Mesoscale Discussion 0001
NWS Storm Prediction Center Norman OK
0200 AM CST Wed Jan 03 2018
Areas affected...Northern Florida...much of southern Georgia
Concerning...Winter mixed precipitation
Valid 030800Z - 031400Z
SUMMARY...Light freezing rain will develop over southern Georgia and
far northern Florida through morning. A changeover to all snow will
occur from west to east after 12Z over Georgia and by 18Z into
southern South Carolina.
DISCUSSION...Surface analysis currently shows the freezing line
extending from coastal SC and GA across northern FL, where the air
is also dry. Showers were beginning to increase in coverage across
the eastern Gulf of Mexico and over FL, where temperatures were
mainly above freezing. However, cooling of the dry boundary layer
should lead to a drop in temperatures, with an effective southward
trend in the freezing line position.
Meanwhile, temperatures aloft are above freezing over most of the
MCD area, with the warm nose located around 850 mb. This should
result in freezing liquid precipitation, except perhaps on the far
northern and western fringes where mixed precipitation is possible
due to colder boundary layer temperatures.
As the upper trough approaches, temperatures aloft will cool from
west to east, and lift will be enhanced with a notable increase in
frontogenetical forcing after 12Z especially over GA. Through 12Z,
the air mass will continue to gradually moisten with expanding
precipitation and rates of 0.05" to 0.10"/hr likely with freezing
rain over southern GA and far northern FL. Beyond 12Z, precipitation
will transition to snow, perhaps up to 1"/hr into the late morning
across southeastern GA into southern SC.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 29778442 30128449 30418447 30738435 31348377 31538334
31698254 32218110 32118062 31638096 31218128 30238201
29778258 29628300 29688395 29778442