Strong front brings storm threat, much colder temps
After a mild Saturday, there will be an overnight threat for damaging wind gusts followed by a 30 – 35 degree drop in temperatures.
Today and Tonight: On Friday, a warm front will lift through the region bringing milder air and increasing clouds. Expect a high temperature in the upper 60s with southeast winds of 5-10mph. Overnight will stay mild with lows in the mid 60s.
Up Next: Saturday will mostly cloudy and uncharacteristically warm. You may find a stray shower, but of the two weekend days—Saturday is a much safer bet for outdoor activity. A strong cold front will move into the area after midnight into Sunday Morning. Immediately along the boundary, there will be a brief window of opportunity for severe storms, with damaging wind gusts being the main concern. Soon after the line of showers and storms, north winds of 10-15mph will blast much colder air into the area. Sunday’s high in the low 70s will occur during the early morning hours ahead of the front. Once it passes, temperatures will fall through the day with afternoon readings in the low 40s! By Monday Morning, lows will be in the low 30s. Clouds will be more prevalent than sun into early next week, and an isolated shower or two will be possible as well. This will keep Monday and Tuesday cold with highs struggling to leave the upper 40s.
THE SCIENCE: As a surface high pressure system moves east on Friday, return flow will commence allowing significant warming. A warm front will quickly lift through the region, increasing clouds. If a shower can develop, it will most likely stay west of the Baton Rouge area because the atmosphere will be too stable locally. A deepening trough in the Western United States will result in deep layer southwest flow and thus a breezy and mild Saturday. Highs will be well above average, possibly approaching 80 degrees. At this time, forecast models are suggesting a stray shower or two, but given the still shallow moisture field and weak instability, nothing widespread is expected. A strong cold front will then move into the area on Saturday Night and this will present a rapid change in the weather. Along the boundary, a squall line will develop due to ample lifting. While instability will remain fairly weak, the frontal forcing will be able to overcome this and some deeper clouds should develop. There will be a small window of opportunity for this squall line to produce severe weather. The Storm Prediction Center echoes this notion, pointing to damaging wind gusts as the main concern immediately along the boundary. However, mid-level relative humidity forecast charts are in a marginal 60-80% range and thus negative buoyancy doesn’t look all that impressive. Meanwhile, storm relative helicity is forecast to be on the lower end of severe criteria. Needless to say, it’s hard to argue with a 30-40 degree temperature gradient and thus the “slight risk” is warranted. The front will push through on Sunday and northerly winds of 10-15mph will drive much colder air into the region. Sunday’s high in the low 70s will likely be registered at midnight or just beyond with cold air advection moving thermometers into the low 40s by late afternoon. The forecast for next week is uncertain—and that puts it mildly. Whereas earlier runs of the GFS and ECMWF were suggesting a stalled front and overrunning precipitation, albeit both were ever at odds, now they have shifted to a drier solution. The deep layer flow will be a bit more west, southwest than initially thought and this should cut back on precipitation output. However, with a warmer component to the upper flow compared to the much colder northeasterly flow at the surface, a thick low to mid level cloud layer will be able to develop maintaining chilly and gloomy conditions. And still, a few showers can’t be ruled out but it won’t be widespread or steady. Some moderation can be expected by Wednesday as a shortwave trough kicks through the region with another round of showers.