Hurricane Rachel is expected to turn toward Mexico and send heavy rain into drought stricken parts of the southwestern United States, potentially easing drought conditions but also increasing the risk of flooding.
As of Tuesday, Rachel was a Category 1 hurricane with maximum sustained winds of 85 mph and was located about 640 miles west southwest of the southern tip of Baja California Sur. The storm was moving west at 8 mph, with its strongest winds and heaviest rain expected to remain offshore initially.
Meteorologists expect a developing dip in the jet stream to steer Rachel toward northwestern Mexico. As the hurricane turns, its moisture could spread northeastward into Arizona and Utah, where additional heavy rainfall may trigger flooding, mudslides and debris flows.
The Southwest has already experienced unusually heavy rainfall. Parts of the region received two to seven times their historical average September rainfall, increasing concerns that further downpours could overwhelm vulnerable areas.
Forecasts indicate that 1 to 4 inches of rain could fall from northwest Mexico across much of Arizona and Utah with isolated areas potentially receiving 4 to 8 inches and a possible maximum of 12 inches.
The rainfall could also provide a major boost to the drought stricken Colorado River basin. Water levels in Lakes Powell and Mead reached historic lows during the summer, and additional precipitation in the Great Basin could provide some relief to the watershed.
However, the storm is also expected to generate large swells and dangerous surf along parts of northwestern Mexico and California through the weekend. Recent Pacific storms have already contributed to beach erosion and coastal flooding in California.
Rachel is part of an unusually active eastern and central Pacific hurricane season, which has been influenced by strong El Niño conditions. Forecasters are also monitoring another storm system off southern Mexico that could develop into a major hurricane and bring additional flooding, strong winds and storm surge to western Mexico.