5/16 – The Chief’s “Humidity Returns” Thursday Morning Forecast
The old frontal boundary is stalled near the coast this morning and drapes inland near Terrebonne Parish westward to Beuregard Parish. The back end of this front will be the main area to watch later today as it gets brought back to the north and storms start to fire along it. Rainfall rates will intensify through the day along this boundary and should be most intense with a corridor of heaviest rainfall from near a line from Austin to DeRidder then up to McComb to near Hattiesburg over the next few days.
This boundary will also compartmentalize where severe storms will form. North of this boundary should be all heavy rain but there is the potential for large hail to the north of this boundary. The surface instability will be through the area this morning. The entire area should be unstable throughout the column before midnight tonight. This deep vertical instability should be evident by where the rain and storms begin to fire later today. Even though SPC has a marginal risk level for the area, it still warrants attention as conditions will be conducive for severe storms, just not to the degree that Fri is looking. The first wave moves out Friday morning and fast on its heals will be the next disturbance that should start developing near the Houston area Friday morning and quickly move ENE along this same boundary entering our area around 3 pm Friday. The next system will be right behind this one as the third round should develop somewhere between Houston and Corpus late Friday and move ENE at a very rapid pace entering the area around or just after midnight Friday night into Saturday morning. This final round should produce a very fast moving squall line producing severe wind speeds. We will need to see exactly where and the time this complex forms to pin down any discrete placement and timing locally. These Friday systems look quite volatile and will have a lot of energy to use in the form of almost every severe weather variable with all modes of severe possible. Models have been ever so slightly nudging this whole mess northward, but we are still quite confident that most of the area will see strong chances of heavy rainfall and severe storms at some point between today and early Saturday.
Even though the boundary gets left in place across the area Saturday, the surface low and upper weakness will move east, this will help alleviate the heavy rain and severe storm threat for most of the weekend. High pressure builds and moves east by the new week but ridges over the gulf coast through about mid-week.
