Winter Storm - January 3, 2018

In the early morning hours, light precipitation spread across northeastern Florida and southeastern Georgia. Precipitation began as wet snow mixed with sleet over inland southeastern Georgia and freezing rain mixed with sleet over the Suwannee Valley. Surface temperatures Wednesday morning were at or below freezing along the I-10 corridor just west of the Jacksonville metropolitan area, along/west of the I-75 corridor in north central Florida and across all of southeastern Georgia (Figure 3). Above the freezing surface layer was an above-freezing melting layer which was deep and warm enough to melt the snow that fell through the layer as shown in the 12 UTC (7 AM EST) upper-air soundings from Tallahassee and Jacksonville. In Tallahassee, the shallower melting layer melted the snow, however, the layer between the cloud bases and the surface was below freezing causing freezing rain and even some liquid droplets to re-freeze into ice pellets (sleet) before reaching the surface. To the northeast of Tallahassee, the melting layer becomes smaller resulting in mainly snow.  To the south and east of Tallahassee, the melting layer becomes deeper and warmer resulting in mainly freezing rain where the liquid water droplets freeze upon contact with the surface. Near Jacksonville, along the Florida Atlantic coast and central Florida, the melting layer is deep and warm enough to melt all the snow particles resulting in cold rain. Later in the morning, as the upper trough pushed past the region, colder air began to advect in due to the upper level winds shifting from southwesterly to northwesterly. With colder air overtaking the low level melting layer, the precipitation type became mainly snow across southeastern Georgia allowing for some heavier snow bands to develop. Precipitation continued to move northeastward until ending in the afternoon hours (Figure 4).