Meteorological Spring is officially underway but mother nature is not going to automatically shift into spring weather mode.
The last three weeks of February was dominated by abnormally warm weather thanks in part to ridging across the eastern half of the country. That has really changed over the past week as blocking across Greenland and Hudson Bay has re-shuffled the flow across all of North America. This is commonly what we refer to a negative phase of the North Atlantic Oscillation. We hinted as this happening about a week ago and it has verified to this point.
With a negative NAO in place it forces the jet stream to ride under the block, which for us here in North Carolina means the potential for a cool and active weather pattern. The past 24-48 hours has been a perfect example of what a blocking setup can do, the powerful storm that formed off the East Coast turned into a wind machine covering a large amount of real estate.
Models are currently latched on to a persistent -NAO through the middle of this upcoming month. This will help filter colder air and a dynamic jet stream into the Southeast US.
(500 mb maps)
We look for a downturn in the temperatures this week as the region will fall several degrees below early March norms. Also with this cold air is the risk for a frost and freeze. Especially vulnerable are those plants that bloomed out last month during that string of abnormally warm weather. Here’s a look at ensemble data for both Hickory and Shelby for the next two weeks…
So…just how long does this weather pattern stay in place?
There’s some uncertainty with any long range forecast for obvious reasons but our guidance has been steady in holding a -NAO possibly to the end of the month. We shall see exactly how long it persists. One thing is for sure, March came in this year like a Lion, so to speak and it could continue to make its presence over the next several days. We are definitely in a transition of seasons…