Special Weather Statement, NWS Atlanta, GA

Area Forecast Discussion
National Weather Service Peachtree City GA
252 PM EDT Thu Aug 24 2023

...Afternoon Area Forecast Discussion...

.SHORT TERM...
(This afternoon through Friday)
Issued at 240 PM EDT Thu Aug 24 2023

At a glance:

	- Unseasonably hot conditions to continue, with a Heat Advisory in
      effect from noon to 8PM Friday.

	- Low-end chances for isolated thunderstorms north of I-20 this
      evening, and west of I-75 tomorrow, will provide no relief from
      highs in mid-to-upper 90s to near 100.

The mid-level ridge that has stagnated across the midsection of the
country for the past several days will slowly begin to lose its
influence over the Southeast as it begins to retrograde westward and
become more interspersed with pockets of moisture (with an overall
weakening effect -- from 603dam to 594dam). At the surface, much of
Georgia will be experiencing the final vestiges of the weak "cold"
air damming that percolated across the area yesterday. Surface
winds will continue to swing westward through this evening,
cutting off access to the slightly drier wedge airmass, but enough
lingers to temper heat index values for this afternoon to below
advisory criteria. Portions of northwest Georgia may see patchy
"feels like" temperatures around 105F this afternoon due to
blocking of drier air by terrain to the east, but expect this to
remain isolated enough in nature that Heat Advisory issuance will
not be necessary. That said, it will still be hot enough along and
north of the I-85 corridor to warrant increased caution if
spending extended periods of time outdoors. Highs look to top out
in the mid-90s today areawide, just about 5-10 degrees above
average for late August.

Confidence is increasing that a passing plume of moisture
rounding the eastern edge of our mid-level ridge, when combined with
lift from a residual outflow boundary associated with the morning
complex of showers and storms across the Ohio River Valley, will
have enough oomph to force a wave of southwest-propagating showers
and thunderstorms late this afternoon. HiRes guidance historically
struggles to resolve systems with this storm motion, but HREF probs
currently show 20-30% chances of receiving >= 0.01" of rainfall for
areas east of the AL/GA border and north of I-20. Not expecting much
in the way of severe weather by any means, especially given nearly
negligible shear under the influence of the ridge, but hot high
temperatures will support DCAPE as high as 1500 J/kg. *If* the quasi-
line holds together, cannot rule out an isolated strong to
marginally severe gust.

Moving into Friday, oppressive heat returns with a vengeance. Little
changes expected synoptically, but we'll see a resurgence of
moisture throughout the column as the eastern edge of the mid-level
ridge continues to retreat westward. Currently forecasting dewpoints
in the mid-70s coupled with unseasonably hot highs in the upper-90s
to lower-100s (10-15 degrees above climo). This translates to Heat
Index values in the 100-108F range effectively statewide, apart
from the terrain of NE Georgia. Have gone ahead with Heat Advisory
issuance for Friday given high confidence in at least meeting the
aforementioned values, valid through 8PM Friday evening.

96

&&

.LONG TERM...
(Saturday morning through next Wednesday)
Issued at 240 PM EDT Thu Aug 24 2023

Key Messages:

 - Hot conditions will persist through the weekend with Heat
Advisories possible (60% chance) for at least a portion of the
region Saturday and Sunday.

 - As the current heat wave falters, rain and thunderstorm activity
should become more widespread in the region next week.

 - We are monitoring the potential (50% chance of development) for a
tropical system in the eastern Gulf of Mexico early next week.

Heat Concerns Saturday, Sunday & Monday:

The primary update to our forecast over the last 24 hours has been
to extend the period of potentially hazardous heat into Monday for
portions of central Georgia (generally south of the Atlanta Metro).
Decreasing confidence in the ability of a frontal boundary clear the
region on Monday is the main driver behind this shift in the
temperature outlook. Other factors affecting the temperature
forecast through Monday remain relatively unchanged. The strong
upper level ridge over the Central Plains should still weaken and
push towards the Four Corners. As this occurs it will allow a blob
of anomalously warm 850 mb temperatures (5-8 degrees C above
average) to shift from the Upper Midwest to the Southeast.

Excluding the higher elevations in far northern Georgia, surface
temperatures should peak in the 96 to 103 degree range Saturday
afternoon. Toss in surface dewpoints near 70 degrees and we get heat
indices in the 101 to 108 degree range for Saturday afternoon.
Temperature declines of 1 to 3 degrees are anticipated Sunday, but
the heat will remain oppressive. Monday will be all about the
position of the aforementioned frontal boundary. Due to the
hazardous heat potential, Heat Advisories are possible (60% chance or
greater) for a portion of northern and central Georgia both Saturday
and Sunday. Confidence in Heat Advisory conditions would be higher
if there was greater confidence in the surface dewpoint forecast.
Anyone with outdoor activities planned should anticipate the need to
take measures to mitigate the heat.

Rainier Pattern Next Week:

The forecast for next week remains complex. Early in the week
(Sunday through Tuesday) the main driver of our forecast looks to be
a stationary front draped from west to east across the region.
Wherever this feature sets up, it should be a focal point for
enhanced precipitation chances. As we progress into the middle part
of the workweek (Tuesday to Thursday), concern shifts towards
potential tropical activity in the eastern Gulf of Mexico and a cold
front/upper level trough combo arriving from the northwest. The
timing of the cold front/upper level trough will be critical for our
region. An early arrival could end up "shielding" us from any
tropical nonsense, while a slower passage would leave the door
cracked open. For now the consensus in the ensemble guidance (EPS,
GEFS & CMCE) favors a front passage on Wednesday. If this holds, any
tropical moisture would likely be focused over south Georgia and
Florida.

As things stand, expect rain chances to begin to inch upward in
northern and central Georgia on Sunday. Peak rain chances of 40 to
60% are then expected in northern and central Georgia Monday and
Tuesday. The greater rain potential may linger in central Georgia
Wednesday, before drier air filters in and rain chances decline
heading into next weekend.

Given the higher rain chances, multiple frontal passages and
potential troughing aloft, we can anticipate heat being less of a
concern next week. Our going forecast has highs drifting back towards
the mid and upper 80s, which would be within 2 or 3 degrees of
seasonal averages for late August.

Albright

&&

.AVIATION...
(18Z TAFS)
Issued at 136 PM EDT Thu Aug 24 2023

Expect VFR conditions to continue thru the TAF pd. Low chc of
seeing TSRA at northern terminals between 22-02Z, but have
retained TAF mention for planning purposes. Winds will be 6kts or
less thru the eve and may become CALM/VRB overnight. Overall,
winds will continue to favor the W side, and should pick up out
of the NW areawide aft 14Z tomorrow.

//ATL Confidence...18Z Update...

Low confidence direct TSRA impacts at northern terminals.
High confidence all other elements.

96

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          71  98  73  98 /  10  10   0  20
Atlanta         72  98  75  99 /  20  10   0  10
Blairsville     67  91  68  91 /  10  10   0  20
Cartersville    71  97  72  97 /  20  10   0  10
Columbus        74 100  76 102 /  10  20  10  10
Gainesville     72  97  73  98 /  10  10   0  20
Macon           72  99  75 100 /  10  20  10  10
Rome            72  98  72  98 /  20  10   0  10
Peachtree City  70  97  73  98 /  20  10   0  10
Vidalia         72  98  75 101 /   0  10  10  20

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from noon to 8 PM EDT Friday for GAZ001>005-011-
012-019-020-023>025-027-030>039-041>062-066>076-078>086-089>098-
102>113.

&&

SHORT TERM...96
LONG TERM....Albright
AVIATION...96

Hazardous Weather Outlook
National Weather Service Peachtree City GA
1147 AM EDT Thu Aug 24 2023

GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086-
089>098-102>113-251600-
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-
1147 AM EDT Thu Aug 24 2023

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

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

Isolated thunderstorms are possible north of I-20 late this
afternoon and evening. Brief heavy downpours, frequent lightning,
and gusty winds will be possible in any storms that develop. The
overall severe risk remains low at this time.

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

Hazardous heat will return Friday, Saturday and Sunday as heat
index values climb back into the 100 to 108 degree range. Heat
Advisories may become necessary for a portion of the region during
this period. If you have outdoor activities planned, be prepared
to take measures to mitigate the risk of heat related illnesses.

Thunderstorms chances will then gradually rise through early next
week, with the most widespread activity anticipated Monday and
Tuesday. At this time the risk for severe weather remains low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed through tonight.

Special Weather Statement
National Weather Service Peachtree City GA
404 PM EDT Thu Aug 24 2023

GAZ023>025-242030-
Hall GA-Banks GA-Jackson GA-
404 PM EDT Thu Aug 24 2023

...A strong thunderstorm will impact portions of Banks, northeastern
Hall and north central Jackson Counties through 430 PM EDT...

At 404 PM EDT, a strong thunderstorm was over Mount Airy, or 8 miles
southeast of Clarkesville, moving south at 15 mph.

HAZARD...Up to 40 mph wind, frequent cloud to ground lightning 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...
Homer, Lula, Maysville, Clermont, Gillsville, Pinefield Crossroads,
and Hollingsworth.

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 3450 8378 3450 8367 3443 8361 3449 8352
      3446 8340 3442 8338 3432 8339 3428 8336
      3425 8356 3426 8375 3450 8380 3450 8379
      3452 8379
TIME...MOT...LOC 2004Z 353DEG 14KT 3450 8346

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