Dense Fog Advisory 23, NWS Atlanta, GA

Area Forecast Discussion
National Weather Service Peachtree City GA
415 AM EST Sun Dec 26 2021

...Morning Area Forecast Discussion...

.SHORT TERM /Today through Monday/...

WAA pattern in place as the mid-level ridge which has dominated the
pattern across the southeast remains anchored over the central and
eastern gulf.  Result is broad WSW flow throughout the column with a
decent moisture around in the low levels.  With a trof in place over
the PAC NW, there wont be much change in the pattern through the
short term. 00Z FFC sounding indicated a fairly stout inversion at
850mb in conjunction with a significant dry layer atop a fairly
moist BL. This should result in some early morning fog this morning
and low level clouds hanging in most of the morning area wide.
Biggest question will be if we can mix them out enough to get some
sunshine by afternoon. Best chances should be in the eastern portion
of the area...but with clouds potentially playing a role in holding
temps down a degree or two from the highs. Regardless...afternoon
highs will be within a few degrees of the daily records as will
overnight lows the next 2 nights.

30

.LONG TERM /Monday Night through Saturday/...

Persistent upper level pattern remains in place, with large ridge
over the eastern Pacific leading to standard negative PNA pattern
across the CONUS, with large trough over the west coast and west
Atlantic based ridging over the southwest. Large ridge in the
Pacific intrudes all the way into the Arctic, allowing for
numerous Arctic- based tropopause polar vorticies to rotate down
into and around the deep west coast trough as shortwaves within it
and eject into the Great Plains. This will create a parade of
surface based cyclones in response to surface baroclinic zone in
the form of a thermal boundary draped across eastern two-thirds of
the CONUS. These all will pass to the north of the CONUS and
never really drive the frontal boundary into the CWA, with mass
response keeping persistent south to southwesterly winds in the
area off the GoM.

So all that is a fancy way of saying that it's gonna be a warm and
wet one for late December this week. Near constant WAA off the GoM
under the south to southwesterly flow means Tds will be in the 60s,
keeping overnight temperatures from falling off below 60s in many
locations, at least until late in the week where a boundary may push
into north GA and provide some small relief there. This means
overnight min temps will be 15-30 degrees F above average in many
places, especially Tuesday and Wednesday night, where we may get
close to tying or even breaking record high minimum temperatures.
Day time temps will be warm, though tampered a bit by cloud cover
and potential rainfall, with highs in the upper 60s to 70s. These
are still well above average (10-20 degrees) and could broach
some record highs depending on just how much sunlight can break
through on a given day.

Showers will be possible across North GA on Monday night into
Tuesday as clouds forming in the low-level WAA may be able to
squeeze out some lighter precipitation. Models are consistent in
showing boundary driven by sfc low moving closer on Wednesday into
Thursday, leading to heavier rain especially across North GA. Some
instability is present with this, and given high Tds, definitely
worth paying attention. Upper-level forcing will be lacking, but
still enough shear is in place that some organization of updrafts
could be possible, and SPC has already denoted a previous area to
watch just to the west of the CWA the previous morning.

After this, some increasing confidence in seeing a bit of a respite
from the rain on Friday as the boundary pushes part of the way into
the area, which will also bring the aforementioned respite in
overnight lows across north GA. This is short lived, as new system
forming to the west quickly pulls the boundary back north.
Definitely some timing and strength differences in this next system
across the guidance, so have chosen to keep PoPs at chance next
Saturday into Sunday. Definitely will want to keep an eye on this
system, as guidance has hinted at a pretty stout front with this
that would have access to better upper level forcing than anything
in the previous week and a very warm, moist airmass.

Lusk

&&

.AVIATION...
06Z Update...
MVFR Cigs should continue to lower across the TAF sites the
remainder of the overnight. Still can't rule out some patchy IFR
cigs around the sunrise hours 10-15z. Model cross sections suggest
a more patchy IFR cig this morning with more widespread IFR
possible Monday AM. Southwest winds expected through the period
albeit light and generally less than 6kts areawide.

//ATL Confidence...06Z Update...
medium confidence on ceilings.
high confidence all other elements.

30

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          75  55  71  58 /   0  10  20  10
Atlanta         72  58  70  60 /   5  10  20  10
Blairsville     68  50  66  54 /   5  10  20  20
Cartersville    73  56  71  58 /   5  10  20  20
Columbus        72  57  74  60 /  10   5  10  10
Gainesville     72  56  69  58 /   0  10  20  20
Macon           75  55  74  59 /   5   5  10  10
Rome            73  57  71  59 /   5  10  20  20
Peachtree City  73  56  71  58 /  10  10  20  10
Vidalia         74  57  75  60 /   0   5  10   5

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SHORT TERM...30
LONG TERM....Lusk
AVIATION...30

Hazardous Weather Outlook
National Weather Service Peachtree City GA
533 AM EST Sun Dec 26 2021

GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086-
089>098-102>113-271045-
Baldwin-Banks-Barrow-Bartow-Bibb-Bleckley-Butts-Carroll-Catoosa-
Chattahoochee-Chattooga-Cherokee-Clarke-Clayton-Cobb-Coweta-
Crawford-Crisp-Dade-Dawson-DeKalb-Dodge-Dooly-Douglas-Emanuel-
Fannin-Fayette-Floyd-Forsyth-Gilmer-Glascock-Gordon-Greene-
Gwinnett-Hall-Hancock-Haralson-Harris-Heard-Henry-Houston-Jackson-
Jasper-Jefferson-Johnson-Jones-Lamar-Laurens-Lumpkin-Macon-
Madison-Marion-Meriwether-Monroe-Montgomery-Morgan-Murray-
Muscogee-Newton-North Fulton-Oconee-Oglethorpe-Paulding-Peach-
Pickens-Pike-Polk-Pulaski-Putnam-Rockdale-Schley-South Fulton-
Spalding-Stewart-Sumter-Talbot-Taliaferro-Taylor-Telfair-Toombs-
Towns-Treutlen-Troup-Twiggs-Union-Upson-Walker-Walton-Warren-
Washington-Webster-Wheeler-White-Whitfield-Wilcox-Wilkes-
Wilkinson-
533 AM EST Sun Dec 26 2021

This Hazardous Weather Outlook is for portions of North and Central Georgia.

.DAY ONE...Today and Tonight...

A Dense Fog Advisory is in effect for Northwestern Georgia until
10 am. Please leave plenty of distance between you and other
drivers as visibility may drop quickly to a quarter mile or less.

.DAYS TWO THROUGH SEVEN...Monday through Saturday...

There is a slight chance of thunderstorms Wednesday across north
Georgia and across both north and central Georgia on Thursday.
Primary threats are heavy rain, strong, gusty winds and
occasional lightning.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed through tonight.