Significant storms on both coasts bring tidal flooding and beach erosion in the East and heavy mountain snow in the Sierra
Also, rain and flooding in southwest Colorado
In brief: There have been no big changes to the coastal storm forecast on the East Coast, with major tidal flooding and beach erosion expected from northeast North Carolina up into Long Island today and tomorrow. The next Atlantic system is not a land concern. Heavy rain in the Southwest did lead to significant flooding in southwest Colorado, with more rain on the way. And the West Coast will see an early season winter storm this week, with a couple feet of snow in the Sierra and beneficial rain across much of California.
Major coastal storm
In general, not a whole heck of a lot has changed since yesterday in terms of forecast impacts for the Mid-Atlantic coast between North Carolina and New Jersey. Starting in Atlantic City, three consecutive 8 foot high tides are expected on the beachfront today and tomorrow.
Atlantic City has only exceeded 8 foot tide levels 8 previous times (last with Sandy in 2012 at 8.8 feet). So to get close 3 straight cycles would be impressive. You have to consider not just the level of the tide, but the compound risk of multiple significant high tides. Coastal flooding will be firmly moderate to perhaps major at times through tomorrow.
Moderate to major coastal flooding will continue up and down the coast from Duck, NC through Long Island into tomorrow. Inundation mapping for the New York City metro is available through the NWS NYC forecast office here.
In addition, rough seas, significant to major beach erosion, and strong winds will continue as well. Wind gusts of 45 to 55 mph and perhaps near 60 mph will be possible on the coastline.
Gusty winds will extend into the NYC area, east across Long Island, strongest near Montauk. Gusty winds will continue into Monday, though today should be the worst.
Rain totals have backed off a little bit, with 1 to 3 inches now expected from Jersey into southern New England, highest in southeast Massachusetts and near the Cape. Upwards of perhaps 3 to 4 inches will be possible there.
The whole system will slowly drift east tomorrow and Tuesday, but it will linger hundreds of miles offshore. This could keep surf high and tides slightly elevated well into this coming week.
Overall, a big time nor’easter for October and still looking like the biggest one since 2016 for Jersey and Delaware.
Tropical Atlantic
Jerry is now technically off the board, but we’ve got a 50 percent area showing up farther out in the Atlantic. This is Invest 97L, and it is no threat to land. However, there is an increasing chance that this is going to eventually acquire the name Lorenzo.
Outside of that, it looks free and clear the next 7 days. Where do we watch heading into the tail end of October? Well, the areas are pretty clear: the southern Gulf, northwest Caribbean, and southwest Atlantic.
Generally, most storms will either meander or eventually quickly turn north or northeast. For now, we’ve got nothing on the radar, but we want to give you an idea of where to look as hurricane season approaches the finish line.
Desert Southwest flooding
Parts of Pagosa Springs, CO were evacuated due to flooding on the San Juan River, which hit major flood stage overnight. The crest of 12.66 feet appears to be highest at this location since 1927.
Total rainfall over the last 2 days has been on the order of 2 to 4 inches with even higher amounts in some of the mountains in southwest Colorado. While this rain is certainly beneficial to the overall water supply in the Southwest, it surely can come with some pain in the short-term.
Rain today will focus mainly on southern Arizona, while another round of rain and storms is expected to the north on Monday, with perhaps another 1 to 2 inches of rain possible in southwest Colorado.
West Coast storm
As noted yesterday, an early season winter storm will pound California early this week. Snow levels should be at or above 6,000 feet, where as much as 1 to 3 feet is possible in the Sierra, mainly south of Highway 50. Storm duration will go from tomorrow into Wednesday.
Snow will also occur farther north in the mountains of Montana and northern Idaho, as well as in parts of Washington and Oregon.
It does appear that this storm will also extend a bit farther south now, to include the LA Basin. Rain totals of 1 to 3 inches in the mountains and perhaps up to an inch in valley locations. No significant flash flooding is expected from this storm, but there will likely be some minor issues due to ponding, travel disruption, and potentially some minor debris flow concerns in burn scar areas. No flood watches are currently posted. Either way, there is no denying that this is a good sign to get some snowpack and rain early in the season, especially in what is expected to be a La Niña winter, where southern California historically leans a bit drier (not a guarantee).
The weather should calm down nationally after midweek.
Meanwhile villages in Alaska are being swept away by a typhoon and there is very little news about it. These people can’t just hop in their car and evacuate, because there are no roads to western Alaska.