I jumped in to make some tweaks to the going forecast and ensure our messaging is positioned well this weekend. I have a growing concern that the next few days (or week) will be more than just a sensible inconvenience. There is a low, albeit in my opinion growing, possibility for flooding near the Nature Coast and parts of North-Central by early next week.
I find it ironic that this time last year we were in the midst of an extremely wet pattern that eventually yielded the hashtag #Rainesville and flooded many out of their homes in Dixie County (8/2/15). The synoptic pattern that most reliable model guidance is leaning toward over the coming days is one strikingly similar to last year’s setup, which included the presence of a weak surface low in FL panhandle along a stalled front and weak trough aloft. Certainly, there are some small differences and this could result in a much different result, geographically speaking. I distinctly remembering, however, that only the RPM (or WRF) model was anywhere close to the eventual 10 inches of rain that fell near Steinhatchee in one night.
In this regime, tropical moisture is funneled through the Gulf and across the northern third of the state. The incredibly warm water temperatures may work in tandem with the vorticity and lift from the nearby surface low to produce clusters of convection in the overnight hours that pound the coastal communities through daybreak. This instability is then transferred inland, enhancing diurnal convection further east (although not with the same intensity or coverage). GFS, Euro and CMC modeling all paint a picture of 5″+ of rain in the next 120 hours immediately along the coast, but vary greatly in how much of that will be able to spread inland.
I adjusted pops to reflect higher confidence in the rainy pattern, noting Sunday and Monday with the highest chances when guidance suggests the surface low will be closest to NFla. By Tuesday and Wednesday, there is general model agreement that the weak low will retrograde to the northwest and be absorbed by the next strong shortwave diving down into the Midwest. I tailored temps to rain chances and considered the timing of the rain as well. The flow off the Gulf will be strongest Fri-Sun, sending clouds/rain in sooner thus mid 80’s. By Tue/Wed, a more typical sea breeze pattern will resume with opportunities for warmer temps. We could be looking at some sea breeze collision days next week as the weak wind pattern returns and moisture stays high.