We have somewhat similar storm systems coming through Monday, Wednesday and — possibly — about Saturday. The first two are vey likely tracking to our northwest, without sufficient blocking to hold in cold air in Southwest Virginia, so they will be mostly rain — and maybe a lot of it, adding them together. Monday’s storm system is likely to leave a quarter to a half inch on much of our region, with some spots maybe topping half an inch, as shown on the Hydrometeorological Prediction Center rainfall map through Monday evening. Because Gulf moisture will be overrunning cold air at the surface, some sleet will probably fall in the early stages of the rain on Monday morning — that may be the pecking you hear outside your window. I wouldn’t even rule out a few wet snowflakes, especially north of Roanoke — NAM model tonight actually pulls colder air in close to us for a little while on Monday. But it won’t last long. Some pockets may also be cold enough for freezing rain for a while — a few counties to the northwest, including Bath and Alleghany in Virginia, are under a winter weather advisory for this possibility. A much stronger storm system will track west of us on Wednesday, with some rain possibly reaching our area late Christmas after would should be a fairly nice Christmas Day. Rainfall estimates for our region still exceed 1 inch on Wednesday, as the track and possibly a second low forming near us will throw lots of moisture against our mountains on southeast winds. The only winter caveats on this storm: (1) again, maybe some sleet at the outset; (2) some models do want to change the backside of the rain over to snow for a bit late Wednesday — I’m very skeptical of this, on a historical basis, east of I-77; (3) upslope snow showers again on what could be strong and gusty northwest winds behind the storm, similar to Friday’s. The Saturday system is still very much of an enigma, on multiple levels, so I won’t dig into it much yet. As you can see in the weekly Snow Meter below, as copied from today’s Roanoke Times, I kinda blew it off for now — maybe to my eventual detriment.
Snow meter, 12/24-12/30
Scale of 0 to 10 snowflakes for chances of 1-inch of snow during next week (Monday-Sunday), with zero meaning no chance and 10 meaning certainty.
Roanoke (3 snowflakes out of 10) ***
Blacskburg (3 snowflakes out of 10) ***
Outlook: I thought this was going to be a hard week to pick, with a storm system moving toward us that would be a razor-thin call between rain, ice and snow on the day after Christmas. But now, there is only the tiniest chance that enough snow and sleet could fall at the outset of Wednesday’s rain to bust my 1-inch marker on the snow meter. It’s doubtful anything more than a few sleet pellets will fall, as a strong low-pressure system tracks to our west, with nothing to the north really holding in the cold air. It will sweep in milder air and thick moisture for a much-needed rain – hopefully it can start refilling Smith Mountain Lake and other depleted reservoirs. Beyond that, there will be a similar chance of snow showers to what we just had, forming with northwest winds blowing over the Appalachians, late this week behind the low and a cold front. There might be another fairly weak system next weekend, but it’s too far out and too iffy to put much stock in. I do think it’s finally going to get harder for me after this week.
Looking back: This past week worked out just about like I thought, with Friday-Saturday snow showers and flurries, but trace amounts at Roanoke and Blacksburg. Score the week a victory for below-five snowflake picks (four at Blacksburg, two at Roanoke) and not getting an inch of snow.
Current records: 3-0 for Roanoke, 3-0 for Blacksburg.