MOBILE, Ala. — The Atlantic hurricane season is entering the stretch of the calendar when it typically ramps up, yet the basin is currently calm. Forecasters point to an unusually strong, early-arriving El Niño pattern as the main reason storm activity has stayed suppressed even as the season’s climatological engine starts to rev up.
The Calendar Says It’s Time to Get Active
Mid-August traditionally marks the beginning of the most active phase of the Atlantic tropical season. Activity typically builds from here, peaking between Sept. 10 and Sept. 13, and continuing at an elevated level through October. For coastal Alabama and the broader Gulf Coast, this stretch of the calendar is historically the period requiring the closest attention.
Despite that timing, the Atlantic basin is currently completely quiet. That’s a notable turn, given that the basin saw active tropical waves and even a tropical storm just last week. The sudden lull, arriving right as the season should be gaining momentum, has been the focus of forecasters trying to explain what’s holding development in check.
Wind Shear Is Doing the Heavy Lifting
The primary culprit behind the quiet stretch is hostile upper-level wind shear. Strong shear is currently spread across the Atlantic, the northern Caribbean and the Gulf, actively working against the kind of storm organization needed for tropical development. Wind shear, the change in wind speed and direction with height, can tear apart a budding storm’s structure before it has a chance to strengthen, and right now it is widespread across the exact areas where storms would otherwise be expected to form.
That hostile wind pattern isn’t happening in isolation. Forecasters say it is being driven by an El Niño event that developed well ahead of its usual schedule this year. Water temperatures associated with the pattern are approaching 2 degrees Celsius above normal, a threshold that qualifies as what forecasters call a “super El Niño.” El Niño patterns are known to alter atmospheric circulation in ways that increase wind shear over the Atlantic, and this year’s early and unusually strong version appears to be doing exactly that.
What It Means for the Rest of the Season
Because of the hostile environment El Niño has created, both the National Oceanic and Atmospheric Administration and Colorado State University are forecasting a below-normal number of named storms for this year’s season. Both organizations base their seasonal outlooks in part on large-scale patterns like El Niño, which has a well-documented history of tamping down Atlantic hurricane activity by increasing shear across the basin.
Still, a below-normal forecast is not the same as an inactive one. The season’s historical peak, in mid-September, is still ahead, and conditions in the tropics can shift as the season progresses. For now, though, the combination of an early, strong El Niño and the wind shear it has generated across the Atlantic, Caribbean and Gulf is keeping the basin quiet at a time of year when it would typically be waking up.