UPDATE: heavy rain prompts flash flood warning in Baton Rouge
***FLASH FLOOD WARNING*** for East Baton Rouge has been extended until 2:30 p.m.
***FLASH FLOOD WATCH*** for the entire forecast area except Pointe Coupee, West Feliciana Parishes and Wilkinson County until 6 p.m.
Today and Tonight: Heavy thunderstorms will continue into the afternoon. Localized flooding will occur as some locations have already received 2-3” of rain with an additional 1-2” possible. Avoid driving through water on roads and move away from catch basins and drainage canals with rising water. River flooding IS NOT a concern at this time. The risk for severe weather remains, albeit low, as a few storms could produce gusty wind—especially in the afternoon. Temperatures will be in the upper 60s to low 70s with south winds of 5-10mph. Action will diminish overnight with lows around 60 degrees.
The National Weather Service Storm Prediction Center as placed the entire forecast area under a *marginal risk* for severe weather. This means isolated severe storms are possible within the forecast area. On a scale of 1 (lowest) to 5 (highest) severe weather threat, this event is a 1. Another way of describing the threat is that there is a 5 percent chance of experiencing severe weather within 25 miles of a given point in the risk area.
1) Downpours – heavy rain will occur with storm cells embedded in a larger area of precipitation.
2) Gusty Wind – in storms that turn severe, wind gusts could exceed 58mph.
3) Isolated Tornadoes – ingredients are not ideal, but enough wind shear in the atmosphere means that a tornado cannot be ruled out.
3-5” of rain could fall anywhere within the 13 Parish, 3 County Forecast Area—especially where the heaviest storms occur. At minimum, all locations will receive 1” of rain.
Estimated Timeline: Rain will continue to be widespread through mid-afternoon. The greatest risk for severe storms will be in the afternoon hours before a weak cold front kicks through the region. Clouds and lighter rain may last as late as evening; however, impact weather will be over by then.
Impacts: Areas of heavy rain may make driving difficult up to the early evening commute. Loose, outdoor objects could be blown in the wind –including any straggling holiday decorations. While the risk for a tornado is appreciably lower than in past events, we’ve seen “lower risk days” produce. Even a low risk is still a risk.
Actions: Of utmost importance today—remember turn around don’t drown. Very shallow moving water is enough to knock a person off their feet and just a few inches can float a car. Do not drive across flooded roads, at the very least, you risk stalling out and becoming stranded. Monitor the forecast. Stick with the WBRZ Weather Team on Facebook and Twitter and catch forecast on WBRZ News 2 for updates through the day. The *free* WBRZ WX App. sends push notifications to mobile devices if a watch or warning is issued for your location. Remember, a watch means “conditions are favorable, and a particular threat could develop” and a warning means that “threat is happening and you should take action immediately.”
Up Next: Partly sunny skies and mild temperatures are anticipated for Friday before another threat for strong thunderstorms shapes up overnight and into Saturday. Between Thursday and Saturday, the WBRZ Weather Team is placing a greater emphasis on the Saturday Morning threat which brings a higher risk for severe weather. Storms will end by Sunday though some showers could linger with sun back by Monday. Temperatures will cool Sunday and Monday, then briefly climb mid-week before a more significant shot of cool air arrives by the end of next week.
THE SCIENCE: An area of low pressure along the tail end of a decaying front will guide another “cold” front through the area Thursday—a boundary that will simply separate very humid air and mild air. An upper level shortwave moving from the Mid-South northeastward toward the Great Lakes Region will work with this front to enhance precipitation development through Thursday before both exit the region. Showers and thunderstorms will be ongoing Thursday Morning as column moisture continues to increase. Any thunderstorms could be heavy rain makers with atmospheric moisture much higher than usual for the time of year. As the front approaches by afternoon, a few stronger thunderstorms are possible. The severe weather parameters are very marginal, with forecast models suggesting CAPE values under 500 j/kg and 0-3km helicity under 200 m/s – both of which fall below levels typically needed for severe storms. Giving some respect to the f4ront and unseasonably warm air mass, the Storm Prediction center will carry a “marginal risk” of severe storms for our area. Perhaps a bigger story Thursday could be the slow moving area of precipitation that could produce an inch or two of rain. Greatest impacts to the area could come in the form of messy roads for the morning and possibly afternoon commutes. Friday will be briefly quieter and still mild before a deepening trough sends another cold front toward the area on Friday Night sand Saturday. This go around, models peg much higher instability and shear for the area and thus the severe risk is considerably higher. A warm front positioned along the Gulf Coast and strong vorticity at 500mb moving from west to east across the Coastal Plain sets up an environment favorable for gusty squall lines. Lift and shear created by the boundary allow storms to continue propagating forward. Current forecast models run the key ingredients and precipitation field through the area around 12z Saturday meaning a per-dawn to mid-morning timeframe appears most likely at this point. There is some model uncertainty as to how the second half of the weekend will unfold. A thermal trough could hang on Sunday with clouds and lingering showers possible. By Monday, sunshine and cooler temperatures are expected. A brief warmup may occur Tuesday and Wednesday before a more significant and longer lasting cool spell arrives by the end of next week.