How the Jet Stream Ended Morocco's Seven-Year Drought — and Why El Nino's Effect Is Unclear

Morocco spent most of the last decade drying out. Between 2019 and 2024 the country recorded six consecutive years of below-average rainfall, the longest such stretch on record, and the 2023-24 hydrological year was its driest in more than six decades, with a national total of just 106.4 millimeters. Per capita renewable water availability had fallen to about 620 cubic meters a year, and three decades of overuse had reduced water levels in several aquifers.

Then, in the winter of 2025-26, rain returned suddenly and on a scale Morocco had not seen in a generation. Seven years of drought ended in a single winter. Severely depleted reservoirs began filling rapidly, and rivers that had run dry started flowing again.

Researchers tracing the shift point to the North Atlantic. Most of Morocco's winter rain arrives on Atlantic storms steered by the North Atlantic Oscillation, the pressure difference between the Azores and Iceland that controls the jet stream, the high-altitude current carrying weather systems. Through the winter, pressure fell near the Azores and rose near Iceland, weakening that gradient and pushing the jet stream's fastest core south toward the Moroccan coast. Storm after storm arrived from the Atlantic, and the Rif and Atlas mountains forced the moist air upward, producing especially heavy rain over the Sebou basin in the northeast.

A record-breaking El Nino is developing in the Pacific, and the U.S. National Oceanic and Atmospheric Administration puts the odds of a very strong event this winter above 90%. Whether that brings Morocco another wet winter or a return to drought cannot yet be answered, researchers say: strong El Nino winters can push the North Atlantic Oscillation negative late in the season, sending storms south, but the signal reaches the Atlantic inconsistently, competing with the North Atlantic's own internal variability.

During the strong El Nino of 2023-24, forecasters expected the North Atlantic Oscillation to shift into its negative phase. It never did.