UPDATE 3:25 PM: The squall line resurgence is occurring along the Interstate 77 corridor, and this will spread rapidly northeastward toward the Roanoke and New River valleys and along the Blue Ridge in the next couple of hours, with strong winds and heavy rain possible as it passes. The Storm Prediction Center has indicated that a severe weather watch may be needed, once again. Follow the latest watches and warnings from the National Weather Service-Blacksburg. END UPDATE
UPDATE 1:20 PM: The severe thunderstorm watch issued earlier today for some counties west of Roanoke has been cancelled. The squall line is very poorly organized and continues to weaken as it has run out too far ahead of the cold front, the source of lift. Later this afternoon and evening we may some reorganizing of the line east of the Blue Ridge, in slightly better instability and as the cold front gets closer. For the Roanoke Valley/Blue Ridge and points west, it’s likely to be an afternoon of showers with some gusty winds, picking up into heavier rain by late afternoon or evening. Meanwhile, it’s already a deadly day to our south, with a confirmed tornado fatality in Georgia, ending a record 220-day streak nationally without a tornado fatality. Here is a video of the tornado at Adairsville, Ga.END UPDATE
UPDATE 8:50 AM; A severe thunderstorm watch has been issued through 4 p.m. for Craig, Pulaski and Carroll counties westward. It does appear the squall line is moving ahead of the schedule shown on last night’s NAM model output below — it’s already entering the far southwest corner of Virginia, and will likely cross I-77 by early to mid afternoon, entering the New River and Roanoke valleys shortly thereafter, with some heavy rain and gusty winds continuing into the evening. Stay abreast of the current location on our radar view available on the right margin. END UPDATE
It looks like we’re headed more for a late afternoon-evening period for the heaviest of the weather on Wednesday, which in Southwest Virginia, will likely consist of a squall line of heavy rain showers, possibly accompanied by strong winds and maybe a little thunder. Though we are in a slight risk zone for severe weather, the cloud tops may be relatively low, which often precludes lightning and thunder. Strong winds are the greatest risk, as downdrafts in the squall line may bring some of the very strong winds aloft to the surface. The frame at left is the approximation of what radar should look like about 10 p.m. Wednesday, with the heaviest rain blowing through western Virginia. Long before this line arrives just ahead of the cold front Wednesday night, gusty winds will pick up from the south to south-southwest, prompting a high wind warning along and west of the Interstate 77 corridor and a wind advisory elsewhere. Historically, the localities in the high wind warning have seen 60 mph gusts in similar setups as southerly to southeasterly winds crash against the ridges and roll over like waves into lower elevations. It’ll be another warm day as we await the line moving at us from the west, with 60s to low 70s possible, and perhaps some intermittent showers as moisture is squeezed out against the higher terrain. Rainfall amounts of 1-2 inches are expected.
The cold front blasts through overnight Wednesday bringing us back to normal late January/early February temperatures, 30s-40s for highs and 20s for lows. A series of relatively weak “Alberta clipper” type disturbances will dive at us from the northwest over the weekend. Each one will bring a chance of light snow or snow showers, especially west of the Blue Ridge, from Thursday through at least Sunday. The first arrives Thursday night into Friday, and another may push through on Saturday. Don’t expect a ton of snow, but it’s possible a dusting could be laid down even east of the Blue Ridge with one or more of the clippers.