Area Forecast Discussion
Issued by NWS Atlanta, GA
FXUS62 KFFC 300256
Area Forecast Discussion
National Weather Service Peachtree City GA
1056 PM EDT FRI JUL 29 2016
Afternoon/evening convective activity waned over the last few
hours only to redevelop in the last 30 minutes across west
central Georgia. Overall, short term models haven`t had a good
handle on the redevelopment, and have opted to keep slight chance
to chance pops in through 06z. Aside from updates to the pop/wx
grids and hourly temperatures, the overall forecast looks to be on
track and minimal adjustments were made. Latest model runs
continue to suggest better moisture Saturday will be across far
north Georgia and across middle and south Georgia.
.PREV DISCUSSION... /Issued 751 PM EDT FRI JUL 29 2016/
PREV DISCUSSION... /Issued 300 PM EDT FRI JUL 29 2016/
SHORT TERM /Tonight through Saturday Night/...
With the deeper moisture in place from roughly the ATL metro and
points northward...this is certainly the location for the most
concentrated TSRA activity this afternoon. And in fact...the
latest radar imagery is bearing this out as a decent cluster of
storms continues from Walker and Catoosa eastward to
Murray...Gilmer and Fannin. Expect this activity to build
southward along outflow boundaries through this evening but also
in response to the aforementioned deep moisture axis shifting
southward. May bump up pops along the extreme northern tier to
likely but otherwise the very near term in good shape with no
additional changes planned.
Given continued marginal CAPE and ample moisture...will carry some
slight chance pops into the very late evening hours but clear out
for the overnight period. Near uniform temps expected tonight
with lower 70s...except mid 60s over the NE mountains.
The moisture axis that is affecting North GA today shifts over the
central sections of GA for Saturday to include both Columbus and
Macon. Some drier air noted for the North where PW values dip to
1.50 inches across Atlanta but already recovering to 1.75 inches
by afternoon for the far NW. Highest pops will be associated with
this deep moisture and will carry high end chance pops for central
portions but mid levels remain very warm with -5C at 500mb. So
although storm coverage will increase...overall strength of
storms will remain benign. Exception may be those extreme NW
counties where mid level temps do decrease to around -7C late in
the day perhaps leading to a strong storm or two.
Will again be a close call for 90 degree days at ATL for Sat but
right now have a solid 92 in there for Sat.
LONG TERM /Sunday through Friday...
Long range begins with with a persistent but weak long wave trough
that stretches from the Great Lakes southward into TN Valley. This
feature and the associated subtle disturbances traversing through
the upper flow should help enhance our chances of mainly diurnally
driven convection through the weekend. Weak wind shear and moderate
instabilities suggest most afternoon and evening storms should
remain below severe limits... but with added upper support... cannot
rule out a few strong or isolated severe storms across mainly parts
of north GA over the weekend. By early next week it appears the
upper trough meanders slightly eastward as an upper ridge over TX
builds east. Although this may lesson our convective chances a
bit... still expect sufficient moisture and instability to support
at least a 30-40 percent pop each afternoon and evening... with 20-
30 percent warranted overnight.
The expected increase in clouds and rain chances should help hold
temps closer to seasonal normals over the weekend... then expect
another gradual warm up into mid next week with increasing high
pressure influence from the west.
Continued to include some mention of VCSH or TSRA at several
northern TAF sites as activity begins to wind down this evening.
Expect generally VFR through the period, except for FEW-SCT MVFR
after 12z. IFR cigs expected west of the area will be monitored.
MVFR cigs expected to improve to VFR by mid/late morning with
enough of a chance for convective activity to continue PROB30 for
20-00z for ATL to AHN and southward. Expect this to transition to
a VCSH rather than a TEMPO. West winds will be 6 kt or less
overnight, then increase to 7-10 kt through the day, with gusts
associated with convection.
//ATL Confidence...00Z Update...
High confidence on all elements.
.PRELIMINARY POINT TEMPS/POPS...
Athens 73 95 73 94 / 30 20 20 40
Atlanta 74 92 75 91 / 30 30 30 40
Blairsville 67 87 67 85 / 40 30 30 50
Cartersville 71 91 72 90 / 30 20 20 40
Columbus 75 95 75 94 / 20 40 30 30
Gainesville 72 91 73 90 / 30 20 20 40
Macon 74 96 74 95 / 20 40 30 30
Rome 71 92 72 91 / 30 30 20 40
Peachtree City 72 93 72 92 / 30 30 30 40
Vidalia 75 98 76 96 / 10 40 30 30