As Kelli mentioned yesterday, a line of strong to severe storms will push through South Central KY this evening and into the overnight hours. Previously, the Storm Prediction Center placed Bowling Green in an enhanced risk for severe storms, but BG has been downgraded to a slight risk as of this morning. However, that does not mean you can let down your guard! Let’s walk through the components for severe weather and which of these conditions we expect to have today and tonight.
For strong storms to develop, one should look for 3 big things: moisture, lift, and instability. A fourth ingredient – wind shear (speed and directional) – provides additional support for the development of severe storms, specifically supercells and possibly tornadoes.
12Z NAM showing DPs increasing throughout the afternoon and evening to values in the low to mid 60s. – Courtesy Pivotal Weather
Ahead of the storms, we’ll see moisture and warm air advect from the southwest. The dew point temperature and air temperature in Bowling Green right now (1pm data) are 53 and 64 respectively. A warm front will be pushing into our area during the early evening hours and increase our those values into the low 60’s and upper 60’s respectively. One thing reducing the potential for additional lift attributed to warm air temps is cloud cover. Because of the decent cloud cover we have experienced throughout the morning to noontime hours and the additional cloud cover we will have during the peak heating hours, this will keep our temperatures cooler and reduce (but not eliminate) at least one ingredient for severe weather. Currently, we’re experiencing a clearing trend, so the sun is having its first opportunity to add more significant energy to the lowest levels of the atmosphere.
12Z NAM showing MUCAPE values around 500 J/kg just ahead of the arrival of the QLCS. – Courtesy of Pivotal Weather
The amount of instability typically required for severe storms can vary greatly depending on what time of year the storms occur. Summer time storms require massive amounts of CAPE (convective available potential energy), but storms during the Fall don’t need values nearly as high. Expected CAPE for this event will be around 500 J/kg, which is enough to fire up some storms; however, if storms develop ahead of the Quasi-Linear Convective System (QLCS) that we’re expecting, they will consume some of the required CAPE to create a severe environment for the main line of storms.
12Z NAM depiction of rain (first frame at 3pm, last frame at 3am). – Courtest of Pivotal Weather
One final thing to consider is the amount of rain that will fall during this relatively short period of time. Models are pointing to a widespread area of an inch of rain, but many places could receive upwards of 2+ inches if they experience storms ahead of the QLCS. Be extra careful if you are out and about during the late night/extremely early morning hours. Turn around, don’t drown.
With all of this in mind, there will be sufficient moisture and decent CAPE (instability) and decent lift to create severe weather, but lift and CAPE will be reduced if cloud cover over our area remains throughout the day and if storms fire off ahead of the QLCS. Therefore, make sure to tune in to your favorite weather source tonight, whether that’s TV, radio, or social media. Also, stay safe by having a plan for your entire family. This includes everyone knowing where to take cover (an inner room on the lowest floor of whatever building you’re in with no windows) and having a weather radio on hand.
Weather concerns: mainly winds greater than 60 mph, slight chance for a tornado, flash flooding possible, no significant large hail threat for our area.
For updates during the event, you can follow any of these WKU Storm Team social media accounts:
Facebook: WKU Storm Team
Twitter: @wkustormteam
Instagram: @wkustormteam