ROANOKE, Va. – This week has a very spring-like feel to it in more ways than one. First, we start with near-record warmth in the area Monday afternoon. Then, we begin tracking a very strong storm system moving through the U.S.
While we’ll see a few showers Tuesday and Wednesday, these likely won’t be anything severe. The better chance for severe weather will be around parts of Texas, Arkansas and Louisiana. As the system dives into the Gulf and grabs more Gulf moisture, that severe threat shifts east toward the Deep South Wednesday. Finally, the severe threat stretches from Florida to the Carolinas (and perhaps southern parts of our area) Thursday into Thursday night.
When forecasting, I like to take a top-down approach. We first look at the upper levels of the atmosphere, and this reveals a very deep system. It’s a system that stretches into the Gulf, grabbing that moisture and flinging it our way Thursday.
At the surface, we see a very strong cold front responding to the upper level system. A strong low pressure system rides that front, which acts to not only grab the moisture at the surface but to lift it to a point where heavy rain can develop. This also creates a lot of wind shear (winds changing speed and direction from the surface to thousands of feet up). If there’s enough instability (storm fuel) to work with, this could create a damaging wind threat in southern portions of our area Thursday night.
WHAT IT MEANS FOR US
The more significant threat we see is the potential for flooding. Between Tuesday and Thursday, we could see anywhere from 2-4″ of rain (locally higher totals near the Southern Blue Ridge). With most of that coming Thursday, we’ll have to watch some rivers, streams, creeks and low-lying spots. Flash flooding isn’t out of the question when that much rain is in the forecast within a relatively short time window.
Once this system passes, remnant moisture and cold air will team up for mountain snow through Friday morning. Otherwise, it will be noticeable windier and colder throughout the day Friday.
Another disturbance is possible, trailing this main one. If that’s the case, a rain/snow mix can develop in some parts of our area Saturday night into Sunday morning.