Rain chances isolated locally. Tropics starting to wake up?
Another mostly cloudy day across the Tennessee Valley on this Tuesday. The frontal boundary that was draped across our region yesterday has sunk southward into central Alabama and Mississippi, and with it, the primary focus for afternoon shower and storm development. However, there are a few spotty heavy downpours on radar from north Mississippi over into northwest Alabama. Temperatures are a good 8 to 10 degrees below average again because of the cloud cover, generally in the lower 80s... although we have a few spots hanging in the upper 70s from Iuka, MS to Russellville, AL.
The chance for a few very isolated and spotty showers and storms will continue through the afternoon and into the early evening before we lose daytime heating. The main potential for these is over north Alabama / Mississippi, but I can't completely guarantee that there won't be one or two over southern middle Tennessee. Most of us areawide, however, will likely be dry today. Those showers fade away overnight and then we drop back toward the mid to upper 60s for morning lows under mostly cloudy skies.
Rain chances for the rest of the week and into the weekend will stay very isolated, with the frontal boundary focusing showers and storms well south of our area. Isolated activity is possible each afternoon and early evening though. Otherwise, expect partly sunny skies with afternoon highs in the mid to upper 80s through the rest of the week, and likely sliding into the lower 90s by the weekend with a bit more sun, especially on Saturday. Morning lows will generally be in the mid to upper 60s each day.
We are going to have to start watching the tropics vigilantly as we move forward. Background conditions still aren't overly favorable just yet, but there are forcing mechanisms that are trending in a direction more favorable for systems to develop the next couple of weeks. A lead wave that moved off the African coast has diminished and lost its potential to develop. However, the National Hurricane Center is flagging two other disturbances, one near the Cabo Verde (formerly the Cape Verde) Islands and another out in the open Atlantic that will approach the Caribbean over the next few days. Both of them have a 20% chance of developing into a tropical depression or stronger over the next 5 days.
You will see individual model runs do some pretty wild things over the next several days. The 12z run of the GFS model has done such a thing. Don't pay attention to the noise. This is why models are only tools and not the actual forecast. It's the same principle as you would not put your books on the screwdriver you used to put your bookshelf together. You put your books on the finished bookshelf, the final product.
We can get an overall idea of a consensus across models by using ensembles. These systems take a particular model run, tweak conditions a little for each ensemble member, and then make a model run off each member... and then we compare, contrast, and take the average of all those ensemble members together. The Euro ensembles currently do show support for a developing tropical system in the Caribbean over the next 5 to 7 days. However, the latest runs of that keep it weak and on a westerly track. It should be noticed that the GFS ensembles, the ensemble set run from the model that showed a scary Gulf hurricane on today's run, don't show the system developing into anything major. When the ensembles don't even agree slightly with their main model they're associated with, that's usually a big red flag to take the main operational model there with a grain (if not a full shaker) of salt.
The bottom line is that the tropics are trying to wake up, and there are a couple of systems we need to watch, but nothing is imminent or particularly threatening yet. Don't let social media alarmists and click-bait sites tell you otherwise, just because an individual model shows something scary. Those people do that for likes, shares, and ad revenue. Could something significant end up actually developing? Sure! We just have zero way of knowing yet. Period. No matter what you may hear otherwise from those pages and sites. Sort through the noise and stick with proven and trusted sources. We will raise the red flag and get your attention if something looks significant or threatening.