WASHINGTON, Aug. 1 (DC Times Online) — The National Hurricane Center’s Aug. 1 Tropical Weather Outlook called for no tropical activity in the Atlantic basin, Caribbean Sea or Gulf of Mexico during the following week. The outlook listed no areas of interest and gave no immediate signal that a tropical depression or storm was likely to form.
For people in the United States, that means there is no storm-specific action to take at this time. Residents should still check the National Hurricane Center’s seven-day outlook during hurricane season and keep basic hurricane plans current, especially along the Southeast and Gulf coasts.
The quiet forecast comes as El Niño strengthens in the Pacific. The climate pattern is now creating conditions that generally make it harder for Atlantic storms to organize, even though parts of the Atlantic remain unusually warm.
Why El Niño matters
El Niño occurs when surface water in the central and eastern tropical Pacific becomes warmer than normal. That warming can change the pattern of winds around the world.
For the Atlantic hurricane basin, the main concern is stronger winds high above the ocean. Those winds can create vertical wind shear, meaning wind speed or direction changes sharply with height. Strong wind shear can tilt or tear apart a developing storm, preventing it from building a well-organized circulation.
The National Oceanic and Atmospheric Administration and its Climate Prediction Center have said El Niño is strengthening. Forecast discussions cited by the FOX Forecast Center said the event could become one of the strongest El Niño episodes observed since 1950. Other reports have described it as potentially near record strength, but the supplied forecasts do not establish a final ranking.
Warm water is not enough
Ocean temperatures are one ingredient that can support tropical development. Warm water provides energy to thunderstorms, and the Atlantic Main Development Region — the area stretching from the west coast of Africa toward the Caribbean — is an important birthplace for many Atlantic storms.
But warm water alone does not guarantee development. The FOX Forecast Center said the warm Atlantic was being offset by El Niño-related wind shear. Saharan dust and dry, stable air were also suppressing thunderstorms across parts of the tropical Atlantic.
Dust from Africa can travel westward over the ocean. The dry air and dust can limit the deep thunderstorms needed for a tropical system to strengthen.
Several tropical waves were moving off the African coast into the Main Development Region as of the latest reports. A tropical wave is a stretched-out area of lower air pressure and unsettled weather. Most waves never become storms. Their chances depend on whether they can find warm water, enough moisture and light enough winds to organize.
A slow start, but not a harmless season
The FOX Forecast Center reported that two named storms had formed by July 31, one in June and one in July. Earlier reports described the season’s total differently, reflecting different reporting cutoffs and storm counts. The National Hurricane Center’s current outlook, however, showed no immediate development.
The Atlantic hurricane season began June 1 and runs through Nov. 30. A slow start does not mean the rest of the season will be quiet. Atlantic activity often increases later in the summer, especially from August through October, when ocean temperatures are higher and conditions can become more favorable.
Seasonal forecasts also differ. NOAA’s outlook, as reported by Fox Weather, called for 8 to 14 named storms, 3 to 6 hurricanes and 1 to 3 major hurricanes. Colorado State University projected 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 reaches 74 mph, while a major hurricane is classified as Category 3 or stronger, with winds of at least 111 mph. These seasonal numbers describe the expected amount of activity across the basin; they do not predict where storms will go or whether one will affect the United States.
What to watch next
The near-term forecast is controlled by the current environment, not by the seasonal average. The National Hurricane Center’s seven-day outlook is the certified source for official development chances and storm advisories.
Residents should watch that outlook for changes, particularly those near the Gulf Coast, Florida and the Southeast coast. At present, the official forecast points to continued quiet conditions through the following week, while forecasters continue to monitor the tropical waves, Saharan dust, ocean temperatures and the strengthening El Niño.
