Tuesday, March 19, 2013

Spring? Not for 2 weeks, computers say

It's getting more obvious by the day that the atmospheric blocking pattern I wrote about Monday will have a profound effect on weather in the Charlotte region, the Carolinas, and the eastern United States for the next few weeks.

If you take the computer models at face value, it appears as if we won't see any prolonged spring weather until at least the period around April 7-10.

That includes prospects of a chilly Easter weekend, late-season frost and freeze, and even a chance of snow this weekend in the northern part of North Carolina (especially the mountains).

First, a review.  The Atlantic Oscillation (AO) has gone strongly negative, and with high pressure in place near Greenland, we have a classic "blocking pattern" across the eastern United States. That means the jet stream has a big kink, allowing very cold air from Canada and points north to race southward, into the eastern United States.

At the same time, any storm system that glides from the Pacific into the continental United States will encounter this cold air, and we face the possibility of wintry weather -- even though the calendar says "spring."

Such an event is taking place today in New England, with heavy snow forecast for places like Hartford and Boston, and up into Quebec.  Air travel to places like Hartford, Boston, Montreal and Portland (Maine) could be impacted.

As a series of cold fronts moves across the Carolinas over the next few days, there could be a bit of mountain snow.

Certainly, ski slope operators and ski enthusiasts will love all this. The ski season, which ended very early in 2011 and 2012, apparently will continue into April this year in the North Carolina mountains.

By this weekend, the computer models continue to advertise the development of two storm systems. It's the second system, expected to move through the area later Sunday and Monday, that bears watching. Cold air will be locked firmly in place across the Carolinas, in a "wedge" pattern as was the case Monday.

In Charlotte, for example, I could see Sunday's temperatures stuck in the upper 30s and low 40s again.

The models can't seem to agree -- as usual -- on the path of the Sunday storm.  The trend seems to be pointing toward a snowfall for the Ohio Valley and Middle Atlantic. But there could be wintry precipitation north of Interstate 40 at lower altitudes.

And there doesn't seem to be any sign of a temperature recovery to average levels (middle and upper 60s) next week -- at least, not for anything more than one day at a time.  The trend seems to be for below-average temperatures through Easter, and for that matter, through the first week of April.

We'll continue to watch this pattern in coming days.


Anonymous said...

What the hell happened to "winter is dead stick a fork in it"?!?! One week it's "But there is no sign of real cold weather that would allow a passing storm system to drop snow in our region", the following week it's this storm bears watching.

One week, average temps, the following week, cold for the next 2 weeks. I also remember back in February when is was said normal March temps would return after St Patrick's Day. Now we're back to below even January temperatures.

I'm encouraging all of my children to become weathermen, as you can just make stuff up and then a week later do a complete 180 and predict something the complete 100% opposite of your last forecast.

I don't understand why meteorologists try to predict long range forecasts. One day it's one thing, the next it's another. Don't waste our time.

Jumped the gun a little on that winter is dead article didn't ya?

Winter Lives!!! said...

When he "stuck the fork in it," it jumped up, still alive. It is quite comical how these dramatic and authoritative predictions so frequently result in the opposite. Those "reliable" crystal balls they use seem to be defective.

Anonymous said...

I am definitely in the wrong field. How many times are weather guys completely wrong and they still keep their jobs. Most of us in other fields would be fired on the spot.

Lying...it's the only way people will read your columns these days.