Great Question……..February 6th, 2013 at 3:31 pm by Chad Evans under Chad's WLFI Weather Blog
Val had a great question here on the blog.
Will the upcoming rain & wet ground make more moisture so we can get more snowfall with the next system that has cold air with it (with dry air eating up a lot of snowfall this winter)?
This is a good point. Usually our snow eaters have little to do with our moisture, but the moisture west or northeast of us (where our surface air is coming from). If there is a Plains drought, dry air there may eat up snowfall, but usually it is very dry, cold air originating off large expanses of land. HOWEVER, Plains drought can veer low-level jet too far to the east & southeast, drastically cutting down on our moisture, instability & even forcing. On the other hand, this dry, cold air over a large expanse of land usually comes from eastern Canada & then either directly bleeds in or get recycled into our area around high pressure to our east. If very dry, cold air penetrates deep into the southern U.S., even with a warm up & south wind, that dry, cool air will get re-pushed/recycled up into our area before robust southerly flow can truly push it out or falling precipitation can moisten up a deeply dry layer.
Southeast breezes are often pretty dry in winter, too. you tend to get downsloping air off the Appalachians, which can dry air more as it moves towards our area.
These give us our typical snow-eaters or precip eaters here.