Freezing Tuesday Morn; Severe Storm Saturday Night?

Everyone wants to know how cold it will get, and many think I’m ducking the question when I ask where they live. Tonight, when the wind is up, location (other than North- vs. Southshore) won’t matter much. The atmosphere will act like a well-stirred paint can. But tomorrow night when the winds become calm, huge differences between rural and more densely suburban areas will prevail. Because all on the Northshore will experience frost and we’re not talking a deep freeze for the many that dip below 32, it becomes a moot point: Place a blanket or plastic sheet over those annuals (or take them in) Monday afternoon when the wind dies down. You can then remove the covers on Wednesday. See my forecast discussion for more details.

Just as quickly as the cold air blows in tonight, it will blow out late Tuesday. Then, we’re in for three days of gorgeous sunny fall weather with highs in the 70s and lows in the low-mid 50s through Friday.

The next system arrives late next Saturday night and early Sunday. It has some of the classic earmarks of a cold front that could bring severe weather (high winds, tornadoes) to the lower Mississippi Valley. In the long-range, I look for fronts and upper air systems that bend back slightly to the NW, secondary low pressures areas that try to form in Western Louisiana or Mississippi north of us, and a secondary heavy precipitation maximum (look at those reds below) that shows a divergent “v” pattern. I see those in this forecast from the ECMWF forecast for Saturday night. The American GFS is similar and both models have flashed this off and on for the last five days.

Of course it’s too early to say for certain, and no one knows where this is most likely to happen in the South (could be central Mississippi ?), so we’ll keep an eye on it. But….did you know that we are more likely to see tornadoes in SE Louisiana in early November than in March or April? Reason: Gulf water temperatures are warmer than they are in the early spring.

The Foreca graphic shows the outlook well. Tonight, lows 35-40 everywhere on the Northshore. Tuesday morning, 26-28 will be common across rural areas while the more densely populated suburban areas (190 corridor in Mandeville-Covington, near Gause in Slidell, downtown Bay St. Louis as examples) could stop right around freezing. I don’t think you have to worry about pipes freezing. On the Southshore, 40s tonight, 38-41 tomorrow night — too warm for frost in the City, Metairie, or Kenner. Then, the warm up begins.

Date Low High Weather

Tuesday Nov 18 47 63 Sunny Low humidity

Wed. Nov. 19 48 65 Sunny

Thurs. Nov. 20 52 68 Sunny Increasing humidity

Fri. Nov. 21 56 72 Partly cloudy

Sat. Nov. 22 63 77 Scattered showers, humid

No frost or freezing weather in sight, but my long range guru thinks that cold weather will return in late November/early December.