Posted: Apr 28, 2014 8:37 AM by Meteorologist Josh Eachus
Updated: Apr 28, 2014 8:37 AM
The setup: A deep upper level low continues to spin leeward of the Rocky Mountains. Smaller lobes of energy are rotating around this low and serving as driving mechanisms for areas of showers and thunderstorms from Texas all the way to the Ohio Valley. There is also a surface cold front in Northwest Texas that has shown little eastward advancement over the last 24 hours. Warm and humid air continues to pump inland from the Gulf of Mexico. For these reasons, areas from the Midwest to the Southeast are primed for severe weather. There is an area from Northeast Louisiana to Northern Mississippi and Southwestern Tennessee where confidence is much greater that there will be widespread severe weather. Locally, areas on a line from Baton Rouge to McComb and points northwestward are under a risk for severe storms while locations from Gonzales southeastward to the coast have may still find a few hefty storms.
The "catch 22" with today's forecast is that much of the upper level energy, or vorticity, is expected to stay north of our area. Forecast models are struggling with this notion, some showing very little shower and storm development in Southeastern Louisiana while others portray rounds of showers and storms. However, there is abundant instability and the upper level wind profiles are favorable for severe weather. Low level winds are strong and southerly while mid-level winds are stronger and southwesterly. Thus plenty of speed and vertical wind shear are apparent to allow thunderstorm cells to rotate. Therefore, even if today's storm coverage is isolated, the few showers and storms that do develop could quickly become powerful. An isolated tornado is possible today and tonight while by Tuesday Morning the storm threats transition to damaging wind and torrential rain.
The forecast: Monday will be similar to Sunday with mostly cloudy skies, windy, warm and humid conditions. Highs will top out in the middle to upper 80s with dew points near 70° meaning that it will feel very humid. Winds will blow stiffly out of the south-southwest at 15-20mph with some gusts exceeding 30mph. Isolated showers and thunderstorms will be possible from mid-morning onward. More scattered activity is expected during the afternoon and into the overnight hours. Expect activity to become more noticeable after the 4pm hour. It is the later batch of storms that have the possibility of getting rambunctious. Isolated tornadoes and damaging winds will be the main threats through evening while overnight and early morning storms could be heavy rain makers. Nighttime temperatures will again stick near 70°
A final pop of strong to severe storms will impact the area on Tuesday as a cold front finally clears the region.