Severe Thunderstorm Warning 235, NWS Atlanta, GA

Area Forecast Discussion
National Weather Service Peachtree City GA
1041 AM EDT Tue Jul 21 2020

.UPDATE...

Only a couple minor tweaks were made to the overnight forecast
package. Forecast remains on track with showers and thunderstorms
expected this afternoon and evening. Current radar already shows a
thunderstorm across far northern Georgia. Expecting the trend to
continue through the evening with the best coverage expected
across northern Georgia. Some storms may also become strong to
isolated severe across the entire forecast area, but most so
across northern Georgia where there is a Marginal Risk of severe
storms. The main hazard will be gusty winds, but periods of heavy
rain, hail, and frequent lightning will all be possible in any
stronger storms.

Reaves

&&

.PREV DISCUSSION... /Issued 720 AM EDT Tue Jul 21 2020/

SHORT TERM /Today through Wednesday/...

Weak upper ridging continues through the period. As has been the
case over the past several days, this upper ridging not strong
enough to suppress diurnal convection given the strong surface
heating again today and Wednesday. Shear remains minimal and little
or no mid/upper-level support, but strong diurnal heating builds
moderate instability and a few strong to severe storms are possible.
Best coverage expected across the north each day, tapering to more
isolated coverage across central Georgia.

Heat index values will push into the upper 90s to lower 100s again
today and Wednesday. Should remain below Heat Advisory levels across
the majority of the area each day, but portions of central and east
Georgia will need to be watched closely each day in case localized
values at or slightly above criteria become more widespread.

20

LONG TERM /Wednesday Night through Monday/...

The long term period begins monitoring closely the Gulf of Mexico
as the GFS indicates tropical moisture increasing with a wave.
Initially, this moisture remains well south of the local area with
no influence on the diurnal convective trends. In fact, area
remains in between large scale systems as for yet another run, the
GFS keeps front north of the area for another day. Despite the
best surface convergence remaining north of the area, increased
instability across the northern tier and precipitable water
approaching 2 inches warrants likely pops.

As mid and upper level ridge gets shunted west, a NW flow regime
develops across the area which will aid in the progression of
backdoor front through the northern sections. Eastern tier will
see deep layer moisture increase further and although instability
may be limited by abundant cloud cover, still sufficient values
to allow for likely pops for a portion of the area once again.

The remainder of the long term will depend both on the evolution
of the tropical moisture in the Gulf but also on far frontal
boundary will make it through the state. GFS still the most
aggressive in brining dry air in from the NE and substantially
reducing pops across the North on Saturday. Will lean toward the
NBM through the weekend which has more generic mid range pops for
the entire area except portions of Central GA where likely pops
will be carried.

Deese

AVIATION...
12Z Update...

VFR conditions are expected to predominate across the forecast area
through the forecast period. Periods of local MVFR or lower
visibilities are possible through 14Z. Isolated to scattered showers
and thunderstorms are expected, best coverage will be between 20Z
and 02Z. Winds will remain light and somewhat variable in direction.
Wind speeds will be 5kt or less through 14Z, increasing to 5-8kt
from the southeast to southwest after 14Z.

//ATL Confidence...12Z Update...

Medium on wind direction and overall convective coverage.
High on all else.

20

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          98  74  96  72 /  40  30  40  20
Atlanta         95  76  93  73 /  50  30  40  20
Blairsville     88  68  86  67 /  60  30  60  30
Cartersville    96  73  94  72 /  50  30  50  30
Columbus        97  77  96  75 /  40  20  30  10
Gainesville     94  74  92  72 /  50  30  50  30
Macon           98  74  97  73 /  30  20  30  10
Rome            97  73  95  72 /  50  30  60  20
Peachtree City  95  73  93  72 /  50  30  40  20
Vidalia         97  76  95  74 /  20  20  30  10

&&

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

SHORT TERM...20
LONG TERM....Deese
AVIATION...20

Hazardous Weather Outlook
National Weather Service Peachtree City GA
1203 PM EDT Tue Jul 21 2020

GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086-
089>098-102>113-221615-
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-
1203 PM EDT Tue Jul 21 2020

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

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

Scattered thunderstorms will develop once again this afternoon. A
few strong to potentially severe storms will be possible with
damaging winds, large hail, locally heavy rain, and frequent
cloud to ground lightning being the main threats with any storms
this afternoon and evening. The main focus for storms will be
across the far northern sections.

Heat indices will briefly reach 105 degrees across portions of
Central Georgia this afternoon.

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

Scattered to numerous thunderstorms are expected across the area.
A few storms may be strong to severe with damaging winds,
frequent lightning, hail and locally heavy rainfall.

Heat index values of 100 to 105 degrees can be expected over much of
the area outside of the mountains through Friday.

Special Weather Statement
National Weather Service Peachtree City GA
1214 PM EDT Tue Jul 21 2020

GAZ006-008-211645-
Union GA-Fannin GA-
1214 PM EDT Tue Jul 21 2020

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN UNION AND
SOUTHEASTERN FANNIN COUNTIES UNTIL 1245 PM EDT...

At 1213 PM EDT...a strong thunderstorm was over Dial, or near Blue
Ridge...moving east at 10 mph.

  HAZARD...40 to 50 mph wind...pea sized hail and frequent cloud to
           ground lightning.

  IMPACT...Expect minor damage to tree limbs and blowing around of
           light...unsecured objects.

Some locations in the path of this storm include
Morganton, Suches, Dial, Hemp, Margret, Hurst, Jones Creek and
Gaddistown.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

People outdoors should seek shelter immediately. If you can hear
thunder...you are close enough to be struck by lightning.

LAT...LON 3482 8395 3473 8396 3472 8398 3468 8399
      3467 8401 3469 8423 3471 8425 3472 8425
      3472 8426 3473 8426 3480 8431 3481 8433
      3482 8434 3492 8414
TIME...MOT...LOC 1613Z 258DEG 9KT 3480 8424

HAIL...0.25IN
WIND...50MPH

Special Weather Statement
National Weather Service Peachtree City GA
1250 PM EDT Tue Jul 21 2020

GAZ008-211715-
Union GA-
1250 PM EDT Tue Jul 21 2020

...SIGNIFICANT WEATHER ADVISORY FOR EASTERN UNION COUNTY UNTIL 115 PM
EDT...

At 1249 PM EDT...a strong thunderstorm was over Vogel State Park, or
8 miles south of Blairsville. This storm was nearly stationary.

  HAZARD...40 to 50 mph wind...up to penny sized hail...frequent
           cloud to ground lightning and heavy rain.

  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.

Some locations in the path of this storm include
Owltown, Woods Hole Shelter, Blood Mountain Shelter, Vogel State
Park, Low Gap Shelter and Track Rock.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

People outdoors should seek shelter immediately. If you can hear
thunder...you are close enough to be struck by lightning. Motorists
should slow down and be prepared for possible loss of control due to
hydroplaning.

LAT...LON 3487 8387 3478 8382 3477 8383 3474 8382
      3473 8383 3472 8386 3473 8387 3472 8389
      3473 8390 3474 8394 3472 8398 3480 8402
TIME...MOT...LOC 1649Z 249DEG 3KT 3476 8391

HAIL...0.75IN
WIND...50MPH