Strong to Severe Storms Possible Ahead… Wednesday AM Update – 8:30am #alwx @wvua23
January 18, 2017 Leave a comment
Good Wednesday morning! We’re still carefully watching forecast trends over the next several days, as we deal with 2 rounds of heavy rain and storms across Alabama. Both rounds have the potential to bring strong to perhaps a few severe storms. Round 1 comes in Thursday afternoon, with a low end risk of strong to severe storms. Round 2 comes over the weekend; in-fact, the weekend event could come in 2 waves of storms. One on Saturday and a second wave of storms on Sunday.
Above is the 500mb vorticity look at the shortwave trough coming in Thursday afternoon. The trough goes slightly negative tilt and will provide plenty of uplift over Alabama. The amount of instability, uplift and wind shear does support a risk of strong storms, with isolated severe storms. Given the amount of rain expected to develop and the forecasted nearly saturated atmosphere, that may limit the risk. Anytime after lunch Thursday into Thursday night, there is a risk of heavy rain, gusty winds and an isolated, small spin-up tornado. Large hail is not expected and the flooding risk is low Thursday afternoon into Thursday night. That wave will move to the east late Thursday night, but cold is not associated with this round.
Above is a look at the weekend system. As you can look and compare this one with Thursday’s event, the weekend setup is much more impressive in terms of uplift and dynamics involved. The upper air trough goes negative tilt, which will provide strong uplift in our local area. Models are hinting at a small piece of energy kicking out ahead of the main trough Saturday afternoon into Saturday night, which may produce a risk of strong to severe storms across Alabama. While that is in question, it is a distinct possibility, so be alert through the day on Saturday. It is also possible for Coastal convection to develop and limit the risk of severe weather on Saturday, as that tends to block the inflow of unstable air into central Alabama. As we get closer, we’ll have a much better understanding of a time-line and threat category.
Sunday will bring another wave of rain and storms, as the main trough passes through the area. Depending on what time the front reaches central Alabama will greatly determine how serious the severe weather threat becomes in our area. Midday to early afternoon surface heating would drive instability much higher, ahead of a very impressive storm system. If the front passes through Sunday morning, that could reduce the risk of severe storms on Sunday somewhat, plus, the possibility of coastal convection could also limit the risk on Sunday. Again, as we get closer to the weekend, we’ll be able to give you a much more clear picture of what will happen. There is a real possibility this event could become a serious threat, or it could be a limited risk due to some limiting factors discussed above. Keep checking back for updates…
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WVUA Chief Meteorologist