East Coast Storm Next Week: All Wet or All White?

Jon Erdman
Published: February 19,2016 



 

Another East Coast storm appears likely next week, bringing snow, ice, rain, wind, even some severe thunderstorms to parts of the East and South. This comes on the heels of what was and will continue to be an early taste of springlike warmth through the start of the weekend.
It may be a case of déjà vu after the mess left behind by Winter Storm Olympia.
(RECAPS: Over 20 Inches of Snow | Tens of Thousands Without Power | South Tornadoes)
It's still far too soon to be confident of the details, such as how much snow, rain or ice this storm may wring out in any area. With that said, much of the East Coast can expect to be impacted by this storm system, in one way or another.
One reason for this is the jet-stream disturbance responsible for this potential East Coast storm as of Friday night was still 3,000 miles away from the West Coast, having recently ejected east from the vicinity of Japan.

It will be traveling over a relatively data-void region of the Pacific Ocean until Sunday, meaning numerical forecast models may have difficulty resolving important details of this upper-air disturbance important to an accurate forecast of the potential storm next week. It's a basic concept of forecast models that initial errors in analysis or short-term forecasts amplify with time.
However, there has been enough of a consistent signal in our longer-range guidance to suggest a storm is on the table next week. Let's break down what we know, and, frankly, don't yet know.

The Setup

After a thaw reaches the East Coast this weekend, a weak cold front should drop south into the Northeast and Ohio Valley Monday.
Then, a vigorous jet-stream disturbance is forecast to carve out a deep southward plunge of the jet stream over the East Tuesday.
If energy from the northern-branch, or polar jet stream, is able to overlap with that from the southern-branch, or subtropical jet stream, low pressure could strengthen rapidly as it moves up the East Coast the middle of next week.

Potential Setup Next Week

In addition to whether this scenario will actually come to pass, there are two key uncertainties that will determine the storm's impacts:

1. How strong will the cold air initially in place be? How easily, or soon, will it give way?
2. What will the track of the surface low be?
3. Will there be two areas of low pressure? If so, the threat may linger into late week.

The Outlook

While the precise details cannot be determined yet, there are some generalities of this potential Eastern storm beginning to take shape.
First, rain and thunderstorms are expected to flare up across much of the South by Sunday and Monday. Some of these thunderstorms could be strong or severe.
(MORE: Severe Thunderstorm Threat Returns)
By Monday night a mix of rain and snow may develop in portions of the southern and central Appalachians. Then by Tuesday, some Gulf moisture begins to meet up with the southern fringe of the cold air mass lingering over the Northeast, bringing the chance for some wintry precipitation from the Appalachians to southern New England.

Outlook Next Week

Next Tuesday through Friday, one or more areas of low pressure could intensify near the East Coast. Here's what the preponderance of the evidence suggests, right now:

• Best chance for snow, possibly heavy: Appalachians, eastern Great Lakes and interior Northeast
• Rain/snow uncertainty: Near the I-95 Northeast corridor, precipitation could start as snow and change to rain. How much snow vs. rain depends on the forecast track of the low and the cold air available, which is uncertain, although recent data suggests low pressure may track further inland, resulting in a warmer scenario along the coastal plain.
• Ice: There may also be a narrow zone of freezing rain, for a period of time, similar to what we saw with Winter Storm Olympia, though this doesn't appear to be a setup conducive for a significant ice storm.
• Wind: If the low(s) intensify, there could be blowing/drifting snow, as well as strong winds ahead of the cold front in the storm's warm sector.
• Severe Threat: Given the combination of the strong jet stream and warm, moist air, severe thunderstorms and tornadoes are possible in the Deep South and Southeast as soon as Monday, continuing into Tuesday and possibly Wednesday.

(MAPS: 10-Day Forecast Highs/Lows | Weekly Planner)
For now, don't change any plans for next week just yet. Continue to check back with us at weather.com for the latest on this potential storm and any likely forecast changes ahead.

MORE: Winter Storm Olympia (PHOTOS)