One down, one to go: higher severe weather threat tonight
The first threat for severe weather, fortunately, did not materialize on Monday Evening. The Baton Rouge area will once again have conditions favorable for strong thunderstorms overnight Tuesday into Wednesday. Stay in touch with the forecast and have access to alerts while you are asleep tonight via the WBRZ WX app. or NOAA Weather Radio.
Today and Tonight: Once again, a mild afternoon is ahead with temperatures stretching for 80 degrees. Some sun early will give way to increasing clouds into afternoon with a few showers and thunderstorms possible. Then will come another round of potentially strong to severe storms. A squall line is expected to approach the area during the evening and overnight hours bringing with it the risk damaging wind gusts and an isolated tornado. As of 6am Tuesday, forecast models suggested most of the action occurs from 10pm – 2am. Mainly for that period, the National Weather Service Storm Prediction Center has outlined an “enhanced risk” for severe weather in the WBRZ Weather forecast area from I-12 northward and a “slight risk” south of that. Showers and thunderstorms are expected to wrap up from west to east by dawn Wednesday with temperatures dropping back to about 60 degrees.
As a reminder, for the most immediate weather updates in Baton Rouge area, follow WBRZ Weather on Facebook and Twitter and take our live coverage with you on the WBRZ Weather app should it be necessary. Also, just because round one did not produce any severe weather on Monday, does not mean this one will be the same—all storm scenarios come together differently!
Up Next: Some sun may return as early as Wednesday Morning with high temperatures stopping in the mid 60s. Overnight will be much cooler with clear skies and lows in the low 40s. Thursday will bring abundant sun and a high in the low 60s followed by a repeat on Friday. The next chance for rain will come this weekend which figures to be mostly cloudy and therefore chilly—highs will struggle to leave the 50s!
The Tropics: The tropics are quiet and no development is expected this week.
Forecast Discussion: A deep longwave trough remains over the Midwest United States with another pocket of positive vorticity rolling through the mean flow. The strongest jet streak has settled farther north of the Southern Mississippi River Valley. A surface cold front is quickly advancing eastward at the base of the longwave trough which will be lifting northeastward to the Great Lakes region through Wednesday. As the cold front approaches the forecast area this evening, CAPE values are expected to be from 500 - 1,000 j/kg, a bit more unstable than in Monday’s episode. At the same time, helicity will remain high with values of 300-250m/s. Storm initiation will come later in the day and be benign at first. More organized action should be reserved for a squall line ahead of the front where the highest omega values will be found. With the squall line, damaging wind gusts would be of primary concern with an isolated tornado the secondary threat. High resolution models time out the most active period from 10pm – 2am. As the trough lifts away on Wednesday and surface high pressure builds in, skies will clear and northwesterly winds will usher in a cooler and drier air mass. Below average temperatures will persist into the weekend as the next weather system takes shape. At upper trough is expected to pinch off over the South Central United States leaving the local area on the active eastern side. Moisture return and disturbances in the deep southwest flow will likely result in at least one, perhaps multiple batches of rain. The baroclinic zone off of the South Texas coast could spark cyclogenesis with a surface low and associated fronts lifting northeastward through the weekend, though it appears as though the Louisiana Gulf Coast will stay on the cool side of this system and thus, severe weather is not a threat. Models DO agree on this scenario overall but DO NOT agree on timing at this point. The GFS has this playing out on Sunday while the ECMWF is faster and more drawn out with a wet pattern Saturday into Monday Morning. For what it is worth, the GEM is more on board with the GFS. We’ll fine tune this part of the forecast through the week.