Hurricane Polo Soaks Mexico's Pacific Coast as Nolo Bears Down on Hawaii

Heavy rain from Hurricane Polo is sweeping across Mexico's Pacific coastline, where the storm is expected to hold at Category 5 strength as it brushes past the shore with strong winds. Forecasters warn the downpours could trigger flooding and landslides along the affected stretch.

Far to the west, a separate system is bearing down on Hawaii. Tropical Storm Nolo was stationary just under 300 miles south of the state on Thursday and is expected to track north while strengthening rapidly, according to John Bravender, a warning coordination meteorologist at the National Oceanic and Atmospheric Administration.

"The latest NHC forecast has it becoming a major hurricane as it approaches the state," Bravender said. He noted that Nolo is expected to turn westward again as large-scale steering flows shift, a change that leaves considerable uncertainty over how close the storm will come and how severe the impacts will be.

Nolo is forecast to reach hurricane strength by late Thursday and to near Hawaii's Big Island on Friday night. Maui is also likely to see extremely heavy rain through Saturday.

Rainfall totals on parts of the Big Island could exceed 20 inches, with isolated areas receiving as much as 35 inches, Bravender said. He described the expected volume as catastrophic on its own, but warned that it will fall on ground already saturated by earlier storms.

Between 30 and 40 inches of rain fell during Hurricane Lala, causing widespread damage, and subsequent tropical remnants and moisture from other systems, including Norbert, have kept the soil soaked. Roads washed out in earlier flooding are still being rebuilt, and debris being cleared could be swept away again.

"We're seeing more damage and more impacts from that, even more so," Bravender said of the prospect of another round of extreme rainfall.

Nolo is the seventh tropical cyclone of the Central Pacific season, which typically sees four to five. Bravender said the season was expected to be active, with the Climate Prediction Center projecting five to 13 cyclones, a wide range that hinged on how quickly El Nino would develop. That pattern has strengthened rapidly, pointing to the higher end of the forecast, though still short of the record set in 2015.

Activity would normally taper off at this time of year, but El Nino years tend to bring warmer ocean temperatures and a longer hurricane season. Bravender pointed to Hurricane Eva, which struck Hawaii during Thanksgiving week in 1982, as an example of late-season activity, noting that strong El Nino years have produced storms as late as December and January.

"This could be an ongoing event, not just a busier than normal season, but also a longer than normal season," he said.