TONIGHT: NAM is consistent with bringing this vorticity center shown into coastal Central Florida with the surface reflection of a weak low level circulation over South Florida, The entire trough moves WNW over night with greater moisture continuing from what is currently in place on Sunday behind it being dragged behind on its tail flank. It is noted that temperatures aloft are much warmer now, or are forecast to warm, thus thunder might be hard to come by heading into Sunday. It could well be that any rain showers with cool winds will stabilize large areas right from the get go, and with such slow movement of shower activity it might be that widespread coverage at one time will be hard to come by if ever. This is more of a 'different slant of the story' from the main broadcast weather headlines possibly been heard elsewhere.
Meanwhile, Storm Ernesto is moving West into the Caribbean as we read and speak. The official guidance can be seen on the future track on any channel. Interestingly, the GFS shows the track to move a little toward the south, and the latest guidance on CIMMS shows the Deep Layer Mean flow for this 'less than well organized system' could take it in a more WSW direction for quite some time by later today and into tonight, into Southern regions of the Yucatan or a bit further north. Based on those tid bits of (model data) information as well as the Euro which last I looked took it practically into Central America the concerns for other than Jamaica are as of right now not too high, at least not in regard to Florida's perspective.
Locally, rain chances look questionable to me through Monday, with both locations and timing of rainfall a tough call. With warm air aloft, any rain cooled air regions will have a tough time manifesting much of anything more due to limited instability as cloud cover increases. We'll just have to see how it all plays out. Could end up being a mainly nocturnal event from start to finish near the east coast and eventually a broader area heading into Monday.