Air Resources Laboratory banner image
Air Resources Laboratory web site National Oceanic and Atmospheric Administration (NOAA)

ga discuss

Office: FFC

FXUS62 KFFC 181725

Area Forecast Discussion
National Weather Service Peachtree City GA
1225 PM EST Mon Dec 18 2017

Updated for the 18Z Aviation Discussion.


.PREV DISCUSSION... /issued 334 AM EST Mon Dec 18 2017/

.Dense Fog Advisory Through 9am...

SHORT TERM /Today through Tuesday/...

Ample moisture along with stalled front to the south has resulted
in dense fog formation across portions of the area. Quarter mile
visibility may not technically be widespread as of yet but given
increased travel concerns for this week, have pulled the trigger
on an advisory. Although the radar continues to be rather benign,
still some drizzle for most areas and will carry in initialized
grid set this morning.

Models appear to be a bit overdone thus far with the precip axis
to the south and mid level energy really isn't all that strong
over Central GA for what the short term models are trying to
project rain wise. Still think there will be an uptick though in
precip this afternoon given abundant moisture and precipitable
water in excess of 1.75 inches. Will carry mid range chance
transitioning to small area of likely but no thunder inclusion at
this time.

Overall, rain chances will be on the decline through Monday night
as deep layer moisture decreases initially. Visibility
restrictions look to be limited to the extreme southern portions
of the area this go around. Next shortwave will approach late
Monday night however with likely pops entering NW zones once again
by the tail end of the short term period.


LONG TERM /Tuesday Night through Sunday/...

Unsettled weather is still expected for much of the long term

There is continued potential for heavy rainfall with a risk for
Flash Flooding across far n GA, from RMG to N GVL, Tuesday night
into Wednesday. Potential rainfall is running in the 1 to 3 inch
range with much of this rainfall coming late Tuesday night and
early Wednesday. This all due to deep moisture in the WSW flow aloft
interacting with surface low pressure and a slow moving warm front
moving over the area. Rainfall is expected to diminish/end late
Wednesday and Wednesday night.

Another cold front will approach the area Friday and potentially
stall across the area Saturday into Sunday. The GFS and European
are significantly different with the GFS faster than the European
with the front, moisture and rain chances and how far the front
gets into the area. The European moves the front north as a warm
front Saturday night and Sunday while the GFS keeps the front
S of the area. These differences make the forecast low confidence.

Temperatures are expected to be above normal through the period.



18Z Update...
A mix of IFR/MVFR/VFR should become mostly VFR this afternoon
however cant dismiss patchy MVFR cigs. Cigs will once again become
IFR tonight as patchy fog develops across the forecast area. Areas
across central GA will see LIFR conditions however there is an
outside chance ATL/AHN could also see LIFR conditions late
tonight. Winds will be light west to calm through the forecast.
Scattered showers will move across much of the forecast area this
afternoon, exiting tonight.

//ATL Confidence...18Z Update...
Medium on cigs and timing of precipitation.
High on remaining elements.



Athens          59  45  67  55 /  30  20  50  70
Atlanta         58  48  64  57 /  30  20  40  70
Blairsville     59  38  63  51 /  10   5  80  90
Cartersville    57  44  61  54 /  20   5  70  80
Columbus        63  54  68  60 /  60  30  10  60
Gainesville     59  46  63  55 /  20  10  70  80
Macon           67  51  69  57 /  60  40  10  60
Rome            58  42  60  53 /  20   5  80  90
Peachtree City  59  47  65  56 /  40  20  30  70
Vidalia         71  57  73  59 /  60  50  10  30