The above image is the latest Day 7 Severe Weather Outlook from the Storm Prediction Center. Usually, we do not get any heads-up from the SPC on a severe threat because many of the systems that move through during this time of the year do not look all that impressive because of weaker instability or cooler temperatures. They usually like to wait until the higher-resolution models come into focus before making an outlook that would include the threat of severe storms.
Every once in a while, the ingredients will show up on the long-range global models and they will put out a generalized severe outlook graphic like the one above. It looks like Saturday is already showing up as having the potential for severe storms.
This is the latest projected sounding from the 00z run of the European model valid Saturday evening at 6:00 pm for just north of the city of Birmingham. As you can see, the glaring item that catches your attention is the box on the far right side towards the bottom that says Psbl Haz Type, which is the Possible Hazard Type. In that box, it has TOR for tornadoes listed.
This sounding is also showing forecast instability values over 1700 J/kg, which is rather high for this time of the year. Helicity values at both levels are high enough to support rotating cells. Shear is actually a little lower than we usually see for this time of the year, but still sufficient enough to support severe storms.
At this point, this would be called a Slight Risk for severe storms, but we’ll have to watch to see if this will be upgraded as we get closer to the event. At this point, highs will be in the upper 60s to the mid-70s across the area on Saturday with dewpoints in the mid to upper 60s. We’ll have plenty of moisture with those warmer temperatures, and mixed that in with the instability and other factors I mentioned earlier, I would say we will need to pay attention to the forecast throughout the week.
Central Alabama Weather 