Another dense fog advisory has been issued overnight/early Sunday for a similar portion of the region as last night. Fog probably won’t be as widespread as late Friday and early Saturday, but could be dense and hamper travel in some locations.
There is so much going on with the weather pattern, short term and long term, that it’ s hard to boil all of it down. Perhaps this is a format I can replicate in the future. Here are the “Big 5″ weather points, based on impact and likelihood, for Southwest Virginia looking forward from Sunday.
(1) Record highs likely again on Sunday. Roanoke’s 73 and Blacksburg’s 71 on Saturday set new standards for Jan. 12, eclipsing previous marks from 2005. Roanoke’s high made for the hottest January day in 8 years, while Blacksburg’s appears to be the second-warmest January day in its entire period of record, dating to 1952, beaten only by a 73-degree day on Jan. 30, 1975. The same southwesterly winds at the surface and aloft, plus in-and-0ut sunshine, will continue the springlike weather for another day, with many temperatures topping 70. Roanoke’s record high for Jan. 13 is 73, set in 1932; Blacksburg’s record is 64, set in 2005. It appears Blacksburg’s record is very likely to fall and Roanoke’s has a good chance. Sunday will be the end of the record warmth, and quite likely the last truly springlike day we’ll see for weeks — maybe even until spring itself.
(2) Good chance of soaking rain Monday-Wednesday. As the leading edge of much colder air that has invaded the western half of the U.S. grinds against high pressure off the Southeast coast that has helped bring us record warmth, the cold front will stall, and only sluggishly advance eastward through the early to middle part of the coming. Waves of low pressure moving along the slowing front will bring abundant moisture from the Gulf of Mexico, leading to periods of rain, especially on Monday and Tuesday, maybe leaking into Wednesday too. The Hydrometeorological Prediction Center is expecting 2-plus-inch amounts to be common this week, mostly falling during the 72 hours ending Tuesday evening (which really means the 48 hours beforehand, since no rain is expected through Sunday evening). Rainfall will be enhanced some by southeasterly winds blowing up the slope of the Blue Ridge as low-pressure centers move up the front. Roanoke has not topped 2 inches in a single rainfall event since Sept. 17-18. Much of the region continues in moderate drought, so though it will be messy outside, the rainfall is needed.
(3) Much colder period ahead for late January. This will become a huge weather story, not just locally, but nationally, if what many long-range forecast models show comes to reality. Extremely cold air, displaced southward by a “sudden stratospheric warming” event over the North Pole that began about3 weeks ago, is expected to move southward through central and eastern North American over the next 1-2 weeks. While the first chunk of this cold, in a greatly modified fashion, will bring our temperatures back down from intensely warm this weekend to near-normal January cold by late week, it is the subsequent pushes of cold air afterward that will have the potential to bring unusually cold weather to much of the central and eastern U.S., including Southwest Virginia, generally in the Jan. 20-30 timeframe. It’s hard to tell exactly how cold it will get, but it would be a good time to review what to do about your water pipes and make sure heating systems are in top-notch working order just in case the most extreme cold scenarios comes to fruition.
(4) Some ice/snow risk as cold penetrates back side of precipitation shield Tuesday. The cold air will only be grudgingly moving eastward, but enough of it may move in by Tuesday that some ice or snow may be possible, primarily in the highest elevations (3,000+ feet) and along/north of the I-64 corridor. The Hydrometoerological Prediction Center has highlighted a few higher spots around the region on its map for a slight risk of heavy ice (.25 inch or more ) mostly on Tuesday. The HPC also has posted maps showing a low-end risk of 1 or more inches of snow generally along and north of the I-64 corridor for the 24 hours ending at 7 p.m. Tuesday, and also a slight risk for light icing farther south in the same time frame. This is an iffy situation and will most likely be spotty, if it develops at all.
(5) Late-week snow chance not entirely out of the question just yet. The forecast models have been bouncing around on some upper-level energy moving across the South on or near next Friday. This just remains something to keep one eye on, as there is at least some potential for snow (or mixed precipitation, or cold rain) if a sizable low were to throw moisture over marginally cold air late in the week.