Severe Thunderstorm Warning 313, NWS Atlanta, GA

Area Forecast Discussion
National Weather Service Peachtree City GA
206 PM EDT Thu Jul 20 2023

...New 18Z Aviation Discussion...

.SHORT TERM...
(Today through Friday)
Issued at 354 AM EDT Thu Jul 20 2023

Current satellite loop shows mostly clear skies across the region.
Expecting another day of isolated to scattered showers and
thunderstorms but they should stay mainly across Northern and
Eastern portions of the state. Latest model runs indicating showers
and thunderstorms moving SE out of eastern TN later this morning
into the afternoon hours. The Hi-res models seem to have come into a
bit better agreement with timing and locations of these storms but
still differ a bit on intensity. We could certainly see some
isolated severe storms and even an organized line of storms across
eastern GA. These storms will be capable of producing damaging wind
gusts, frequent lightning strikes and periods of heavy rain aligning
mainly with the Slight Risk across North and portions of East GA.

Heat is the other thing to consider. Expecting Temps across central
GA today to get up into the upper 90s to lower 100s. With increased
dewpoints this will put our Apparent Ts in the 105 to 110 degree
range across most of Central GA. There is still some uncertainty if
we will hit these temps as we are expecting increased rain chances.
Still continuing the Heat advisory and have added a few more
counties across west central GA.

01

&&

.LONG TERM...
(Friday night through Wednesday)
Issued at 354 AM EDT Thu Jul 20 2023

Key Messages:

 - A frontal boundary moving south through north Georgia Friday
   will stall over central Georgia Saturday.

 - Slightly below average temperatures are forecast for the
   weekend, with highs in the mid to upper 80s and lows in the 60s
   over north Georgia.

Extended period weather pattern remains dominated by large ridge
over the southwestern US and deepening upper level trough over the
eastern CONUS. Short term frontal boundary will progress
southward and stall over central Georgia Friday night and
Saturday. Showers and thunderstorms will continue into the Friday
night periods. Coverage and severity are conditional on lingering
daytime heating, cloud cover, early development, etc, but a few
strong storms may linger into the late evening hours. SPC has the
majority of the state outlooked for a Marginal Risk (level 1 of
5), and at this time the primary concern continues to be damaging
winds.

Model consensus continues to keep stalled front in position over
central Georgia through the weekend, allowing the benefits of the
cooler air mass behind the front to be confined to the northern
half of the state. Temperatures will top out in the mid to upper
80s with lows in the 60s. The stalled boundary will provide a
focus for shower and thunderstorm development for central Georgia,
and precip activity and cloud cover should help keep temperatures
in the low 90s.

By next week, eastern CONUS trough retreats north and pressure
rises over the region. Temperatures rebound back into the low
90s by Monday, but a full moisture return appears delayed to
midweek or later as ensembles continue to show below normal PWAT
values over the area. Although forecast grids do include some
low-end PoPs Monday through Wednesday, suspect moisture will be a
limiting factor.

31

&&

.AVIATION...
(18Z TAFS)
Issued at 145 PM EDT Thu Jul 20 2023

Challenging forecast. Storms in TN expected to slide to the south
over time, with multiple waves forming and moving into N and E GA.
TAF sites in metro ATL are right on border of being impacted by
these waves, so uncertainty in impacts is high. Best estimates of
impact times would be 22Z-02Z today, 06-10Z and after 18Z
tomorrow. Otherwise, winds will be gusty at times, W to SW at
6-12 kts through period, with gusts up to 20 kts. SCT cu in place
today and tomorrow, going SCT to BKN higher clouds overnight.
Lower BKN deck near 040 or 050 possible with any storms that move
through.

//ATL Confidence...18Z Update...
Low confidence timing and occurrence of TSRA/SHRA across most
periods, high all others.

Lusk

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          73  93  71  87 /  40  40  30  40
Atlanta         76  94  72  87 /  30  50  40  40
Blairsville     66  84  63  80 /  60  50  40  30
Cartersville    73  91  69  86 /  40  60  40  30
Columbus        78  98  76  92 /  10  40  30  60
Gainesville     73  91  70  87 /  50  40  30  30
Macon           77  98  74  91 /  20  40  30  50
Rome            73  90  70  87 /  40  60  40  30
Peachtree City  73  94  71  87 /  20  40  40  40
Vidalia         77  98  76  92 /  20  40  30  60

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM EDT this evening for GAZ039-049>051-
058>062-066>076-078>086-089>098-102>113.

&&

SHORT TERM...01
LONG TERM....31
AVIATION...Lusk

Hazardous Weather Outlook
National Weather Service Peachtree City GA
1236 PM EDT Thu Jul 20 2023

GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086-
089>098-102>113-211645-
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-
1236 PM EDT Thu Jul 20 2023

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

.DAY ONE...This Afternoon and Tonight...

A Heat Advisory has been issued for areas generally along and
south of a line from LaGrange to Monticello, to Washington. Heat
Index values up to 108 are expected. Take extra precautions to
stay hydrated and limit time outdoors.

There is a Slight Risk (level 2 of 5) of severe weather today. A
thunderstorm complex will move through northern and central
Georgia between 3 PM and midnight tonight. The strongest storms
with this complex may produce damaging winds, frequent lightning
and periods of heavy rain.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday...

Thunderstorms will be possible in the region through next
Wednesday. Storms may become more widespread in the state Friday
afternoon into Saturday, then the greatest coverage is expected
over central and southern Georgia Sunday through Wednesday.
Isolated severe storms, particularly with damaging downburst
winds, could occur through Saturday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not requested 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.