A powerful storm is set to drench parts of the eastern US with heavy rain, gusty winds and coastal flooding on Friday and Saturday, with the Gulf Coast and Southeast to be hit hard by thunderstorms just a day after being inundated by multiple of tornadoes. The local National Weather Service for Baltimore and Washington DC is calling the impending weather event, which hasn't been named, one of the biggest in up to 20 years. It has warned that Baltimore could be hit by four foot coastal tidal surges, with locals given sandbags to try and protect their properties from the anticipated floods. 'One of the biggest tidal flood events of the past 10-20 years (possibly since Hurricane Isabel at some locales), is expected Friday & Saturday. Those along tidal shores should get ready for exceptional tidal inundation!' the NWS tweeted Thursday. Isabel struck the area in 2003, which caused $945m of damage in Maryland and Washington and killed one person. The agency reports that over 20 million people are currently under a weather alert, as two-to-four feet of coastal flooding is expected to hit Baltimore and the nation's capital, with parts of northern Virginia also under flood watch through Friday afternoon, according to the NWS. Baltimore's Department of Transportation even distributed sandbags to city residents Friday morning through mid-afternoon, local news outlet WJZ-TV said. Nearby Annapolis, which sits on the Atlantic coast, has already seen water levels rise, with one man filmed kayaking through a flooded parking lot. Pictured: forecast for Friday and Saturday's powerful storm, set to drench parts of eastern US with heavy rain, winds and coastal flooding The local National Weather Service for Baltimore and Washington DC is calling the impending flooding one of the biggest in over a decade in a tweet, pictured, posted Thursday Pictured: Konrad Karandy of Annapolis, Md., puts sandbags in front of a restaurant in downtown Annapolis, Thursday, as the water from tidal flooding rises A bicyclist trudges through knee-high flooding in downtown Annapolis on Friday. The city is anticipating potential historic flooding conditions in low-lying areas this Friday and Saturday Businesses in the area could be seen placing sandbags Friday afternoon in an effort to protect their properties from flood damage. Mission BBQ in Annapolis manager Konrad Karandy was one of those businesses who took advantage of the sandbags as he prepared for flooding and extreme weather conditions. 'We're prepping for the worst. My personal guess is four feet (of water), something like that,' Karandy told the news outlet. The NSW claims that the last time weather conditions were this extreme was back in 2003, when Hurricane Isabel devastated the region, which left a total of 51 people dead, wind gusts up to 168 miles per hour, and $3.6 billion (2003 USD) in damages, the Washington Post reported in a 10-year retrospective in 2013. Meanwhile, the Potomac River, which runs through Washington DC, was already experiencing minor flooding by 1 am Friday, with conditions predicted to worsen through Saturday. Pictured: A man rides a bicycle through flood waters in downtown Annapolis, Maryland, on Friday, October 29 A group of people, pictured, wade through flood waters in downtown Annapolis, Maryland, on Friday A pair of friends appeared to be enjoying the extreme weather in Annapolis, but forecasters say conditions could soon turn dangerous Pictured: a street by the City Dock of Annapolis, Md., is flooded near high tide on Friday The Severn River in Annapolis, Maryland, is also expected to undergo similar flooding. Several counties are already under wind advisories, with gusts predicted to reach upwards of 60 mph. 'Damaging winds will blow down trees and power lines. Widespread power outages are expected. Travel will be difficult, especially for high profile vehicles,' the local NWS said. Christopher Rodriguez, director for Washington DC's Homeland Security and Emergency Management, warned businesses in the area to have their flood insurance documents handy in preparation for what could amount to expensive and devastating damages. Chase Sutton, pictured, of Annapolis, Md., kayaks over a street in downtown Annapolis Friday Pictured: a woman attempts to move her parked car from flooded Union Street as tidal flooding coincides with a powerful storm in downtown Alexandria, Virginia on Friday The Kunta Kinte-Alex Haley Memorial, pictured, located at the City Dock in historic Annapolis Md., is surrounded by water from tidal flooding, on Thursday Pictured: a group of people walk on the sea wall as a man kayaks through the flooded parking lot in downtown Annapolis, Maryland, on Friday Jay Fleming, pictured, kayaks as he surveys the flooding in Annapolis, Friday, with city is anticipating potential historic tidal flooding conditions in low-lying areas Friday and Saturday 'We want to make sure that our businesses that are along those coastal areas of our region, in particular our city, make sure you know where your insurance papers are, because flood insurance is going to be really helpful as we recover from this event over the next 48 hours,' Rodriguez told WJZ-TV. Schools in Maryland's Hartford and Calvert counties had previously announced their closing on Thursday night in anticipation of the flooding and extreme weather conditions. In the Northeast and Mid-Atlantic, heavy wind gusts reaching upwards of 30 to 40 mph are expected to hit on Friday and Saturday. And residents of New York City can expect heavy rain on Friday night, with downpours set to arrive in southern New England late Friday and into Saturday, according to the Washington Post. Parts of the Deep South are also bracing for extreme thunderstorms, just days after a swarm of localized tornadoes tore through the region on Wednesday. All rights reserved for this news site (dailymail) and under his responsibility