WED. MORNING UPDATE:
Things progressing as expected so far with just wet roads across Jax & the First Coast even as some sleet & snow mixes with the rain across SE Ga. That's it for today: wet, cold though most of the rain will be light or just a drizzle. This has been a major winter storm for areas farther west & north with parts of I-10 closed early Wed. west of Tallahassee due to ice.
The next "item of interest" is tonight as a secondary disturbance moves across the First Coast. More rain will develop with an additional tenth to third of an inch. The "pickle" is that temps. will drop to near freezing. While a bit of light sleet or a flurry could mix with the rain, the chief concern is if temps. hit freezing & icy patches develop on the roads. The greatest risk would be on bridges & overpasses between 2am & 8am. This will essentially be an hour by hour forecast, but it is a legitimate concern late tonight/early Thu. The satellite imagery below shows the 2nd disturbance -- the enhanced cloud cover over the Northern Gulf of Mexico & stretching out across the Gulf Coast.
From our Jax N.W.S.:
ORIGINAL TUE. NIGHT POST:
The winter storm is panning out pretty much as expected with heavy ice & snow north of the First Coast & a good soaking rain for Jax, NE Fl. & SE Ga. Some of the rain should still manage to mix with some freezing rain/sleet/flurries over SE Ga. but with little if any accumulation. With temps. near 32 degrees, patchy ice could form early Wed.-- especially on bridges & overpasses. For Jax & NE Fl., it's plain old rain. There's a very outside chance that a bit of sleet & or a flurry could mix with the rain Wed. afternoon & evening but no accumulation. We'll once again have to beware of possible icy bridges/overpases early Thu. as temps. dip to near freezing though I suspect most of the wet roads will be drying out before ice can form -- something to watch for though including in the Jax metro area.
Click ** here ** to see a slideshow of snowfall across the southland, especially Georgia.
Pink shading is winter storm WARNING... :
There was an interesting phenomenon on First Alert Doppler HD Tue. evening -"bright banding" (see the image below). Bright banding occurs on radar when the radar beam hits water (higher reflectivity than ice) that has melted around a falling snow flake. This band often correlates with mixed precip. as was the case late Tue. Then the area to the north & west of the bright band is all snow.
The illustrations below show the temp. profile for freezing rain vs. sleet vs. snow. Freezing rain is rain that falls through a warm layer throughout most of the lower atmosphere but freezes upon impact when surface temps. are at or below 32 degrees.
Sleet occurs when snowflakes melt through a warm layer in the upper atmosphere then refreeze before hitting the ground as small white "balls", often bouncing on the pavement. Sleet can also form when rain drops freeze into pellets before hitting the ground.
Snow occurs when there is no warm layer and flakes remain frozen through the atmosphere all the way to the surface.
From "Earth Gauge":
The good news is that temps. will be much warmer by the weekend!