Strong to Severe Storms Sunday Night – Thursday Eve Weather Thoughts – 9:30pm #alwx @wvua23

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Good Thursday evening! Here’s an update on the potential for strong to severe storms Sunday night across Alabama. Models have slowed the arrival time some, with storms reaching west Alabama just after sunset. The image above is off the 0z NAM, showing simulated radar. This is valid for 9pm Sunday night, and it’s got the leading edge of the QLCS (organized line of storms) reaching the Jasper, Tuscaloosa, Greensboro and Demopolis area. The line itself will be moving east fairly fast and weakening as it tracks across the state. The only threat of anything becoming strong or severe will be right on the leading edge of the squall line. Once the front edge of the line passes east of you, the risk of strong to severe storms will rapidly end within an hour after beginning in your location. Expect rain to continue for a few hours after the line first impacts your area.

Given the low amount of surface based instability and weak lapse rates, the risk of severe weather will remain relatively low with this system, however, the parameters still remain marginal for some issues with damaging winds and maybe a spin-up tornado or two Sunday evening and Sunday night, mainly 5pm to 12am. While the threat does not appear major at this time, please make sure you have a source of severe weather information incase a dangerous storm approaches your neighborhood. If we get a tornado warning in our area, tune into WVUA23 for live coverage. Since we haven’t had a severe weather threat in a long time, now is a good time to review your plan incase a severe storm were to track over your area.

Below is your surface based CAPE for 9pm Sunday night. This is the instability storms need to become strong to severe. There’s just not much instability at all, which is not uncommon for a late fall, early winter event in Alabama. CAPE according to this model (NAM), is generally at or less than 200 J/Kg, which is really low to cause severe weather issues. With this setup, you really need values to approach 800 to 1,000 J/kg before dealing with widespread or major severe weather issues. Fortunately, models continue very consistent on the idea of very low instability with this event. However, if instability rises, the risk will increase. If instability decreases even more, the risk will decrease even more.

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Below is the wind speed and direction at 850mb, or nearly 5,000 feet above the ground. Winds over our entire area are between 50 and 70kts, which is incredibly strong. This is one reason I think damaging winds will be a risk. It won’t take much to get these winds to the surface within the line of storms. I think there will be a few spots that get a damaging wind gust over 60mph. Not everyone will get wind damage, but most spots will get some strong winds along the line itself. Fortunately instability isn’t high, otherwise a strong low level jet like that could cause some widespread issues.

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Below is the trough axis at 500mb. This shows a negatively tilted long wave trough moving into the area Sunday evening and Sunday night. This adds to the intense uplift to the atmosphere.

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Again, I don’t expect this to be a major severe weather event, but the parameters are there for a line of strong to isolated severe storms to push across the area Sunday evening and Sunday night.

Join us live on WVUA23 weekdays at 5, 6 and 10:00 P.M. and weekends at 10PM for the very latest on your news, weather and sports.

Richard Scott
WVUA Chief Meteorologist
rscott@wvua23.com
Twitter: RichardWVUA23
Facebook: WVUA23RichardScott

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Very Warm Days Ahead… Severe Storms Sunday Eve/Night… Thursday Forecast Update – 4pm #alwx @wvua23

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Good Thursday afternoon! Today has featured a mix of sun and clouds with very warm weather for this time of the year. Upper level ridging has taken over the southeast and will continue to build up ahead of an advancing long wave trough to our west. Expect some foggy areas tonight, with temperatures only dipping into the upper 50s. That’s close to our average high for this time of the year!

A light south breeze will continue to pump moisture and warm Gulf air into the state on Friday, with highs in the middle 70s, especially along and south of I-20. We’ll reach the upper 70s on Saturday and Sunday, with some spots over central and south Alabama reaching the 80 degree mark. This will be approaching record highs for this time of the year. Expect lows in the upper 50s to lower 60s at night, which is very mild for mid December.

The next storm system we will be watching careful arrives Sunday evening and Sunday night. Most of Sunday will be dry and very warm, but storms will reach west Alabama sometime during the late afternoon or evening hours. It’s possible we remain mostly rain-free until after sunset Sunday, but models are still iffy on the exact start point. Since we’re still a few days out, timing may change some. Storms will likely reach far west Alabama after 4pm Sunday. Models indicate most parameters will support the risk of severe storms, including isolated areas of damaging winds (60mph or higher) and an isolated weak, spin-up tornado or two along a QLCS (squall line). The main limiting factor is the amount of surface based instability. It doesn’t take much instability this time of the year to cause problems, especially given the strong uplift and wind shear involved. Lapse rates are also pretty weak, so that’s another limiting factor for a big severe weather event.

The line itself will move through pretty fast, so once the active weather starts in your area, it will pass east of you fast, then it will rain for a while through the rest of Sunday night. Storms will be gradually weakening as they track east across the state Sunday night. The risk of severe weather in east Alabama is a good bit lower. Changes are possible with this system, so it is important to keep checking back with us for updates as we get closer. It is not uncommon to have severe weather in the late Fall. This is our secondary tornado season for the year.

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Join us live on WVUA23 weekdays at 5, 6 and 10:00 P.M. and weekends at 10PM for the very latest on your news, weather and sports.

Richard Scott
WVUA Chief Meteorologist
rscott@wvua23.com
Twitter: RichardWVUA23
Facebook: WVUA23RichardScott