RALEIGH, N.C. (WNCN) — The weather story thus far this week in North Carolina has been a stretch of cool, cloudy, and drizzly days. They certainly haven’t been as much of a washout as last Saturday was with Tropical Storm Ophelia moving through the state, but it’s a stark change from the 100° highs we saw earlier this month.
The change this week is thanks to cold air damming, also known as the Carolina Wedge. It’s a setup we see every so often in the Carolinas and Mid-Atlantic, particularly in the winter and transition months.
It starts with an area of high pressure (calm weather) parked across New England or Eastern Canada. Since high-pressure systems spin clockwise, that drives a northeast wind down toward us, bringing us cooler and much less humid air. Couple that cooler air with a stationary front just off the Carolina coast and the Appalachian Mountains to the west and there’s nowhere for the cool air to go.
Since cold air sinks, a layer of warmer air typically moves in from the west over the mountains over top of the cooler air. At that intersection of cool and warmer air is where clouds and occasionally some light rain form.
That combination gives us cloudy days like what we’ve seen this week with temperatures well below average. The pattern should change by this weekend, giving us some more sunshine!