At a Glance

Winter Storm Grayson will bring freezing rain, sleet and snow to the Southeast coast on Wednesday.Snow and gusty winds will then affect the Northeast coastline Thursday and Thursday night.The track of surface low pressure off the Eastern Seaboard will dictate who sees snow and how much will fall.Near-blizzard conditions could occur in coastal New England and on eastern Long Island.Minor coastal flooding is possible along New England Coast on Thursday. Power outages are likely in parts of the East.

Winter Storm Grayson will spread aswath of snow and ice from north Florida tonight to New England into Thursday as a large, powerful low-pressure system rapidly intensifies off the East Coast.

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Winter storm watches and warnings have been issued from the Florida Gulf Coast to Maine's Canadian border due to expected snow and ice impacts from Winter Storm Grayson.

Let's start with warnings in the Southeast and then the mid-Atlantic and Northeast. Following warnings, you'll find details on timing and how much snow and/or ice you'll get below.

Winter storm warnings have been issued forportions of northern Florida, including,southeastern Georgia and in the easternCarolinas, including and .

Yes, you read that right. Winter storm watches and warnings have been issued as far south as parts of north Florida, coastal Georgia, and the Lowcountry of South Carolina, including the cities of , and .

This is the first winter storm warningissued by the National Weather Service office in Tallahassee, Florida, in almost four years, since Winter Storm Leon produced snow and ice over much of the Southeast, leading to travel chaos in cities such as ,Birmingham, Alabama and Tallahassee, Florida.

Winter weather advisories are also in effect for another narrow strip of south Georgia and north Florida just west of the city of , and for north-central and northeastern Florida, including .

Winter Weather Alerts

(From the National Weather Service.)

With plenty of cold air in place over the East and South, a threat of freezing rain, sleet or snow is expected along the Southeast coast.

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After the Southeast ice and snow is over, low pressure intensifying off the New England coast will spread snow and wind into parts of the Northeast Wednesday night-Thursday.Near-blizzard conditions are possible in coastal New England.

Winter storm watches have been issued along the U.S. East Coast from portions of the Virginia tidewater northward through eastern Long Island into eastern New England.

Watches are posted mainly east of the larger metropolitan cities, with the exception of Boston, which is under a winter storm watch for significant snowfall.

Blizzard conditions are possible in the entire state of Maine, andheavy snow is also likely. Blizzard conditions are also possible in southern New Hampshire and on eastern Long Island.

Winter Weather Alerts

Let's break out the forecast by region starting with the Southeast.

Southeast Ice, Snow Threat

Some conversational flurries arepossible during the overnight hours in parts of southern Mississippi and southern Louisiana. No accumulation is expected.

The first higher end impacts are expected as precipitationbeginswrapping into the subfreezing air overnight in parts of interior north Florida and south Georgia, likely as freezing rain.

Freezing rain or mixed precipitation is expected to begin in parts of northern Florida and southern Georgia during the pre-dawn hours on Wednesday. A few spots in the Suwannee River Valley or southeastern Georgia may see significant icing, but generally less than 0.25 inches in accretion.

Wednesday, freezing rain or sleet will continue through the early afternoon in parts of north Florida generally from Tallahassee and Apalachicola to communities west of downtown Jacksonville, to coastal Georgia. Precipitation will taper off, generally as snow, from west to east during lunchtime into the early afternoon.

A mix of snow, sleet and freezing rain will spread into the Lowcountry of South Carolina and eastern North Carolina during the late morning hours into the afternoon, and reach intothe Virginia Tidewater during the evening hours.

Wednesday's Forecast

This wintry mess may changeover to mainly snow or sleet Wednesday night from the Tidewater of Virginia to eastern North Carolina, before ending as snow early Thursday morning.

Ice Potential

A strip from north Florida and the Florida Big Bend to southeastern North Carolina could see ice accumulations of one-tenth to one-quarter inch through Wednesday. Isolated spots may see significant icing.

These accumulations typically mean vehicle windshields are coated, there's light icing in trees, and untreated bridges and overpasses may become hazardous by Wednesday morning in these areas. Power outages are likely in parts of northern Florida and southeastern Georgia, and scattered outages are possible in the eastern Florida panhandle, southwestern Georgia and into the Carolinas.

Areas from the Outer Banks of North Carolina northward to extreme southeastern Virginia may see some lighticing.

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Forecast Ice Accumulation in the Southeast

Areas in dark pink are expected to see less than a quarter-inch (0.25 inch) of ice accretion. Areas in light pink may see accumulations higher than that, capable of more widespread tree damage and power outages.

Snow Potential

Total snow accumulations of less than 3 inches are expected from parts of eastern Georgia into southeast Virginia. Some locally higher amounts are possible in the Virginia Tidewater and eastern North Carolina.

Any light snow accumulations may mask icy stretches on area roads, especially bridges and overpasses.

Travel is likely to be dangerous in these areas Wednesday into early Thursday.

Snow Forecast

(Note: This snow accumulation is in addition to any accumulations of ice or sleet.)

Northeast Storm Ahead

A farther west track would increase the potential for heavier snowfall and strong winds while a farther east track would decrease both of those threats. The yellow shaded area represents the extent of possible low-pressure center locations on Thursday via four major weather models.

The Eastern Seaboard willsee at least some snow and wind from this storm,and locations along the immediate coast of New England could see blizzard conditions, including lowered visibility and gusty, if not damaging, winds.

Low pressure in the western Atlantic Ocean will intensify and track toward the north-northeast off the Northeast coast late Wednesday through Thursday, before plowing into Atlantic Canada by early Friday.

A track of the offshore low closer to the East Coast wouldincrease theodds of moderate to heavy snow along with strong winds. A track farther offshore would bring lighter amounts of snow to the East Coast and gusty winds. The trend in recent computer model guidance has been closer to shore.

This degree of uncertainty is quite common with many East Coast snow events.

The air force hurricane hunters will fly into Grayson on Wednesday afternoon as it develops several hundred miles off the coast of Florida to better understand its strength, location and vertical structure.

Regardless of the track, the low will likely undergo what meteorologists call ,which is a rapid drop in atmospheric pressure of 24 millibars or more in a period of 24 hours. When a pressure drop like this occurs, it signals the development of a potent storm system.

Here's an overview of the timing of this storm followed by what we know about the potential snowfall accumulations right now.

Timing

Wednesday night

Potent Winter Storm Grayson will be located off the coast of North Carolina and Virginia, but its large size will bring snowfall well inland of the I-95 corridor in Georgia, the Carolinas and northward to New Jersey. Snow will spread northward through the mid-Atlantic after midnight, and into southern New England during the pre-dawn hours. Snow will reach as far north as southern Maine and western Nova Scotia by sunrise Thursday morning. Warmer temperatures near the coast of North Carolina and perhaps the southern Delmarva peninsula will initially keep precipitation as rainfall, ice or mixed precipitation, but cold air on the back side of Grayson will turn all precipitation to snow. The Massachusetts islands, including Nantucket, and Cape Cod will also start as rain, and rain will persist into much of the afternoon on Cape Cod. Wind gustsup to 50 mph are possible from coastal North Carolina northward to the southern coast of Long Island with increasing winds in New England toward sunrise.

Wednesday Night's Forecast

Thursday-Thursday night

The powerful storm will be centered well off the Northeast coast. Given its large circulation and strong intensity, the low will likely produce at least some snowfall, possibly heavy, in parts of the Northeast region. Snowfallmay spread from the Virginia Tidewater to the New York City metro and much of New England during the day. Increasing winds are likely along much of the Northeast coast. Wind gustsstronger than 50 mph are possible along the immediate coasts of North Carolina (Thu AM), New England (Thu PM) and Atlantic Canada (late Thu PM into early Fri AM) depending on the exact track of the low-pressure system. Wind gusts 60-70mph are possible on Cape Cod and for the Massachusetts islands. Power outages are likely. The winds could cause some power outages along the immediate coast of New England, which would be followed by very cold temperatures Friday-Saturday. Near-blizzard conditions could occurin coastal New England and eastern Long Island. A storm surge of several feet is likely along north-facing coastlines in eastern Massachusetts on Thursday. Gusts to 75 mph are possible more than 20 miles offshore coastalMassachusetts, and seas could climb above 26 feet. Boating is strongly discouraged. Overnight Thursday, most of the potential snowfall from this storm will be confined to parts of New England.

Thursday's Forecast

Snow Potential

The best chance for significant accumulating snow along the U.S. coast is in eastern New England. This snow may be heavy and accompanied by strong winds. Some spots along Massachusetts' Interstate 95 corridor and inDowneastMaine could see more than a foot of snow. For now, lighter accumulations are expected from the New York City Tri-state area to the Delmarva Peninsula, with mainly less than 4 inches expected. Again, exactamounts will depend on the track of the low in relation to the East Coast. Heavy snow, possibly changing to rain in some locations, is likely in parts of Atlantic Canada (Nova Scotia, New Brunswick, Newfoundland) Thursday into Friday.

Forecast changes are likely over the next few daysas the details of this potential East Coast storm come into focus.

Snowfall Forecast Through Thursday

Check back with us at weather.com for updates to this forecast in the days ahead.