Here's what we know: parts of the Southern Plains and northern Gulf Coast are all but certain to receive excessive rainfall in the coming days. The devil lies in the details. It's difficult, if not almost impossible to pinpoint which areas will be hardest hit but we're gradually getting a better idea of where the greatest threats may lie.
Locally, we can expect scattered showers and a few t-storms to arrive by Tuesday afternoon, but neither flooding rains nor severe weather is anticipated in this initial round of wet weather. Those threats should remain to our west on Tuesday.
Our latest model runs have even started to indicate a somewhat slower arrival of the most active showers and t-storms, perhaps holding off until late Wednesday or even Thursday. It's during this timeframe though that severe weather appears to be possible along with our first real threat of locally heavy rains. The Storm Prediction Center does have areas from near Baton Rouge westward under a 'Slight Risk' of severe weather during this time, with a lower 'Marginal Risk' east of Baton Rouge.
The biggest threat to the greatest number of people during the remainder of the week will be heavy, potentially flooding rainfall. In a modestly encouraging trend, our last couple of rounds of computer model guidance have trimmed back forecast rain numbers. However, we still think widespread totals of 3" to 6" will be common in the WAFB viewing area through Saturday, with the potential for much higher amounts in localized areas. As it stands right now, a greater threat appears to be for areas near the Louisiana/Texas line extending northward to the ArkLaTex.
While the greatest threat does appear to be to our west, the weather pattern expected later in the week will favor the development of 'training' bands of t-storms -- clusters of storms moving over the same areas like train cars moving along a track. Anyone unfortunate enough to caught underneath one of these bands could easily pick up rains in excess of the 3" to 6" we're currently forecasting on average across the area.
With the expected heavy rains, we'll also have to monitor rising river levels later in the week. Additionally, persistent southerly winds mean that coastal flooding could be an issue in spots. Those southerly winds would also result in water backing up in the lower reaches of the Amite and Tickfaw river basins, slowing the ability of rain water to drain into Lake Maurepas.