Winter Solstice Monday

The Winter Solstice is Monday, December 21 at 12:47 p.m. EST. This date is regarded as the "start" of Winter for the Northern Hemisphere, and is also the shortest day of the year (i.e., with the fewest hours of sunlight). The Earth's axis is always tilted at 23.44 degrees with respect to the orbital plane, which means that different latitudes will most-directly receive the Sun's incident rays at different times of the year on the Earth's orbit.

From an observer's perspective on Earth, it appears that we seem to "shift" either toward or away from the most direct rays during the year. In actuality, we aren't tilting back and forth from the Sun's perspective, but from ours on Earth, that's what it looks like.

(Image: Windows to the Universe, UCAR)

By the Winter Solstice, the Sun's incident rays are so low on our southern horizon that much of their intensity is diffused as it travels through a longer layer of atmosphere to reach the ground in the Northern Hemisphere. The good news: our days will begin lengthening again. The "bad" news: the temperature lag on Earth means that we are just entering our climatologically coldest months. Hence, why we call this the "start" of Winter!

Getting Ready For Winter Weather

Winter Storm Watches are already going up to our southwest and into the western half of North Carolina for a strong storm system that will approach along the East Coast Friday through the weekend.
It does appear that much of Central Virginia will also receive snowfall this weekend, with the highest totals likely along and west of a line from Lynchburg to Charlottesville to north of Fredericksburg.

The storm system has been organizing south of Texas in the Gulf of Mexico over the past 12 hours:

We will be providing updates on the snowfall potential in Central Virginia as the storm approaches.

How Much Snow? Not This Much...

Above is the latest snowfall accumulation map for the upcoming weekend, indicating a range of 21-25+ inches of snow across a broad area, include the metro. Here's where you have to be very careful when using models for forecasting. While I think we will see some snow this weekend, the amounts depicted above are off the charts, and don't consider some of the most important parameters. For instance, ground temperatures are still warm and near-surface temperatures look like they will be a little above freezing for part of the event. There's also a signal that some of the precipitation will fall as rain. My feeling is that we will see snow in the metro, but how much of it accumulates is still very much in question. I do feel that some part of central Virginia could get as much as a foot of snow. I'll address the system again and have more specifics on snowfall totals on Thursday. Till then snow lovers, pray for snow!