RICHMOND, Va. (WTVR) – As I explained in my previous blog posting, it looks like our weather pattern will keep Virginia cooler-than-average for the end of March. The Vernal Equinox may be tomorrow (March 20, 2013), but we may still be talking about Winter weather during our first days of Spring.
Here is the latest temperature outlook for the U.S. through the end of the month, which highlights the Mid-Atlantic and Carolinas as very likely being cool to chilly.
So what is the cause of this? Specifically, it looks like an area of high pressure will settle over Canada’s Hudson Bay region, while a low pressure region spins northeast of New England. The jet stream will continue to ride over the Rockies, then dive southeast over our region from the Plains, keeping us on the cool side. This jet stream also transports storm systems and disturbances our way like vehicles riding on a highway.
Blocking patterns like the Arctic Oscillation and the North Atlantic Oscillation will likely remain negative through the end of March, which is often associated with cooler weather in Virginia. The National Snow and Ice Data Center monitors these patterns because they impact Arctic sea ice. NSIDC says, “When the Arctic Oscillation is in a negative mode or phase, sea level pressure is higher than normal over the central Arctic and lower than normal over middle latitudes.” The forecast takes both of these indices potentially even deeper than they have been all Winter, which would be significant.
Climate Prediction Center
Climate Prediction Center
That said…both the European and GFS weather models are consistently (meaning from computer run-to-run) indicating a storm system riding along the jet stream, developing a coastal low in our region, and bringing precipitation that will fall into cold air. That would mean rain and snow, with the precipitation type, timing and placement depending on the track of the low and the depth of the cold air (or sub-freezing layers) above ground. The time-frame we are closely monitoring is Sunday through Tuesday of next week, March 24 through 26.
It’s not unheard of to get an early Spring snowstorm in Richmond. Here are some Spring snowfall stats to whet your appetite:
A lot has to come together just right for a late-March snowstorm, but it does look like at least a couple of factors are shaping up for us, from cooler-than-average weather to our potentially strongest negative AO phase of all this snow season.
Meteorologist Carrie Rose
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