Turning Colder, Maybe Snowier by Matt Ferguson - WSET.com - ABC13

Turning Colder, Maybe Snowier by Matt Ferguson

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We all know late fall and early winter has NOT brought real Virginia cold. Temperatures for the most part have remained way warmer than what you'd normally expect for the time of year. Yes, we have had brief spells of colder weather, but no true lasting cold. So what about the rest of the winter and the outlook for snowstorms?

By no means am I an expert in long range forecasting, but in this blog I'll highlight some weather patterns that are likely to bring colder changes.

Right now, I'm forecasting more intense cold weather from now into February, the coldest so far this winter. With that said, I still don't see it turning extremely cold and lasting the rest of the season. Look for very cold punches of arctic air, with continued frequent mild warm-ups. In any case, with the coldest weather this winter still on the way, chances of snow and ice go up!

The first weather pattern we'll discuss is La Nina (colder than average water in the Pacific). The current La Nina is in the process of going away or heading toward a neutral phase, which will help the global weather patterns across the US become more normal.

Next we look at two indices that meteorologists use in long range forecasting. The Arctic Oscillation, the first index, is becoming negative. This indicates frigid weather that has been wrapped up in northern Alaska and at the North Pole will begin to head southward. However, questions arise as to where the coldest air will end up going. Does it move into the US or does it head south on the other side of the world, such as in Russia? Well that's just a wait and see game, but at least we know more cold will be heading south and that's one of the first steps to get snowier weather.

The North Atlantic Oscillation, the second index, is tending to go from a long term positive state to a more neutral or negative state. This is good news for you snow lovers as this pattern tends to lead to a trough (or large dip) in the jet stream across the eastern US. This helps cold air pour in from Canada and more intense storms develop due to tight temperature gradients between the cold on land and milder air just off the Gulf and Atlantic Coasts. In this pattern, a storm track usually develops across the southern states then turns northeast. Stormy weather usually gathers Gulf of Mexico moisture then rides up the East Coast tapping into Atlantic moisture as well. That's the best pattern for Virginia snowstorms, however I'd like to see the North Atlantic Oscillation or NAO go way negative before I get too excited about major East Coast snow. That's something I'll be watching.

We have lately observed stratospheric warming, which is rising temperatures located extremely high in the sky above the North Pole. Again, I'm not an expert on this, but textbook meteorology tells us when this happens, we can look for colder weather to push south from the North Pole.

Officially at the Lynchburg Regional Airport there has only been a trace of snow/ice so far. However, with those pattern changes occurring, those of you who enjoy the white stuff may get it by late February. Stay tuned!!

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