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Area forecast discussion...updated
National Weather Service Peachtree City Georgia
930 PM EDT Mon Oct 21 2019

Update...
thunderstorm chances have been reduced to slight chance
with the pops for showers left as they were as the cold front
is still approaching the area. The airmass on the whole is not
very unstable and the risk for severe storms is diminishing.

&&

Previous discussion... /issued 703 PM EDT Mon Oct 21 2019/

Short term /tonight through Tuesday night/...

To begin the short-term period, north and central Georgia remain
under a southwesterly flow pattern aloft, with an upper level
longwave trough approaching the area from the west. At the surface,
a low pressure system will continue to move northeastward from the
northern High Plains towards the Great Lakes region. A southwest to
northeast oriented cold front extends from this system into the
southeastern Continental U.S. And is currently located near the border of
Mississippi and Alabama, continuing its eastward move towards the
forecast area. High temperatures across the area this afternoon will
reach into the 70s across north Georgia and into the low to mid 80s
across central Georgia.

Chances for showers and thunderstorms will increase during the mid-
afternoon over northwest Georgia and progressively increase
southeastward across the area during the overnight period as the
front moves into the forecast area. While instability associated
with this system is anticipated to be fairly limited, 0-1 km low-
level shear will be enhanced to 20-30 kts ahead of the front and 0-6
km bulk shear values could approach 60 kts. This indicates the
likelihood of an organized line of thunderstorms ahead of the cold
front, with stronger storms embedded within the line capable of
producing strong to damaging wind gusts. There is also a slight, but
non-zero chance for a brief spin-up tornado embedded within the
line, as well.

Gulf moisture spreading over the area this morning and early
afternoon has allowed dewpoints to climb into the mid 60s and will
continually increase precipitable water values to about 2 inches
ahead of the front. Rainfall totals are trending lighter than the
previous forecast and are not anticipated to be overly impressive,
ranging from about a quarter of an inch in central Georgia and an
inch in northwest Georgia. Regardless, it is possible that some
stronger storms within the line could produce locally heavy
rainfall, particularly across far north Georgia where precipitation
chances are expected to be highest.

The cold front will then clear the area during the day on Tuesday,
with the the front and associated precipitation clearing completely
by late Tuesday afternoon. Slightly elevated northwesterly winds and
cooler and drier air can be expected in the areas behind the front
throughout the day on Tuesday, with high temperatures in the 60s in
north Georgia and in the 70s in central Georgia and overnight low
temperatures dropping into the 40s across the area.

King

Long term /Wednesday through Monday/...

No major changes made to the extended forecast. Things begin with
high pressure working into the southeastern U.S. With a cold northwest
drainage flow. This will allow for temps to fall into the upper 30s
for the NE mountains and lower 40s elsewhere across north Georgia. There
will be 5 to 7 degrees of dewpoint depression but could still see
some patchy frost given light winds.

The high will remain the dominant feature through Thu afternoon
although airmass will modify slightly from upper 60s on Wed to
around 70 for Thu afternoon.

After this, it will be a squeeze play for the local area as
northern stream upper level energy slides into the Central Plains
while Gulf energy moves in from the SW. This will allow for a
combination of upper energy forcing and isentropic forcing to
produce likely pops. Should these trends continue with subsequent
forecasts, these pops will need to be increased to categorical.
Looks like the higher pops will stick around for awhile with no
quick frontal progression. Significant clearing not anticipated
until the very end of the extended period when high bridges over
the area for Sunday.

Deese/01

Aviation...
00z update...
increasing potential for showers and some thunderstorms along
with MVFR-IFR ceilings and some MVFR vsbys.
Clouds and ceilings will clear on Tuesday.
Surface winds south-southeast less than 10 kts becoming SW then west-northwest
late tonight and Tuesday, increasing to 10-15 kts with
some gusts 20-25 kts.

//Atl confidence...00z update...
high confidence for winds to start then medium confidence
after 06z.
Low to medium confidence for all other elements.

Bdl

&&

Preliminary point temps/pops...
Athens 65 74 45 70 / 70 50 0 0
Atlanta 60 70 46 67 / 70 30 0 0
Blairsville 54 65 39 62 / 80 40 0 0
Cartersville 56 70 42 68 / 80 10 0 0
Columbus 63 74 48 72 / 70 20 0 0
Gainesville 60 70 45 67 / 80 40 0 0
Macon 67 76 46 72 / 60 50 0 0
Rome 56 70 42 69 / 80 10 0 0
Peachtree City 60 72 44 69 / 70 30 0 0
Vidalia 70 80 50 73 / 40 40 5 0

&&

Ffc watches/warnings/advisories...
none.
&&

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