Friday, 11:30 a.m.
As one very cold air mass begins to fade going into the weekend, another will quickly move in to replace it. This arctic outbreak will originate farther west, and it will have more far reaching impacts across the South, though it will also cause almost all of the same areas that have been cold the past few days to shiver. The weekend storm tracking across the country will help pull this next arctic air mass in from western Canada as it reorganizes over the southern Plains tomorrow then heads eastward this weekend.
The cold air is already impacting the Northwest with very low snow levels and snow showers scattered across parts of Washington and Idaho into Montana and Wyoming. With the emergence of low pressure in the lee of the Rockies late tonight and tomorrow morning, the colder air will drill down the Front Range of the Rockies, causing snow to break out overnight. This is the 500mb forecast for tomorrow evening, showing the upper-level low rolling into Kansas:
As the day progresses, that snow will fan out across Kansas and southern Nebraska, then into parts of Iowa and northern Missouri. Now there is a lot of warmth in Texas right now, and some of that warm air will try to surge out of the southern Plains into the Tennessee Valley. That will spark rain and thunderstorms, and some of those thunderstorms are apt to be severe tomorrow afternoon and tomorrow night into Sunday as they move through the South and into the Southeast. The core of the severe weather may be across the interior South, along with the heaviest rains, but with dew points in the 60s along the Gulf Coast ahead of a cold front, there can be locally severe thunderstorms there, too.
This is going to split into two 'events,' if you will. The first will be the warm advection event I've just described. The northern end of it will be in the form of snow across West Virginia into northern Virginia and Maryland, but much of this will slide off the mid-Atlantic coast later tomorrow night. The second half of it will be with the upper-level low itself. Most of the precipitation with that will be in the colder air, meaning snow, and that will roll into the Ohio Valley Sunday, then spread into the northern mid-Atlantic later tomorrow night and linger into Sunday before ending. There will also be some wet snow in southern New England, too. I advise you to check in with AccuWeather.com throughout the weekend for storm updates and updated snowfall forecasts for your area.
Then we can head into spring, right? Wrong. As stated, the cold is reinforced behind this storm over a much wider area. Look at the projected temperature anomalies for Tuesday:
The problem is that there is still way too much cold air on the playing field, and there's too much blocking that is forcing the jet stream much farther south than you'd normally see this late in March. And that leads me to the belief there is at least one more snow chance as we head into the Easter weekend. It looks as though there will be a large surface high over the northern Plains next weekend, and there's still going to be a west-northwest flow aloft from the Rockies to the East Coast:
All of the cold air still lying around going into next weekend leads me to believe snow is possible with any disturbance coming out of the Rockies and heading eastward across the Plains toward the East Coast. Perhaps it is simply farther north than will be seen in the next 72 hours. That would only make sense given the lateness of the month. Maybe that will be winter's last gasp. Maybe. I am of the opinion that by the middle of the month, the pattern will be changing for the warmer in most of the country, which will ultimately be a big jump from being 10 to 20 below normal to something above it. If you factor in an average temperature jump of 6 to 8 degrees over the next three weeks, and we go from, say, 15 below current levels to maybe a handful above by mid-April, that is effectively a 25- to 30-degree temperature swing. That means going from highs in the 30s to highs in the 60s in some cases. Again, that's a rough guesstimate of the change forthcoming. Some days that change may be even greater!
Two systems will delay the onset of warm weather in the Ohio Valley and the East over the next week or so, but then it should get warm all across the country heading into the Memorial Day weekend.
A turn to much colder air over the Northeast and mid-Atlantic states will set the stage for a rain and snow storm later this weekend before it turns much warmer later next week.
It's warm now, but will turn much colder this weekend, with a storm threat later Saturday into Sunday. Warmth will return by the second half of next week.
Though it is cold now east of the Mississippi, with a couple of opportunities for snow into the weekend, a blast of warmth is due for much of the country east of the Rockies next week.
Warm air will once again surge eastward from the Plains to the East Coast this weekend and early next week. A strong storm next Tuesday and Wednesday will then be followed by colder air later next week.
A storm in Southeast Texas will generate severe thunderstorms this afternoon and tonight, and some wet snow on its western flank as it heads into the Ohio Valley tomorrow.