Severe Thunderstorm Warning 78, NWS Atlanta, GA

Area Forecast Discussion
National Weather Service Peachtree City GA
151 PM EDT Thu May 9 2019

.PREV DISCUSSION... /issued 1102 AM EDT Thu May 9 2019/

UPDATE...

Main issue in the short term will be the evolution of complex
currently moving into portions of Alabama. Hi res guidance is
split on solutions where shortwave drives convection and heads NE
and those that are keying on the cold pool to the south. Already
seeing some signs of weakening with the northern tier portion so
will need to monitor this trend closely. Regardless of how much
actual convection makes it this way, confidence increasing that
areas all the way to the Atlanta metro will see at least some
rainfall from this and have upped pops accordingly. Remainder of
the forecast looks on track and no additional changes planned.

Deese

PREV DISCUSSION... /issued 720 AM EDT Thu May 9 2019/

SHORT TERM /Today through Friday/...
Line of weakening convection across Alabama may bring some residual
showers into the northwest early this morning. Better chances for
more substantial convection will be late this afternoon into the
evening. Cold front gets hung up in the Mississippi Valley today but
hi-res models continue to show a moderate and persistent line of
convection moving into the northwest and west portions of the area
during the late afternoon and advancing at least into the I-85
corridor before weakening this evening. Best instability and lift
remain west of the state through this time frame, but will be
sufficient for strong to marginally severe thunderstorms into the
northwestern corner of the forecast area. Should see a bit of a lull
through the overnight period but good coverage of showers and
thunderstorms again Friday as the region remains under southwesterly
mid/upper flow and the cold front settles into the region.

20

LONG TERM /Friday Night through Wednesday/...
A stationary boundary across the southeast states will contribute to
unsettled weather for the weekend.

A stalled frontal boundary across northern GA will provide focus for
several rounds of convection through the weekend. At the beginning
of the period, the old frontal boundary should be situated just
south of the GA/NC/TN line. The models do push the boundary a bit
northward later Saturday into Sunday as a wave of low pressure moves
northeast along the boundary. The stronger wave of low pressure will
help drag the boundary through the remainder of the CWFA late Sunday
into early Monday. High pressure builds in for the remainder of the
long term period. Overall, there have been no major timing changes
to the forecast.

Not confident on how far north of the GA/TN/NC state line the
boundary will move, but the front should be close enough to the far
northern portion of the CWFA should retain the highest pops. In
addition, the axis of heaviest QPF remains in just about the same
place as yesterdays runs...mainly along and north of a Douglasville
to Atlanta to Athens line. However, the QPF values have increased,
especially across the highest elevations. Storm Total QPF from
Friday Night through Monday ranges from 1-2 inches north of
Interstate 20 with some locally higher amounts of 3-4 inches across
the higher terrain. South of I-20, values of an inch or less are
likely.

High pressure and drier conditions are anticipated for Tuesday
through Thursday. A brief return to more normal temps Monday and
Tuesday quickly moderate for the latter half of the week back to
above normal values.

NListemaa

&&

.AVIATION...
18Z UPDATE...

Winds at ATL have been flirting with SSW at ATL but this looks to
be fleeting and have kept them on the east side for now. VFR
conditions for now but a complex of storms and MVFR cigs poised
over Alabama will be headed for the terminals late this afternoon
into the evening hours. After 22Z looks to be the most favorable
timing for now and will include a TEMPO for all sites with MCN and
AHN just a few hours later with the TEMPO. Low cigs to develop in
the wake of this activity and have added in a period of IFR for
Friday morning for most sites.

//ATL CONFIDENCE...18Z UPDATE...
Medium on TSRA timing and IFR.
High on remaining elements.

Deese

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          83  65  83  66 /  30  40  50  40
Atlanta         83  67  82  67 /  60  70  60  40
Blairsville     76  61  77  61 /  50  60  60  60
Cartersville    82  65  81  64 /  60  70  60  50
Columbus        86  68  86  69 /  50  60  50  30
Gainesville     81  64  81  65 /  40  50  60  50
Macon           86  66  86  67 /  20  40  40  40
Rome            82  64  81  64 /  70  70  60  60
Peachtree City  83  65  83  66 /  60  70  60  40
Vidalia         86  68  87  68 /  20  20  40  20

&&

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

SHORT TERM...Deese
LONG TERM....NListemaa
AVIATION...Deese

Hazardous Weather Outlook
National Weather Service Peachtree City GA
1000 AM EDT Thu May 9 2019

GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086-
089>098-102>113-101000-
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-
1000 AM EDT Thu May 9 2019

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

.DAY ONE...This afternoon and Tonight...

Scattered to numerous thunderstorms are expected over portions of
north and central Georgia this afternoon into tonight.
A few storms will be strong and possibly severe over portions
of north and west Georgia. The main hazards will be strong and
possibly damaging winds, frequent lightning and heavy rain.

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

There is a chance of thunderstorms across the area
Friday into early Monday, with the greatest coverage on Saturday
and Sunday. A few storms could be strong and possibly severe with
gusty winds and frequent lightning. Heavy rainfall will also be
possible, especially across far north Georgia where localized
flooding could occur.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed through tonight.