Atmospheric Rivers and Rising Rivers: Weather Insights for the Pacific Northwest

The primary focus of today's briefing is the significant and ongoing impact of a substantial fall storm across the Northeast, resulting in localized roadway and coastal flooding. As we navigate through the details of this weather event, it becomes evident that gradual improvement is anticipated later in the day. Furthermore, we must acknowledge the impending arrival of the first in a series of Pacific atmospheric rivers that is expected to affect Washington and Oregon, bringing with it rising rivers and hazardous surf conditions. Additional warnings are in effect for various coastal regions, including gale warnings and high surf advisories, as Hurricane Melissa remains situated offshore while indirectly contributing to dangerous conditions along the U.S. East Coast. It is imperative that we remain vigilant and heed advisories throughout this tumultuous weather period.On this day, the weather across the United States exhibits a multitude of phenomena, particularly a severe fall storm that is notably impacting the Northeast region. The storm has engendered localized roadway flooding and minor coastal flooding, although it is anticipated that conditions will gradually improve throughout the day. In the western territories, a significant atmospheric river is set to arrive, impacting Washington and Oregon, bringing with it rising river levels, substantial snowfall in higher elevations, and hazardous surf conditions that could endanger coastal and marine activities. Furthermore, Hurricane Melissa, while currently positioned offshore, is generating long-period swells that will reach parts of the East Coast, creating hazardous surf and rip currents that could pose threats to public safety.As we assess the specific regional forecasts, it is evident that Southern California beaches face considerable dangers due to hazardous surf and strong rip currents, as indicated by advisories from the Los Angeles Oxnard Forecast Office. The National Weather Service (NWS) Gray has also issued gale and storm warnings for the coastal waters of Maine and New Hampshire, where strong winds and rough seas are anticipated. Massachusetts continues to experience marine hazards, while New Jersey is under a coastal flood advisory, highlighting the potential for minor inundation around high tide. The New York City Metro area and the Lower Hudson Valley are similarly under wind advisories, indicating the likelihood of gusts that could cause damage and complicate travel. In Oregon, a dual concern arises with hazardous marine conditions and a strengthening atmospheric river, prompting advisories regarding high surf and potential sneaker waves. Washington is also preparing for heavy rainfall and rising stream flows as the atmospheric river makes its approach.In conclusion, while significant weather events shape the forecasts for various regions, it is noteworthy that other states report no substantial updates. The potential for severe thunderstorms is deemed low across the nation, and the SPC's Day 1 outlook indicates no organized risk areas. As we finalize this weather briefing, we emphasize the importance of safety and vigilance among our listeners, especially those in areas under advisories. Staying informed through local forecasts is essential to ensure preparedness in the face of these weather challenges.Takeaways: The podcast discusses the ongoing soaking fall storm affecting the Northeast, which may cause localized flooding. In the western United States, a series of Pacific atmospheric rivers is expected to arrive imminently, impacting Washington and Oregon. Warnings have been issued for dangerous surf conditions along the U.S. East Coast due to long period swells from Hurricane Melissa. Coastal regions in Southern California are advised to be cautious of hazardous surf and strong rip currents this weekend. Gale warnings and storm advisories are in effect on various coastal waters as the low-pressure system moves northward. There are currently no significant severe thunderstorm risks reported nationwide, indicating a relatively calm weather pattern elsewhere. Sources[NWS | https://www.weather.gov/phi/marine][NWS | https://www.weather.gov/sew/][NWS | https://www.weather.gov/pqr/][NHC | https://www.nhc.noaa.gov/text/refresh/MIATCPAT5+shtml/][SPC | https://forecast.weather.gov/product.php?site=JKL&issuedby=DY1&product=SWO&format=TXT&version=1][USGS | https://earthquake.usgs.gov/earthquakes/map/][NWS Los Angeles/Oxnard | https://www.weather.gov/lox/][NWS Gray/Portland | https://www.weather.gov/gyx/][NWS Boston/Norton | https://www.weather.gov/box/][NWS Mount Holly | https://www.weather.gov/phi/dss_port][NWS Mount Holly | https://www.weather.gov/phi/marine][NWS New York/Upton | https://www.weather.gov/okx/][NWS Medford | https://www.weather.gov/mfr/][NWS Portland | https://www.weather.gov/pqr/][NWS Seattle | https://www.weather.gov/sew/][NWS (national) | https://www.weather.gov/phi/marine]