Area Forecast Discussion
Issued by NWS Atlanta, GA
FXUS62 KFFC 291900
Area Forecast Discussion
National Weather Service Peachtree City GA
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.
.AVIATION... 18Z UPDATE...
Best chances for TSRA will be across the northern most sites today
including ATL where TEMPO for storms this afternoon still looks on
target. Given some winds noted in the low levels...any storms that
form today will be capable of gusty winds and therefore included
these in the TEMPo as well. Otherwise...IFR cigs tonight look to
remain just west of the area although close enough that it will
need to be monitored closely. Drier air in store for Sat but still
enough to warrant a Prob30 at this point. This may end up
transitioning to a VCSH as opposed to a TEMPO.
//ATL CONFIDENCE...18Z UPDATE...
Medium on TSRA potential.
High on remaining elements.
.PRELIMINARY POINT TEMPS/POPS...
Athens 72 93 74 94 / 30 30 30 40
Atlanta 73 90 75 91 / 40 40 30 40
Blairsville 69 88 68 85 / 40 40 40 50
Cartersville 72 91 72 90 / 40 40 30 40
Columbus 75 95 75 94 / 30 30 30 30
Gainesville 73 91 73 90 / 40 40 30 40
Macon 73 96 74 95 / 20 30 30 30
Rome 72 91 72 91 / 40 40 30 40
Peachtree City 72 92 72 92 / 40 40 30 40
Vidalia 75 98 75 96 / 20 30 20 30