Another round of cold temps. through Fri. night will ease over the weekend with highs 60+ Sat./Sun. but with gusty winds Sat. This relatively long stretch of cold has been helped out by an area of abnormally high sea surface temps. -- see map below -- over the N. Pacific. This warm water is helping to solidity & maintain an upper level ridge over the E/NE Pacific. The stout ridge helps & allows an upper level trough to dominate the Central & Eastern U.S. -- "downstream" from the upper level ridge (that's mother nature's way of trying to maintain atmospheric balance). This persistent trough over the Central U.S. has acted like a funnel for cold air in Canada to drive southward with occasional extreme instances of cold as the polar vortex shifts south & west within the more broad upper level trough.
By Monday, an upper level disturbance & surface moisture will move from the Gulf of Mexico northeastward across the First Coast. Showers will develop by Mon. & continue into Tue. At the same time, another surge of arctic air will be spreading south as the upper level trough reloads & retrogades slightly. It's still a little early to know exactly how this pattern will evolve, but there's potential for some significant rain for Jacksonville & surrounding areas with snow not all that far to the north before temps. dip to -- & below -- freezing again Wed.-Thu.
A beautiful sunrise early Thu. (so-called mackerel sky). Photos below are from Mike Baker.... Lisa Waud... Harry Solsor... & my wife(!):