The primary weather concern during this period should occur between
Wednesday and Thursday as a
deepening trough over the Great Lakes
phases with a
shortwave tracking along the Gulf Coast. Due to the
nature of this setup (two systems merging with model discrepancies
regarding the timing and speed of both) uncertainty in the forecast
outcome for Georgia increases rapidly after Wednesday. With this
being said, the potential exists for wintry precipitation in north
Georgia if the sizable
pool of cold air in the Plains (
progged in
the
ensembles) can reach Georgia in time phase with
moisture moving
north from the Gulf. Another potential outcome would be for
moisture
and associated precipitation to move out of Georgia before the
coldest air arrives. This scenario would
likely lead to just a few
snow flurries in the mountains. We`ll see how things come together
over the next few days. For right now there has been enough
consistency over the last 6 to 10 runs of the GEFS and EPS to say
that precipitation is
likely (>60% chance) between Wednesday and
Thursday. Meanwhile there are enough GEFS and EPS members to warrant
a 20 to 30% chance for impactful wintry weather in the north Georgia
mountains, and a 10 to 20% chance of impactful wintry weather along
and north of Interstate 20. For a graphical depiction of the threat
please see the Probabilistic Winter Storm Severity Index
(wpc.
ncep.
noaa.gov/wwd/wssi/prob_wssi.php).
The other noteworthy aspect of the weather next week should be the
return to below average temperatures. The greatest departures from
average are favored between Wednesday and Friday, and their
magnitude will depend on how strong the push of cold air from the
Plains is. Current GEFS and EPS guidance is maintaining a 7 to 10
degree spread between the 25th and 75th percentile in the
temperature forecast. This suggests lower confidence the exact
forecast temperatures, despite high confidence in the occurrence of
below average temperatures.
