WASHINGTON, Aug. 1 (DC Times Online) — The National Hurricane Center was forecasting no tropical activity in the Atlantic, Caribbean or Gulf of Mexico through the following week in its Aug. 1 outlook. The immediate step for residents is to keep checking the center’s seven-day Tropical Weather Outlook, even as the basin remains quiet.
The lull comes as El Niño strengthens over the Pacific. The climate pattern is changing winds high above the Atlantic, creating conditions that can tear apart thunderstorms before they organize into tropical storms or hurricanes.
The FOX Forecast Center said two named storms had formed by July 31, one in June and one in July. That pace is behind the more active seasons predicted by several forecasters, although a slow start does not rule out storms later in the season.
Why El Niño matters
El Niño is a recurring climate pattern in which ocean temperatures become warmer than normal in parts of the central and eastern tropical Pacific. Those warmer waters can shift the position and strength of the jet stream and other large-scale winds around the world.
For the Atlantic hurricane basin, the main concern is wind shear. Wind shear means that wind speed or direction changes with height. Tropical systems need a relatively organized column of air to grow. Strong wind shear can tilt or break apart the thunderstorms that surround a developing storm.
NOAA’s Climate Prediction Center has said El Niño is strengthening. Forecast information cited by the FOX Forecast Center indicated that the event could become one of the strongest since records began in 1950, but the supplied forecasts do not establish that it will set an official record.
North Carolina State University’s climate office reported in May that waters in the Atlantic’s Main Development Region were warmer than normal. That warmth can provide energy for storms. But the same analysis said developing El Niño could increase upper-level winds over the tropical Atlantic, offsetting some of the effect of warm water.
What is happening near Africa?
Several tropical waves were moving west from the African coast into the Main Development Region, an area that stretches across the tropical Atlantic toward the Caribbean. Tropical waves are elongated areas of lower air pressure and unsettled weather that can sometimes become tropical depressions or storms.
Their presence does not mean a storm will form. The FOX Forecast Center said development would depend on three main factors: wind shear, Saharan dust and ocean temperatures.
Dust and dry, stable air from the Sahara can reduce the thunderstorms needed for tropical development. The FOX Forecast Center said those conditions were suppressing storms across parts of the tropical Atlantic. The National Hurricane Center outlook also showed no areas of interest and no expected development during the seven-day period covered by the outlook.
The waves could still be watched as they move west. Conditions can change, especially if a system reaches an area with less dry air, weaker wind shear or warmer water.
Does a quiet start mean the season is safe?
No. Seasonal forecasts describe broad patterns, not the exact timing or location of storms. A single hurricane can still affect the United States during a season with below-average activity, and a storm does not need to form far out in the Atlantic to become a concern for the Gulf Coast or Southeast coast.
Forecast groups have also differed in their expectations. NOAA was reported as forecasting 8 to 14 named storms, three to six hurricanes and one to three major hurricanes. Colorado State University’s forecast called for 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.
Those forecasts were made with the understanding that El Niño could suppress activity. The AccuWeather forecast team said a stronger El Niño would increase the likelihood of a less active end to the season.
For now, the official near-term message is limited: the National Hurricane Center expects no tropical development in the Atlantic basin through the seven-day outlook period. People along the Gulf and Southeast coasts can use the quiet period to monitor the center’s daily outlooks and review hurricane plans before conditions become more threatening.