More rain will cause runoff, flooding issues to continue
Due to another upper level disturbance, moderate to heavy showers and thunderstorms affected the area Thursday morning. Rain amounts have been wide ranging over the last several days, but some localized totals upwards of 5 inches have occurred. In fact, just yesterday there were isolated pockets with over 2 inches of rainfall. Such locations will not be able to tolerate much additional runoff and may experience flooding issues as a result. Remember not to drive across a flooded road. At minimum, you risk stalling out; at maximum you risk becoming stranded or swept away.
Today and Tonight: Thursday will bring another round of rain and thunderstorms. With morning activity flaring up, showers and thunderstorms will limit warming and subsequently activity during the second half of the day. As the unsettled weather eases off, some breaks of sun are possible with highs struggling for the low 80s. Isolated showers could linger into the evening with otherwise mostly cloudy skies and lows in the low 70s.
Up Next: Scattered showers and thunderstorms remain in the forecast through Monday. 13 Parish and 3 County forecast area rain coverage should be in the 40 to 60 percent range any given day. A little more sun is anticipated than earlier in the week and therefore highs should climb into the mid 80s. Lows will stay in the low 70s. On Monday night, a cold front will move into the area which will eventually sweep away the unsettled pattern and some of the humidity for the middle of next week. As of now, Tuesday looks to be the day of transition. Through Tuesday, an additional 2-4 inches of rain is anticipated with locally higher amounts where isolated downpours occur. Because a general 2-4 inches has already fallen, flooding of roads and area with poor drainage can be expected to pop up pretty quickly. Continue to drive responsibly. Also, report any flooding, with photos if possible, to firstname.lastname@example.org or @WBRZweather on Twitter.
The LSU Softball team competing in the College World Series in Oklahoma City will have to dodge showers and thunderstorms for their 1:30pm start slated for Thursday. However, rain chances look lower than earlier in the week. No better luck is expected for the LSU Baseball team hosting the NCAA Regional in Baton Rouge. With scattered thunderstorms in the forecast, several delays are possible through the weekend.
THE SCIENCE: A dissipating surface trough will factor into shower and thunderstorm development through Thursday. A discrete wave, noted on the water vapor imagery, is responsible for the second morning round of rain and storms this week. Once this wave exits east, the latter half of Thursday should be calmer due a rain cooled and briefly stabilized atmosphere. In the absence of these upper disturbances, daytime heating will take over as the key factor in igniting rounds of showers and thunderstorms. Through the weekend, the atmosphere will remain moist and unstable so as afternoon temperatures reach the low and mid 80s, scattered to widespread showers and thunderstorms are expected for the remainder of the week. Precipitable water values in the 1.75 – 2 inch range will be sufficient for locally heavy rain and possibly some nuisance flooding—especially since daily rain has caused saturated grounds and therefore runoff issues. Daily rain coverage will vary through Monday but should not dip below 40 percent for the 13 Parish, 3 County forecast area. At the same time, no washouts are expected. The bottom line is this—during the late spring and early summer, if there is any kind of disturbance from the surface to the upper levels, enough moisture and instability is available for widespread activity like this. An upper level ridge or surface high pressure is ultimately needed to taper the showers and thunderstorms. A cold front is expected to move into the area early next week providing a break from the highly unsettled regime. A slight reduction in humidity appears possible as well.