Flash Flood Warning 1, NWS Atlanta, GA

Area Forecast Discussion
National Weather Service Peachtree City GA
647 AM EST Tue Jan 9 2024

...New 12Z Aviation Discussion...

.SHORT TERM...
(Today through Wednesday)
Issued at 445 AM EST Tue Jan 9 2024

The main focus today will be on active weather associated with a
deep closed 500 mb low currently moving into the Ozarks. As this low
continues to move east-northeast, it is becoming negatively tilted
as a shortwave rotates around its southern extent, allowing it to
rapidly intensify. An occluded front is extending from the
associated surface low into the Lower Mississippi River Valley. At
the end of this occluded front is a triple point, from which a warm
front extends to the southeast into western Alabama and central
Georgia, and a cold front extends south to near the MS/AL state
line. Meanwhile, A strong surface high is positioned to the
northeast of the forecast area, just off the New England coast, with
a CAD wedge in place along the lee side of the Appalachians and
north Georgia.

As the low pressure system continues to lift to the northeast, the
warm front continues to advance northward through the forecast area.
Strong warm air advection driven by a powerful 80+ kt low-level jet
is overspreading the forecast area, which will bringing copious
moisture into the area, particularly in central Georgia, where
dewpoints will surge into the upper 50s to low 60s in central
Georgia by mid-morning. Widespread isentropic showers are also
ongoing in north Georgia to the north of the warm front.
Temperatures in the highest elevations in far northeast Georgia (and
within the wedge) may remain cool enough for a light rain/freezing
rain mix to be observed at elevations above 2500 ft over the next
couple of hours. However, with strong warm air advection and latent
heating processes already ongoing, additional ice accumulations will
be minimal and the chance for freezing rain should come to an end
entirely by sunrise.

The cold front will advance closer to the forecast area early this
morning, at which point things could get quite interesting with a
line of heavy showers and potentially strong thunderstorms moving
from west to east across the forecast area this morning and
afternoon. With the warm sector continuing to expand northward,
there should be enough instability in central Georgia and portions
of north Georgia to support surface based storms this morning into
the afternoon. Severe weather, heavy rain, and strong gradient winds
will all be possible in association with this system, which will be
discussed below:

1 - Severe Weather: A strong line of thunderstorms ahead of the cold
front will enter west Georgia this morning, advancing eastward
through the forecast area this morning and afternoon. The severe
weather potential will similarly spread from west to east with the
line of storms. As warm air advection continues to spread into
Georgia, the boundary of the wedge should retreat northward over the
next few hours. Warm fronts do not always fare well against the
wedge, but in this case, with such a strong low-level jet at 850 mb
overspreading the region, there is a greater likelihood than normal
in mixing out the wedge. This is important because it will dictate
how far north the warm sector is able to ultimately advance, and the
severe weather potential will be impacted by how much instability
will be present in the warm sector ahead of the advancing cold
front. As the jet sets up and warm front advances further north,
portions of east Georgia will have more time for the airmass to
destabilize. This is well-reflected in the SPC outlook, which
indicates the highest risk for severe weather today will be located
roughly  along and south of a line from Columbus to Macon to
Warrenton where destabilization and the ability to maintain
surface- based storms appears to be most likely. All that said, it
will not take much instability to see severe weather threats in
this low CAPE/high shear environment. The kinematics of this
system will be be quite robust with ample low-level and deep layer
shear, EBWD from 30-40+kt, and 0-1 km SRH from 200-400 m2/s2).
Severe thunderstorms that develop will be capable of producing
strong, damaging wind gusts, especially given the likelihood of
mixing down strong winds aloft. Given the very strong shear and
SRH values, a few QLCS tornadoes will also be possible within the
line, especially where storms are able to interact with the wedge
front and obtain rotating meso-vortices.

2 - Heavy Rain/Flooding: Precipitable water values are continuing to
increase this morning, and are expected to range from 1.5-1.7 inches
roughly along and south of I-20. These values, for context, are near
daily records for this time of the year. As such, the main line of
storms will have plenty of moisture to work with and be capable of
producing bursts of heavy rain as it moves through the forecast
area. A Flood Watch remains in effect in the areas north of the Fall
Line. Additional rainfall amounts of 2-3 inches are forecast with
the remaining isentropic showers and with the line of storms.
Furthermore, orographic enhancement on windward slopes could lead to
locally higher amounts in the mountains of far northeast Georgia,
where up to 4 additional inches will be possible. With efficient
rainfall rates, localized flash flooding will be possible,
especially in urban and low-lying areas. Moreover, numerous creeks
and streams across the area are forecast to reach minor flood stage,
with some potentially approaching moderate stage.

3 - High Winds: A very tight pressure gradient is present due to the
aforementioned surface high to the northeast and approaching low
pressure system. This will keep surface winds strong and boundary
layer well mixed. Sustained winds of 20-30 mph with gusts up to 40
mph will be likely through much of the day. The strong low level jet
at 850 mb early this morning will promote additional mixing of wind
gusts down to the surface, especially in higher elevations, where
wind gusts up to 50 mph will be possible this morning. Considering
heavy rainfall and thus wet soils in association with this system,
strong winds could bring down trees, which would lead to localized
power outages. As a result, a High Wind Warning is in effect for
Murray, Gilmer, Fannin, Union, Towns, White, Lumpkin, and Dawson
counties. Elsewhere in the forecast area, a Wind Advisory remains in
effect. Winds will begin to drop below advisory criteria by 7 PM
this evening in north and west Georgia, and by 1 AM on Wednesday in
central and east Georgia.

On the backside of the system tonight into early Tuesday morning,
there will be enough moisture in combination with near freezing
temperatures to see some scattered light snow showers across far
north Georgia and the western facing mountain slopes. Light snowfall
accumulations of about one-half inch will be possible, but no
impacts are expected. These snow showers are expected to diminish by
sunrise on Wednesday. Lingering mid-level moisture on the back side
of the system will keep skies mostly cloudy across the majority of
north Georgia and portions of central Georgia on Wednesday morning
and early afternoon. However, weather conditions will remain benign
during the daytime on Wednesday with no precipitation expected at
this time. Afternoon high temperatures will run about 3-5 degrees
below climatological normals, in the mid to upper 40s in north
Georgia and in the low to mid 50s in central Georgia.

King

&&

.LONG TERM...
(Wednesday night through Monday)
Issued at 445 AM EST Tue Jan 9 2024

Key Messages:

 - Another storm system will bring showers and thunderstorms to the
   area late Thursday night and Friday. Some thunderstorms may be
   strong.

Colder and drier air will continue to filter into the area Wednesday
night on the heels of the departing cold front and upper trough.
Most locations will drop to near or just below freezing Wednesday
night, with mid 20s across portions of the NE mountains. Warmer
temperatures are forecast for Thursday, with most locations reaching
into the mid to upper 50s and even some lower 60s across the S.

Another storm system will approach the area Thursday night, bringing
a chance of showers and thunderstorms. This system will lift NE on
Friday as a negatively tilted trough, reaching the Great Lakes by
Friday night. A 996 mb surface low is progged to be near Little Rock
by Friday morning. A large area of isentropic lift is forecast to
precede the low, with increasing MUCAPE and wind shear across most
of the forecast area. There will be another threat of severe weather
with this system during the day Friday, and the threat area looks to
be farther to the N than with today's system. GFS MUCAPE values are
forecast to reach near 1000 J/kg as effective shear increases to
over 40 knots in the Atlanta metro area. This will coincide maximum
daytime heating in the early afternoon, with surface temperatures
reaching over 60 degrees and dew points reaching the lower to mid
50s. The wedge/CAD is forecast to hang into NE GA during this time
period, but present indications are that it will be NE of the
Atlanta metro area. Storm total rainfall amounts with this system are
forecast to range from around a quarter inch S of Columbus to close
to an inch across N GA. Residents should continue to monitor the
latest forecast regarding this storm system.

A bit of snow will linger over the N mountains Friday night, but dry
weather is forecast to return on Saturday. Temperatures will be
rather cold over the weekend, with the potential of even colder
weather early next week. A weak southern stream storm system may
move along the Gulf Coast on Monday, bringing light rain amounts and
the chance for frozen precipitation across N GA. NBM low
temperatures Tuesday morning appeared to be too cold. Even though
this was at the tail end of the forecast period, opted to blend 2
parts operational NBM with 1 part NBM 90th percentile to bump low
temperatures up closer to MEX MOS guidance. /SEC

SEC

&&

.AVIATION...
(12Z TAFS)
Issued at 637 AM EST Tue Jan 9 2024

Precipitation continues to overspread north and central Georgia,
including all TAF sites, as the morning begins. Ceilings are
currently IFR across the majority of the forecast area.
Thunderstorms are also expected as the cold front advances through
the area. A TEMPO for TSRA is being carried from 12-15Z at the ATL
metro sites and CSG, and 13-17Z at AHN/MCN. Winds ahead of the
cold front will be E/SE 17-22 kts with gusts as high as 35 kts.
Winds will shift to SW after the cold front passes, after 15Z at
ATL, but winds behind the front will remain nearly as strong. Rain
chances will begin to diminish behind the front, with precip
coming to an end by 18-19Z at ATL. Ceilings will be slow to
improve today, only reaching MVFR around 19Z. Ceilings could
briefly improve to low VFR in the late afternoon, but will lower
back to MVFR after 00Z.

//ATL Confidence...12Z Update...
Medium to high confidence on all elements.

King

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          33  48  31  57 /  10   0   0   0
Atlanta         33  47  34  57 /  10   0   0   0
Blairsville     28  41  26  52 /  40   0   0   0
Cartersville    32  47  29  57 /  10   0   0   0
Columbus        35  51  33  60 /   0   0   0   0
Gainesville     32  44  32  54 /  20   0   0   0
Macon           35  52  31  60 /  10   0   0   0
Rome            33  48  31  57 /  20   0   0   0
Peachtree City  32  49  31  58 /  10   0   0   0
Vidalia         37  53  36  60 /  20   0   0   0

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
Flood Watch through this evening for GAZ001>009-011>016-019>025-
027-030>038-041>050-052>060-066>071-078-079.

Wind Advisory until 7 PM EST this evening for GAZ001>004-011>013-
019>023-030>034-041>045-052>055-066-067-078-079-089>091-102-103.

High Wind Warning until 1 PM EST this afternoon for GAZ005>009-
014>016.

Wind Advisory until 1 AM EST Wednesday for GAZ024-025-027-
035>039-046>051-056>062-068>076-080>086-092>098-104>113.

&&

SHORT TERM...King
LONG TERM....SEC
AVIATION...King

Hazardous Weather Outlook
National Weather Service Peachtree City GA
714 AM EST Tue Jan 9 2024

GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086-
089>098-102>113-101215-
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-
714 AM EST Tue Jan 9 2024

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

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

A Tornado Watch has been issued for portions of central Georgia
until 2 PM.

A High Wind Warning is in effect for portions of Northeast Georgia
until 1 PM today for wind gusts over 50 mph. A Wind Advisory is in
effect for all other portions of the county warning area for wind
gusts to 45 mph. A Flood Watch is in effect through this evening for
areas north of the fall line due to storm total rainfall amounts of
2 to 4 inches. Locally higher amounts are possible, particularly
across the northeast mountains. Scattered thunderstorms are expected
across central Georgia, with severe storms and isolated tornadoes
possible mostly south of a Columbus to Macon line. Isolated
thunderstorms are possible elsewhere.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday...

Another storm system is expected to bring thunderstorms to the
region again Friday. Some storms may become strong to severe.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not requested at this time, but spotters are
encouraged to submit reports of severe weather through the web by
going to weather.gov/atlanta. Please relay any information about
observed severe weather to the NWS.

Special Weather Statement
National Weather Service Peachtree City GA
721 AM EST Tue Jan 9 2024

GAZ042-052-053-066-091300-
Coweta GA-Carroll GA-Heard GA-Troup GA-
721 AM EST Tue Jan 9 2024

...Strong thunderstorms will impact portions of southeastern Carroll,
Heard, Troup and western Coweta Counties through 800 AM EST
...

At 721 AM EST, a line of strong thunderstorms was along a line
extending from near Woodland to near Welch to West Chambers, and
moving northeast at 40 mph.

HAZARD...40 mph wind and heavy rain.

SOURCE...Radar indicated.

IMPACT...Expect minor damage to tree limbs and blowing around of
         light, unsecured objects. Heavy rain may cause temporary
         street flooding especially in poor drainage areas.

Locations impacted include...
LaGrange, Franklin, West Point, Hogansville, Whitesburg, Ephesus,
Centralhatchee, Roopville, Corinth, Plant Yates, Cannonville, Seaton
Lake, Piedmont Heights, Harrisonville, Hillcrest, Wares Crossroads,
Glenn, Blackjack Mountain, Tyus, and State Line Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

People outdoors should seek shelter immediately. Motorists should
slow down and be prepared for possible loss of control due to
hydroplaning.

&&

LAT...LON 3356 8488 3327 8488 3291 8500 3287 8515
      3287 8518 3344 8530
TIME...MOT...LOC 1221Z 243DEG 35KT 3337 8535 3307 8538 3285 8549

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

Special Weather Statement
National Weather Service Peachtree City GA
752 AM EST Tue Jan 9 2024

GAZ052>054-066-067-078-091315-
Harris GA-Fayette GA-Coweta GA-Heard GA-Troup GA-Meriwether GA-
752 AM EST Tue Jan 9 2024

...Strong thunderstorms will impact portions of northwestern Fayette,
Meriwether, eastern Heard, Troup, Coweta and northern Harris Counties
through 815 AM EST
...

At 752 AM EST, a line of strong thunderstorms was along a line
extending from near Plant Yates to near Harrisonville to near River
View, and moving east at 45 mph.

HAZARD...40 mph wind and heavy rain.

SOURCE...Radar indicated.

IMPACT...Expect minor damage to tree limbs and blowing around of
         light, unsecured objects. Heavy rain may cause temporary
         street flooding especially in poor drainage areas.

Locations impacted include...
Newnan, LaGrange, Hamilton, Greenville, Peachtree City, Tyrone,
Palmetto, Senoia, Hogansville, Grantville, Pine Mountain,
Luthersville, Warm Springs, Moreland, Sharpsburg, Turin, Haralson,
Lone Oak, East Newnan, and Corinth.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

People outdoors should seek shelter immediately. Motorists should
slow down and be prepared for possible loss of control due to
hydroplaning.

&&

LAT...LON 3284 8515 3316 8506 3343 8500 3345 8496
      3344 8494 3346 8492 3351 8464 3350 8461
      3352 8458 3354 8450 3316 8458 3273 8474
      3274 8513 3276 8514 3278 8512 3283 8517
TIME...MOT...LOC 1252Z 263DEG 38KT 3345 8493 3314 8498 3275 8511

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

Preliminary Local Storm Report
National Weather Service Peachtree City GA
806 AM EST Tue Jan 9 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0530 AM     Non-Tstm Wnd Dmg 2 W Fairplay            33.62N 84.89W
01/09/2024                   Douglas            GA   Emergency Mngr

            One tree down at the intersection of Tyree
            Rd and Hwy 166.

&&

Special Weather Statement
National Weather Service Peachtree City GA
807 AM EST Tue Jan 9 2024

GAZ033-044-053>055-091330-
Fayette GA-North Fulton GA-Clayton GA-Coweta GA-South Fulton GA-
807 AM EST Tue Jan 9 2024

...A strong thunderstorm will impact portions of northern Fayette,
north central Coweta, northwestern Clayton and south central Fulton
Counties through 830 AM EST
...

At 807 AM EST, National Weather Service doppler radar indicated a
strong thunderstorm over Cannongate, or 8 miles northeast of Newnan,
moving northeast at 65 mph.

HAZARD...40 to 50 mph wind and increased chance of a brief tornado.

SOURCE...Radar indicated.

IMPACT...While winds should result in minor damage to tree limbs and
         blowing around of light, unsecured objects, this storm has
         also exhibited localized rotation. A brief tornado could
         quickly form.

Locations impacted include...
Atlanta, Jonesboro, City of South Fulton, Peachtree City, East Point,
Union City, Forest Park, Riverdale, College Park, Fairburn, Tyrone,
Hapeville, Palmetto, Lake City, Hartsfield-Jackson Airport, Cascade
Heights, Cannongate, Sandy Creek, Thomas Crossroads, and Madras.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

People outdoors should seek shelter immediately.

&&

LAT...LON 3339 8472 3349 8481 3376 8446 3366 8435
      3352 8436
TIME...MOT...LOC 1307Z 239DEG 56KT 3349 8469

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH

Special Weather Statement
National Weather Service Peachtree City GA
825 AM EST Tue Jan 9 2024

GAZ053>057-091400-
Fayette GA-Clayton GA-Coweta GA-Spalding GA-Henry GA-
825 AM EST Tue Jan 9 2024

...Strong thunderstorms will impact portions of northwestern
Spalding, Fayette, western Henry, southeastern Coweta and Clayton
Counties through 900 AM EST
...

At 825 AM EST, a line of strong thunderstorms was along a line
extending from near Riverdale to Fayetteville to Haralson, and moving
northeast at 45 mph.

HAZARD...40 mph wind and heavy rain.

SOURCE...Radar indicated.

IMPACT...Expect minor damage to tree limbs and blowing around of
         light, unsecured objects. Heavy rain may cause temporary
         street flooding especially in poor drainage areas.

Locations impacted include...
Griffin, Fayetteville, Jonesboro, Peachtree City, Stockbridge, Forest
Park, Riverdale, Hampton, Morrow, Lovejoy, Senoia, Lake City, Brooks,
Haralson, Woolsey, Sunny Side, Lake Spivey, Rex, Starrs Mill, and
Inman.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

People outdoors should seek shelter immediately. Motorists should
slow down and be prepared for possible loss of control due to
hydroplaning.

&&

LAT...LON 3343 8451 3353 8450 3364 8425 3363 8424
      3363 8423 3365 8422 3364 8419 3363 8418
      3359 8415 3358 8414 3355 8414 3324 8430
      3322 8463
TIME...MOT...LOC 1325Z 246DEG 38KT 3355 8446 3346 8447 3324 8459

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

Special Weather Statement
National Weather Service Peachtree City GA
827 AM EST Tue Jan 9 2024

GAZ078-079-089>091-091400-
Chattahoochee GA-Harris GA-Marion GA-Talbot GA-Muscogee GA-
827 AM EST Tue Jan 9 2024

...Strong thunderstorms will impact portions of northwestern Marion,
Muscogee, central Chattahoochee, western Talbot and southeastern
Harris Counties through 900 AM EST
...

At 827 AM EST, a line of strong thunderstorms was along a line
extending from near Cataula to Edgewood to Fort Mitchell, and moving
northeast at 60 mph.

HAZARD...40 mph wind and heavy rain.

SOURCE...Radar indicated.

IMPACT...Expect minor damage to tree limbs and blowing around of
         light, unsecured objects. Heavy rain may cause temporary
         street flooding especially in poor drainage areas.

Locations impacted include...
Columbus, Talbotton, Waverly Hall, Woodland, Geneva, Fort Moore,
North Fort Moore, Bibb City, Upatoi, Ellerslie, Laurel Hills,
Juniper, Vista Terrace, Cataula, Columbus Metropolitan Airport,
Baughville, Rose Hill, Eelbeck/West Fort Moore, Benning Hills, and
Avondale.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

People outdoors should seek shelter immediately. Motorists should
slow down and be prepared for possible loss of control due to
hydroplaning.

&&

LAT...LON 3238 8497 3239 8499 3239 8497 3241 8498
      3242 8496 3244 8497 3245 8500 3247 8500
      3266 8497 3284 8449 3265 8449 3242 8466
      3231 8498 3232 8500 3234 8501
TIME...MOT...LOC 1327Z 247DEG 50KT 3266 8491 3250 8493 3236 8502

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH