Overnight storms, stronger system possible Sunday
The next five days will bring warming temperatures with two threats for severe weather—particularly Sunday.
Today and Tonight: Increasing humidity will be noted today. Look for partial sun and a stiff south wind of 10-20mph pushing high temperatures into the mid 80s. A cold front will move into the region after dusk with showers and thunderstorms. As the storms arrive, a few could be strong, especially north and west of Baton Rouge. Gusty wind will be the main threat. Because this will be a nighttime event, remember to have access to alerts while asleep.
Up Next: Showers will wrap up before dawn on Thursday morning as temperatures steady in the low 60s. Despite a cold front passage, no change to the local air mass is expected. Highs will be in the mid 80s on Thursday with readings near 90 on Friday and Saturday. Morning lows will be particularly nasty in the low 70s. A pop-up shower or thunderstorm is possible. By Sunday, a more significant cold front will move into the area with a greater risk for severe weather and even heavy rain. Stay tuned to this portion of the forecast as all threats are on the table at this point. Behind this, cooler air will arrive on Monday.
THE SCIENCE: After a warmer and more humid day, an upper level trough and associated cold front will move into the area tonight. As of now, a slightly negative tilt, moderate instability and some shear would suggest the possibility of a few stronger thunderstorms. Parameters should link up and peak right around midnight in the northwest portion of the forecast area on a corridor from New Roads to Liberty. This is where the Storm Prediction Center (SPC) has highlighted a 2/5 or “slight risk” for severe weather with gusty wind and an isolated tornado being the main threats. Precipitation is expected primarily during the overnight hours, ending on Thursday morning. On the other side of the front, winds will quickly shift back to the south meaning no sensible cool down is expected. In fact, warmth and humidity will increase for the end of the week with some locations approaching 90 degrees on Friday and Saturday. Daytime heat may induce an isolated shower or thunderstorm. The second and greater threat for severe weather will come this weekend. On Sunday, a deep trough will move across the Midwest and Central Gulf Coast with an accompanying cold front at the surface. Positive vorticity advection ahead of the trough and the front will greatly enhance omega as the system pushes through. Forecast model parameters have lifted index values maximized between -6 and -8 on Sunday Morning. CAPE values will be between 2,000 and 2,500 with storm relative helicity on the order of 250-300 m/s. In addition, the atmosphere is expected to be very rich with moisture as precipitable water tops out around 1.9 inches which is near the record for April 30. At this time, damaging wind and heavy rain would seem to be the primary threats but no mode of severe weather can be ruled out. Again, all of this is preliminary, but the SPC does hash out a portion of Central Louisiana and South Mississippi for the possibility of severe weather. We will need to monitor these trends as the weekend nears.