Severe Thunderstorm Warning 223, NWS Atlanta, GA

Area Forecast Discussion...Updated Aviation
National Weather Service Peachtree City GA
149 PM EDT THU JUL 21 2016

.Late Morning Update...
/Issued at 1005 AM EDT THU JUL 21 2016/
Morning sounding shows a very moist and unstable airmass in place...
with 1.72 pw's and a modified sounding for this afternoon producing
nearly 4000 J/KG of mucape. This coupled with an active north to nw
wind flow has warranted increasing area afternoon and early evening
pops into the 40-50 percent range for now. The moist airmass coupled
with some mid level dry air and relatively low wet bulb zero values
between 11k and 12k feet all suggest the main storm threats today
will be frequent lightning... locally heavy rain... pea to quarter
sized hail and the greater concern of 40-60+ mph downburst
winds...which would be sufficient to down a few trees and power
lines. SPC continues to show the SE in a Marginal Risk Area for
today... and this definitely looks reasonable. The strong to
potentially severe storms should begin to develop between 1 and 2 pm
this afternoon... and could occur just about anywhere today as
storms are mainly driven by their own outflows. The storm threat
should greatly diminish by 10-11 pm this evening with loss of
daytime heating. All interest are encouraged to monitor storms
closely later today and be ready to move indoors if thunder roars.
/39

.Previous Discussions.../Issued at 414 AM EDT THU JUL 21 2016/

SHORT TERM /Today through Friday/...
Upper ridge centered west of the MS river will continue as the
dominant weather feature across the forecast area with a general
northerly flow aloft. Convection should be mainly diurnal...lasting
into the evening. No obvious dynamics to focus convection next couple
of days...except maybe any remnant boundaries and the persistent
lee side trough. So have started with slight chance mid morning and
increased to chance by afternoon today and again Friday. SPC has
much of the area in a marginal risk for today. With abundant
heating and a moist air mass yielding afternoon capes of around 2000 to
2500 or more...a few storms could become strong to severe this afternoon
and evening.

Temperatures are basically persistence...highs mostly mid 90s. No heat
advisory planned for today...only an isolated area over central
GA may reach 105 heat index.

41

LONG TERM /Friday Night through Wednesday/...
A very stagnant pattern remains into the extended forecast with
not much change expected anytime soon. Large east to west
oriented upper ridge stays centered over the central and southern
plains and continues to be the main focus in this weather pattern.
This ridge does weaken a bit and becomes even more elongated
(west to east) through the end of next week...but it continues to
direct the over all flow around the central and mid-south states
through day 7. Moisture continues to rotate around the periphery
of the ridge with slight/chance pops expected everyday across
North and Central Georgia. Looking a bit past day 7...not seeing
any drying trends setting up so it appears we are in this diurnal
precip pattern for a while. There are also no signs of tropical
development in Atlantic basin. Temps also stay warm in the
extended with daytime highs mainly in the 90s and nighttime lows
in the upper 60s and 70s.

01

&&

.AVIATION...
18z Update...
Scattered showers and thunderstorms are already developing...
warranting a tempo tsra from 18z to 22z for all airports today...
and maybe beyond. Diurnally driven cumulus will produce sct mid
level clouds this afternoon and again on Friday. Some mvfr to ifr
stratus may be possible early Friday morning around areas that
receive much rainfall this afternoon/evening... especially around
CSG and MCN. Convection will dissipate around 02-04z this evening
and expect less coverage on Friday. Current light east to se winds
will remain east tonight... the veer se by 15-16z Friday... then
finally ssw by 20-21z Friday. Speeds will be 7kts or less.

//ATL Confidence...18Z Update...
Medium confidence on winds. High confidence remaining
elements.

39

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          96  72  96  74 /  40  30  20  10
Atlanta         95  74  95  75 /  40  30  20  10
Blairsville     89  66  91  68 /  40  30  30  10
Cartersville    95  72  95  73 /  40  30  20  10
Columbus        97  75  97  75 /  30  30  30  10
Gainesville     93  72  94  74 /  40  30  20  10
Macon           97  72  97  74 /  40  30  30  10
Rome            97  72  97  73 /  30  30  20  10
Peachtree City  96  71  95  72 /  40  30  20  10
Vidalia         96  73  97  74 /  30  30  30  10

&&

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

SHORT TERM...41/39
LONG TERM....01
AVIATION...39

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1020 AM EDT THU JUL 21 2016

GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-078>086-
089>098-102>113-221200-
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-
1020 AM EDT THU JUL 21 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH AND CENTRAL GEORGIA.

.DAY ONE...THIS AFTERNOON AND TONIGHT...
ISOLATED TO SCATTERED THUNDERSTORMS ARE EXPECTED OVER NORTH AND
CENTRAL GEORGIA...MAINLY BETWEEN 1PM AND 10PM. A FEW OF THESE
STORMS COULD BE STRONG TO SEVERE.

WEATHER HAZARDS EXPECTED...
WIND GUSTS BETWEEN 40 AND 60 MPH... FREQUENT LIGHTNING AND
LOCALLY HEAVY RAIN ARE THE MAIN STORM THREATS TODAY.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY...
SCATTERED THUNDERSTORMS WILL BE POSSIBLE EACH AFTERNOON AND
EVENING. SOME STORMS MAY PRODUCE ISOLATED AREAS OF DAMAGING
WINDS...FREQUENT LIGHTNING AND VERY HEAVY RAIN.

.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.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
159 PM EDT THU JUL 21 2016

GAZ053-211830-
COWETA GA-
159 PM EDT THU JUL 21 2016

...SIGNIFICANT WEATHER ADVISORY FOR COWETA COUNTY UNTIL 230 PM EDT...

AT 158 PM EDT...A STRONG THUNDERSTORM WAS OVER EAST NEWNAN...OR OVER
NEWNAN. THIS STORM WAS NEARLY STATIONARY.

  HAZARD...40 TO 50 MPH WIND AND HEAVY RAIN.

  IMPACT...PEOPLE OUTDOORS SHOULD SEEK SHELTER IMMEDIATELY. EXPECT
           MINOR DAMAGE TO TREE LIMBS AND BLOWING AROUND OF
           LIGHT...UNSECURED OBJECTS. MOTORISTS SHOULD SLOW DOWN AND
           BE PREPARED FOR POSSIBLE LOSS OF CONTROL DUE TO
           HYDROPLANING. ALSO...THE HEAVY RAIN MAY CAUSE TEMPORARY
           STREET FLOODING OR ROAD PONDING IN SLOW DRAINAGE AREAS.
           WHEN WATER COVERS THE ROAD...REMEMBER TO TURN AROUND
           DON'T DROWN.

SOME LOCATIONS IN THE PATH OF THIS STORM INCLUDE
NEWNAN...MORELAND...EAST NEWNAN AND ARNCO-SARGENT.

LAT...LON 3324 8472 3326 8490 3336 8491 3344 8485
      3343 8469 3334 8467
TIME...MOT...LOC 1758Z 180DEG 1KT 3335 8479