Will it finally warm up in April?

Now that we've suffered through several weeks of unseasonably cold weather and are headed for one of the coldest months of March in Charlotte weather history, can we hope for something better in April?

The answer is "yes" -- sort of.

Climatology -- the increasing angle of the sun, the inevitable march toward summer -- will help insure that the pattern which has brought a winter-like chill to the Carolinas and the rest of the eastern United States this month will relent in April.

But don't expect the cold-weather switch to be turned off abruptly.

We'll begin to see better weather, as early as this weekend, but the progress into spring won't be smooth. And frequently in April, I think we'll be on the edge between warm weather and the chilly stuff.

First, a review.

The Greenland block -- high pressure at upper latitudes -- that some weather followers had been expecting all winter finally arrived in March.  Strong high pressure in the area near Greenland blocked the typical west-to-east jet stream pattern. Instead, it created a bend in the jet stream, which nose-dived from western Canada into the eastern United States.

That brought a persistent flow of cold air into our region.

The lower end of that buckled jet stream will retreat northward, beginning this weekend. But it won't disappear.

Most meteorologists expect the blocking pattern to remain intact for much of April. The only difference is it won't be as persistent in the southern United States.  Draw a line from Richmond, to southern West Virginia, across southern Kentucky, and into Missouri. Area north of that line can expect to remain in the colder air for the next few weeks, still under the influence of the blocking pattern.

Down here in the Carolinas, we'll see periods of warm weather.

But every now and then -- maybe once a week, for a day or two -- the jet stream will dive southward into the Carolinas briefly.  That will bring a short period of much cooler weather, before the jet stream pushes back to the north.

It means we'll have several days in the 60s and 70s, but a back-door cold front will push into the region from the north, and we'll have two days of cold-air damming -- with temperatures in the 50s and a chilly breeze.

The best guess among meteorologists is that the pattern will come to an end in later April.

Basically, this means our weather is about three to four weeks behind schedule.  These inconsistent stretches -- a few mild days, then a day or two of chill -- are more common in March.

This also means severe weather is less likely in April than later this spring. We'll talk more about this later in the week, but springtime severe thunderstorms and tornadoes are more likely to the south and west of the buckled jet stream -- in places like Arkansas, Louisiana, western Tennessee, Mississippi, Alabama and southern Georgia.