On Friday morning, tens of millions of Americans woke up under a winter, wind or flood-related weather alert ahead of the massive March storm that was heading east.
Through the day on Friday, a stripe of snow was expected to fill in from extreme northern Texas to upstate New York. Cities preparing for wintry precipitation included Cleveland; Memphis, Tennessee; and Buffalo, New York.
On the southern side of the storm, many locations along the Gulf Coast, Southeast and Florida were already dealing with torrential downpours on Friday morning, with the heavy rainfall expected to continue through the day.
Up to 6 inches of rainfall was possible for portions of northern Florida, where the flash flood risk was highest.
By Friday night, severe thunderstorms are expected to break out across parts of the Southeast and Gulf Coast. Damaging winds up to 75 mph will be the greatest risk followed by a few tornadoes. The storms are expected to continue all night, so there is concern for nocturnal tornadoes, which are more than twice as deadly as their daytime counterparts.
Cities to watch for the severe storm threat include New Orleans; Mobile, Alabama; Tallahassee and Jacksonville in Florida; and Savannah, Georgia.
On Saturday, the severe thunderstorms will be ongoing during the morning hours across Florida and the Carolinas before exiting off the Atlantic coast before noon.
At the same time, the storm system will be rapidly intensifying as it moves up the coast bringing rain, snow and wind from the Appalachians and Mid-Atlantic up through New England.
The I-95 corridor is expected to start with rain during the early morning hours of Saturday, then change to a rain/snow mix by mid-morning before likely ending as all snow later in the day.
The corridor can expect a slushy coating to a few inches of snow, including in the Washington, D.C., and New York metro areas.
Snow totals of 6 to 12 inches, locally up to 14 inches, will be possible across the interior Northeast as well as in the highest elevations of the Appalachian Mountains, Adirondacks and Green and White Mountains.
By Sunday, all precipitation will be off the Atlantic coast early, but strong winds and bitter cold wind chills will remain.
March snowstorms can be challenging to forecast in terms of snow totals, because a strong spring sun angle can play a role in reducing accumulations. Take into account the bulk of the snow will be falling during the daytime hours and after several days above freezing, and those factors can also impact the ability for snow to stick right away.
This storm, however, will have exceptionally cold air to work with when the arctic front arrives and precipitation rates are expected to be heavy, with snowfall rates of 2 to 3 inches per hour at times. These factors may be enough to overcome the limiting factors of sun angle and warm ground temperatures, to result in significant snowfall accumulations for some.
The largest footprint of the storm will likely be the widespread, powerful wind gusts of 40-50 mph from the Southeast to New England which will lead to blowing snow and sporadic power outages.
Another headline this weekend will be the plummeting temperatures in the wake of the storm and a possible flash freeze event across the Northeast.
As the arctic front blasts through the region mid-day Saturday, temperatures could crash more than 10 degrees in 3 hours, eventually dropping below freezing . This will cause any precipitation on the road to freeze instantly, creating icy conditions and treacherous travel.
Bitter cold wind chills will be possible Sunday morning across New England, before temperatures rebound Sunday afternoon into early next week.