12/22 – Brantly’s “Warmer Tomorrow, Big Cool Down Ahead” Tuesday Evening Forecast
High pressure will continue to slide to the east with southerly flow becoming established across the area tonight and Wednesday. Temperatures will be a bit warmer tonight with a light southerly flow and steadily increasing low level moisture. There could be some patchy fog later tonight but cloud cover should begin to enter the region after midnight into Wednesday morning hours which should limit cooling.
On Wednesday a longwave trough moves into the central United States with the base of the trough into south Texas. This scenario will setup southwest winds aloft with weak impulses initially by the afternoon hours. Increasing moisture and instability will also aid in a few showers or isolated thunderstorms developing out ahead of the main punch which is expected Wednesday evening into Wednesday night when a cold front approaches and then sweeps through the region around the early morning overnight hours.
There is a marginal risk for severe thunderstorms Wednesday 6 am ending Thursday 6 am for all of southeast Louisiana and all of the southern half of Mississippi. The Storm Prediction Center indicates that marginal instability and lapse rates don`t favor widespread convection. However…along the frontal boundary…a few cells may develop some rotation and therefore pose a marginal risk for damaging winds and possibly a tornado.
The threat of severe weather will end Thursday with rain having ended from west to east. High pressure will build back in with dry northerly winds. Much colder air will settle in as well the night before Christmas.
On Christmas Day…colder air will settle into the area and remain entrenched through much of Saturday. A upper level shortwave trough will move into the Lone Star State of Texas Saturday with low level southerly flow returning to our area. Rain chances enter the picture once again Sunday night into Monday as the next cold front sweeps into southeast Louisiana.