Temperatures have been pretty even-keeled in the first week of January — seasonable cold bouncing between the 20s and 40s, mostly, with more clouds than sun most days, and not much precipitation. We’ll continue that general pattern of temperature through Monday night — but then, a wild roller-coaster ride begins, not just for Southwest Virginia but much of the U.S., that may continue much of the rest of January. I think there’s a good chance Roanoke will have a high above 70 and a low below 10 before this month is over.
The coming spurt of intense warmth is the most certain element of this roller coaster — we can see the hill we’re climbing, but don’t have a clear picture yet of where the track leads beyond the summit, except knowing it will generally be downward. Prevailing southwesterly wind flow, surface and aloft, will sweep in milder air starting Tuesday, when highs may poke above 50 in much of Southwest Virginia, more so on Wednesday, when a few low 60s are possible. The southwesterly wind flow will also bring in enough Gulf of Mexico moisture for a chance of rain Thursday and Friday — this may coincide with a temporary wedge of colder air from the northeast that will pull highs back into the 40s for a day or maybe two. But once the rain system goes by, even warmer air arrives for next weekend. We’re likely talking widespread 60s and some 70s during the Saturday-Monday stretch. Record highs for Roanoke on Jan. 12-14 are 71 (2005) for Jan. 12 (that may be reachable Saturday), 73 (1932) for Jan. 13 (that may be reachable Sunday) and 81 (1932) for Jan. 14, the hottest January temperature on record (it’s not going to get THAT warm this time!). The warm air will be curtailed rather rapidly sometime in the middle to latter part of next week. This will not be the Arctic motherlode, but the leading edge of a colder pattern easing in from the west that may hold in for several days.
How cold it gets during the colder pattern is somewhat fuzzy, but there are signals of significant blocking highs in the northern latitudes on forecast models and movement of a weakening polar vortex — the core of coldest air — into Canada and toward the U.S. that would suggest a long, very cold outbreak will be possible after Jan. 15. Also totally up in the air are the prospects of winter storms — will mid-late January be a cold, dry period, or have frequent winter storms, or something in between? It all depends on exactly where major features set up. Whatever the case, be sure and enjoy the warmth outside next weekend if you can, whether you are a sun seeker or snow lover. It won’t last long, and may not return again for several weeks or even a couple of months.
Chance of 1 inch of snow on scale of 0 to 10
Roanoke — ZERO snowflakes
Blacksburg — ZERO snowflakes
Outlook: This week will bring a warm-up as southwesterly winds dominate, bringing in much milder temperatures after two seasonably cold weeks that yielded only a little snow and ice. Highs may reach the 60s a couple of days this week, and any precipitation that falls will be rain. I can’t find a reason to give either site even a single flake on the snow meter this week. Colder weather will return, possibly in force, but that will not happen until at least Jan. 15.
Looking back: My last-minute downgrade of the snow meter with new data last weekend put this week in the victory column, as no significant snow fell at Roanoke or Blacksburg, and my snowflake numbers were below five for each. Current records: 5-0 for Roanoke, 4-1 for Blacksburg.