Severe weather shifts to Mid-Atlantic, after MS tornado
Tuesday, January 23, 2018, 10:07 - After last week's snow and cold, temperatures have rebounded across the much of the South and East to more seasonal values. While the warmth is a welcome break, it also provides the right atmosphere for severe weather development.
Following a very active start to the week (by January standards) in the central/southern Plains and Mid-South, with a total of 12 tornado reports over the last two days, forecasters are now watching for the development of thunderstorms for the Mid-Atlantic and South Florida.
There is a marginal threat for 2 areas today: the East Coast including North Carolina up to and including New York City and Connecticut, and the south being South Florida. We pick up the story below:
- Severe weather is likely on Tuesday with a marginal threat from the SPC as of Tuesday AM. The storms will be ongoing through the afternoon and evening.
- Damaging wind gusts are the primary threat . Tornadoes and hail are very unlikely
- Updates on weather warnings can be monitored on the ALERTS page of our website or get alerts sent to your phone with The Weather Network app
Click play to watch below: Severe storm track
The storms are associated with a Colorado low that pushed over the central Plains - bringing heavy snow and blizzard conditions to the Upper Midwest - which eventually collided with milder, moist air from the Gulf of Mexico -- thus triggering the thunderstorms this week.
Scattered thunderstorms, with sporadic/isolated severe gusts will be possible through the afternoon and perhaps into early evening across south Florida and the Mid-Atlantic region (see below).
The threat for damaging winds was stronger in the morning, but residents should continue to be on alert for isolated severe gusts throughout the day Tuesday.
While thunderstorms will fully push out by Tuesday night, flooding may remain an issue due to ice jams across portions of the Northeast.
What was the driver for this spell of severe weather?
Thanks to the upper-level system supporting the Colorado low, winds at middle and upper levels of the atmosphere over much of the south will be out of the southwest Monday. Simultaneously, the wind flow in the lowest levels of the atmosphere in this region will be directed from the south, right off the Gulf. Southerly surface winds not only supply thunderstorms with moisture from the Gulf of Mexico, but this also creates for a situation in the atmosphere that meteorologists refer to as "wind shear," where the wind direction twists with height.
Wind shear is a meteorological parameter forecasters look for to assess the risk of severe weather as it helps to develop 'healthy' thunderstorms - ones that are large and long-lasting, and have the potential to generate severe weather.
Instability refers to the tendency that air parcels near the surface have in order to rise vertically throughout the atmosphere. The higher the instability - the greater potential for severe thunderstorms.
Rainfall totals in excess of an inch or slightly more will be possible through Thursday (see below).
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With files from The Weather Network meteorologists Jaclyn Whittal, Ross Giarratana, and Caroline Floyd