The Ruskin NWS explains it all, the upper level winds are going to be extremely strong and this brings about the possibility of at least a few isolated severe storms.

Although I am much better at reading tropical features than US wx features, I have a few feelings about this event:
1. The western portion of Central Florida seems to have the best shot at isolated tornadic activity with this event. The storms, while they should be weakening, will be very intense with this squall line. F0 or F1 tornadoes can't be ruled out over the western part of C. Florida.
2. Eastern C. Florida has a lesser threat of tornado touchdowns, but we have a very great threat of downburst winds as the thunderstorms weaken some. As thunderstorms weaken, they typically do so by "exhailing". These are known as downburst winds, although even slight signs of rotation can make them weak F0 tornadoes. Downburst winds can be as weak as 40-50 MPh and as storms as 100 MPh.

Hail, excessive lighting, and strong winds are a threat with any strong or severe thunderstorms. Although torential rain is always possible, my experiences with squall lines (97/98 El Nino, whew!) generally included a lot of large hail. This may be true this time as well because of cool slots of air in the middle levels of the atmosphere.

With this being said, I'd suggest that all residents pay close attention to a *REALIABLE* source of weather information. A NOAA weather radio with fresh batteries is always a good idea as this worst of this squall line may roar through overnight. I should also mention that squall lines that come through at night also tend to be on the more severe side. I am not sure of a reason for this, but many personal wx experiences have brought this. A severe weather plan is also a good idea just in case a warning is issued for your area.

Welcome to the El Nino winter, folks.