan dust and dry air. Those conditions may limit development in the short term, but they are not a guarantee that the season will remain inactive.
