Windy Labor Day & Problems From Lee?

Hey there...hope you are enjoying your Labor Day weekend!  What a big change over the past 24 hours!  After nearly reaching 100 degrees yesterday, we held steady in the 70's today, with plenty of clouds and scattered showers associated with moisture from Lee and the cold front that moved across the area.  Tonight, a look at the surface map shows the front pretty much through the entire region, and the cooler, drier air moving in from the north.

With high pressure behind the front, and lower pressure at the center of Lee, our region will be stuck in a pretty big pressure gradient tomorrow, leading to a breezy Labor Day.  A Lake Wind Advisory is in effect for Monday, with NNE winds of 10-20 mph, gusting as high as 30-35 mph, with the strongest gusts the farther south you go.  And a big question mark for tomorrow will be how quickly we clear out. With moisture streaming north from Lee, it may take most of the day for clouds to clear out east of the Mississippi River.

Looking ahead, since the last post there have been some changes in the forecast models' idea of how the remnants of Lee will impact our weather picture this week.  It's a rather complicated situation with multiple variables, so some tweaking may occur to the forecast over the next few days.  As Lee begins to wind down and become post-tropical, it will be phased into the existing cold front that is moving through our area, and will move northeast along that front.

At the same time, Hurricane Katia is still slowly churning northeast across the Atlantic, headed in the direction of the east coast.  As you can see below, it still appears that Katia will not make landfall, but will get a little too close for comfort.

 

Ultimately, by mid-week it looks like the remnants of Lee will develop into what we call a cut-off low...an area of low pressure that is not connected, or "cut off", from the steering currents of the jet stream.  These features typically hang around for a few days, and lead to cloudy, cool, and sometimes rainy weather.  And with Katia approaching from the east, this system will effectively block other features, such as this low, from moving east, at least until Katia exits the picture. Here's what that looks like on the model chart by Wednesday morning:

Notice the "L" surrounded by circles over MS & AL?  That's our cut-off low.  Here's the surface chart for the same time period:

Notice the purple over the Local 6 area?  That indicates light rainfall over our region.  All of this is has been hinted at by one or two of the models for a few days, but today just about all of the models came into agreement on this scenario, which led to some big changes to the forecast for this week.  I went ahead and kept things mostly cloudy for Wed.-Sat., with daily 30-40% chances for rain, and slightly cooler temperatures.  We'll see how this whole thing plays out.....if Katia's track diverges, then the forecast will have to be adjusted as well.  Stay tuned.