The PNA is forecast to go negative
The Pacific/North American pattern is forecast to go quite negative over the next month. Take a look at the CFS forecast below.
A negative PNA implies ridging over the east and troughing over the west, which would extend the warmth we’ve seen along the East Coast this winter. Predictably, this corresponds with a CFS temperature forecast that shows precisely that, as well as some incredible warmth over eastern Europe and western Asia.
If this warmth keeps up during the next few weeks, it’s possible that grapes will begin growing for the season in the East. About half of the nights at the end of February have temperatures at or below freezing in DC, and the possibility of a March frost is quite high. This could have a negative impact on wine yields if the vineyards can’t keep their temperatures high enough.
Originally published at Weather and Vines.