Nice at the box, under the dome
Sunny skies and warm temperatures will continue through mid-week. The same dome of high pressure responsible for the nice, quiet weather pattern is also creating a stagnant air mass and resulting air quality issues. By Friday, the next cold front arrives with showers and thunderstorms followed by a Mother’s Day weather present.
Today and Tonight: Look for another nice one on Tuesday with continued sunshine. High temperatures should get a degree or two warmer in the upper 80s with southeast winds of 5-10mph. However, humidity will remain low. A perfect evening is in store at Alex Box Stadium where the Tigers play host to South Alabama. Nighttime thermometers will dip in to the low 60s with light, southeast winds.
The Louisiana Department of Environmental Quality is forecasting an Ozone Action Day for East Baton Rouge, West Baton Rouge, Livingston, Ascension, Iberville and Pointe Coupee Parishes with an AIR QUALITY ALERT in effect until midnight. Increased ozone will be unhealthy for sensitive groups. Active children and adults, the elderly and people with respiratory diseases such as asthma should avoid prolonged outdoor exertion. Through Tuesday, an upper-level ridge of high pressure over Louisiana will reduce atmospheric mixing. In addition, warm temperatures and sunny skies will enhance ozone formation, and calm to light southerly winds at the surface will inhibit air dispersion, allowing pollutants to accumulate. These conditions will lead to elevated air quality index (AQI) levels.
Up Next: The ridge of high pressures responsible for the sunny and gradually warming conditions will begin to slide east by Thursday. Additional humidity will be noted with some cloud development as well. By Friday, a cold front will come into the area with the next round of showers and thunderstorms. At this time, severe weather is not a concern. On the other side of that front, a return of very pleasant weather is in store for Mother’s Day weekend.
THE SCIENCE: An upper level ridge of high pressure is centered over the Central Gulf Coast. Surface high pressure is positioned in the northeastern Gulf of Mexico. The combination of sinking air aloft and calm wind sat the surface are promoting clear skies and minimizing atmospheric mixing. As a result, despite picturesque weather, air quality has taken a hit with increased ozone. The ridge will begin to break down by Thursday as an upper level low moves over Texas. This will develop a surface low pressure system and associated cold front. Ahead of this system, winds will turn around to the southeast bringing higher dew points and a bit more humidity. As a result of increased moisture, diurnal temperature ranges will decrease. So overnight lows will come into the mid 60s but afternoon highs will remain in the mid to upper 80s. A pocket of positive vorticity advection in combination with a crossing cold front should result in considerable uplift for the development of showers and thunderstorms on Friday. At this time, the positive tilt of the upper trough does not signal any immediate concern for severe weather. On the other side of the front, there will be a brief drop in dew points and temperatures resulting in a mostly clear and comfortable Mother’s Day weekend.