Pop-up pattern transitioning into widespread showers
The weekend will begin a fairly active period of showers and thunderstorms that will carry into early next week. Bigger changes to the precipitation pattern and temperatures are expected after that.
Today and Tonight: Again on Friday, high temperatures will make it into the upper 80s with plenty of humidity. Partly sunny skies may give way to a stray shower or thunderstorm, especially during the midday hours. 13 Parish, 3 County forecast area rain coverage should not exceed 20 percent. Winds will remain southeast at 10mph. The softball regional at Tiger Park this evening should be rain free, but will be warm and sticky. LSU takes on Fairfield at 5:30pm. Then, overnight low temperatures will stay mild and muggy in the low 70s.
Up Next: Saturday will remain warm and humid with highs topping out in the mid 80s. A flare up of showers and thunderstorms will occur during the late morning and afternoon hours with slightly greater coverage and intensity. 40 to 50 percent of the WBRZ Weather forecast area will receive rain with an outside chance at gusty wind or hail too. On Sunday, a cold front will move into the region bringing widespread showers and thunderstorms. Outdoor events should anticipate being diverted inside at times. As is typical with warm season storms, some could produce 1 to 2 inches plus of rain. Another round of showers and thunderstorms is marked for the beginning of next week which will lead to cooler temperatures and lower humidity by the end of next week.
Runoff from rain in the local area will not make it into the rising Mississippi River. The highest crest in several years is expected for “big muddy” in Baton Rouge. Here is what to expect.
THE SCIENCE: An increasingly shallower atmosphere and deep layer southwest flow will result in more moisture and instability through the weekend. A pocket of positive vorticity advection (PVA) riding above a steady return flow should be enough to kick out diurnally forced showers and thunderstorms on Friday. By Saturday, another pocket of PVA will move over a more saturated and unstable atmosphere leading to more coverage in afternoon showers and thunderstorms with slightly greater intensity. A “marginal risk” of severe weather from the Storm Prediction Center is posted for isolated hail or gusty wind. Temperatures will still be able to reach the upper 80s in most locations before any activity flares up. Dew points will be very high, keeping overnight readings in the low to mid 70s. On Sunday, a cold front will move into this air mass and the consequential uplift will generate more widespread showers and thunderstorms. The front will be slow to move into the Gulf, as is typical this time of year with warming water temperatures fighting off the boundary. As waves of energy aloft move over the front, several rounds of showers and thunderstorms are expected to develop. Precipitable water values in the 2-inch range will mean that downpours will be possible with any thunderstorms. Many locations in the forecast area could pick up a quick inch or two of rain. Forecast models have not agreed on the scenario for next week but at least now there is a general idea that the front will slide south of the area on Monday, holding higher rain chances early and along the coast. Then, a second upper level trough will move from the Midwest into the Ohio Valley sending another cold front toward the Lower Mississippi River Valley. This system will likely result in another round of widespread showers and thunderstorms on Tuesday. While this front looks a little more potent and progressive, the associated trough is also positively tilted so it is just a little too early to tell if severe weather will be an issue. There is good model agreement that slightly cooler than average temperatures and lower humidity will follow this front for the end of next week.