Unusual Humidity Grips Southern California: What’s Going On?
Residents of Southern California are experiencing an unusual bout of mugginess not typically associated with the region’s summer climate. For almost a month, the area has been enveloped in persistent humidity, with forecasts suggesting little respite in the near future. Despite the discomfort, this increase in moisture isn’t expected to result in significant rainfall.
Normally, Southern California’s dew point hovers around 60 degrees during this time of year. However, a recent reading in downtown Los Angeles saw the dew point climb to nearly 70 degrees. This level of humidity is considered uncomfortable during summer months, according to meteorologists.
“We do get these prolonged periods of heat, but what is unusual is the humidity,” explained Bryan Lewis, a meteorologist with the National Weather Service.
The Role of Pacific Storms
Atmospheric conditions, primarily involving storms and ocean temperatures, are driving the current humidity levels. Tropical storms traveling across the Pacific have been a significant factor. Tropical Storm Fausto and Hurricane Genevieve, both originating near Central America, have contributed moisture to the region.
While Fausto briefly intensified to a Category 2 hurricane, its strength diminished as it moved past Hawaii. Meanwhile, Genevieve reached Category 5 status but is not expected to bring a substantial amount of moisture to Southern California compared to other recent storms.
Weather patterns closer to home, such as a high-pressure system over the Western U.S. and the North American monsoon, are also channeling tropical moisture into the area.
Impact of Warming Oceans
Alongside storms, elevated ocean temperatures are playing a critical role in the region’s humidity. Warmer oceans cause increased evaporation, sending more moisture into the air, which is then carried inland by winds.
Southern California has experienced a series of marine heatwaves over the past decade, often dissipating in winter. However, the current heatwave has persisted for over a year, with scientists attributing its severity to human-induced climate change.
Although Hurricane Genevieve is expected to have a limited impact on moisture levels, relief may come as drier air from the northwest is forecasted to reduce humidity, particularly inland. Coastal areas, however, might continue to experience elevated humidity due to warmer ocean temperatures.
Original Story at laist.com