Nice day today, still mostly sunny tomorrow. Then the clouds start to roll back into the area on Tuesday.
That is when the wind flips back around to the south, too. And we start to usher in more Gulf of Mexico air. Looking at the reverse trajectories, by late Tuesday night and into Wednesday morning we are still just dealing with recirculated air in the lower levels.
The red and blue lines on the map above show the journey for air under about 5,000ft and the air up around 15,000ft is shown in green. So we have mid-level tropical air on top of recirculated subtropical air. But the left sice of the timeline on the graphic above does show the ascent that will be happening as it gets closer. Very general ascent like that is typical ahead of an area of low pressure.
And that is what we’ve got as we head through Wednesday and through Thursday.
The trajectory of our air is a bit different then.
That is when we start to pull in air from the Gulf, Caribbean and subtropical Pacific all at once. And this should be enough to set the stage for the potential for severe weather.
And, right on cue, the CIPS Analogs suggest the potential.
The CIPS Analogs, recall, looks back in time and try to find events in the past that looked like (in the atmosphere) what the models are projecting the upcoming event to look like. It picks out the Top 15 most similar-looking events. From there, it asks, “what happened?”
Above, on the left, is the percentage of the time that in similar situations there was at least one (1) severe storm. And above on the right is the percentage of the time that there was at least one long-track tornado.
The list of events looks like this:
That gives us a pretty good estimation about the outcome for the potential severe weather event that the model guidance is showing. Notice there are some very big events and some duds. So this upcoming threat isn’t a slam dunk by any means.
In this situation it looks like there will be two rounds of potential storms. The Round One will be with the warm front as it surges northward on Wednesday. Round Two will be ahead of and along the cold front as it presses through on Thursday. For the Southern MS/AL/LA region, the chance you see severe weather on Wednesday is lower than the chance for severe weather on Thursday.
Currently, the main threats on Wednesday will be brief heavy rain, lightning, wind gusts up to 50mph and hail up to the size of quarters.
Currently, the main threats on Thursday look to be brief heavy rain, localized flash flooding, lightning, wind gusts up to 70mph, hail up to the size of quarters, and a few tornados (up to EF-3 in strength)
Both of those ‘main threats’ may change in the coming hours and days as model guidance continues to get a better handle on what may – or may not – occur. If you wanted to break the severe threat down, hour-by-hour like above, it would look like this:
Notice that things are pretty much over by the time we get through Thursday evening. And that sets the stage for a nice weekend, again, too.
REGIONAL DAY TO DAY FORECAST
Today
Sunny. Highs around 60. Northwest winds 10 to 15 mph.
Tonight
Mostly clear. Lows in the mid 30s. West winds around 5 mph.
Monday
Mostly sunny. Highs in the upper 60s. West winds around 5 mph.
Monday Night
Partly cloudy. Lows in the lower 40s. South winds around 5 mph.
Tuesday
Partly sunny and breezy. Highs in the lower 70s. South winds 15 to 25 mph with gusts up to 35 mph.
Tuesday Night
Cloudy with a 30 percent chance of showers. Lows in the lower 60s.
Wednesday
Passing clouds with a chance for showers and storms through the afternoon. Highs in the mid 70s. Chance of rain 30 percent.
Wednesday Night
Cloudy with showers and storms possible. Severe weather unlikely, but can’t be ruled out. Lows in the mid 60s.
Thursday
Cloudy with storms, some severe, through the day. Highs in the lower 70s. Chance of rain 80 percent.
Thursday Night
Mostly cloudy with showers and storms possible, mainly before midnight. Lows around 40. Chance of rain 40 percent.
Friday
Mostly sunny. Much cooler with highs in the mid 50s.
Friday Night
Partly cloudy in the evening, then clearing. Cold with lows in the lower 30s.
Saturday
Sunny. Highs in the upper 50s.
