Area Forecast Discussion
Issued by NWS Atlanta, GA

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786
FXUS62 KFFC 241447
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
1047 AM EDT Mon Jul 24 2017



.UPDATE...
This morning the atmosphere is characterized by a notable
shortwave trough over the central Great Lakes...with associated
cyclonic flow extending as far south as the central Appalachians.
Down at the sfc...a broad area of low pressure was noted across
the Mid Atlantic/southern New England...with two center areas of
low pressure across NJ and Lake Ontario. A trough extends from the
NJ low into north Georgia...while the Lake Ontario low features a
weak cold front extending through southern OH and SW into AR.

Comparing this analysis to GOES-16 imagery and latest model data...
models are already too far south with the drier air behind the
weak cold front. This means a high theta-e airmass will remain in
place across all of Georgia today. 12z FFC sounding shows an
unstable and very moist profile...with approximate convective temp
in the mid 80s. As with yesterday...pinpointing where convection
will develop is near impossible given possible lingering
boundaries from yesterday and last night...however think coverage
will be greatest near and ahead of the weak sfc trough. expect to
see some showers pop up in the next hour as cu field continues to
develop. Still potential later this afternoon for some strong
downdrafts as lower lapse rates increase and PW values flirt with
2 inches.

Kovacik

&&

.PREV DISCUSSION... /Issued 730 AM EDT Mon Jul 24 2017/

PREV DISCUSSION... /Issued 413 AM EDT Mon Jul 24 2017/

SHORT TERM /Today through Tuesday/...

An area of showers and thunderstorms that has been slowly dropping
through Tennessee toward the Georgia border has been gradually
diminishing in intensity this morning. A few showers and isolated
thunderstorms continue to develop along the leading edge of this
activity in far north Georgia at this time. While this diminishing
trend is expected to prevail overall, this area will continue to be
favored for additional shower or thunderstorm development this
morning.

Lingering boundaries from this morning`s activity will continue to
meander southward through this afternoon. These boundaries as well
as any remaining boundaries from Sunday evening convection will
serve as a focus for convective development during the heating of
the day today. Showers and thunderstorms will be largely diurnal in
nature, peaking in coverage and intensity during the late afternoon
and evening before beginning to diminish after sunset. A few strong
or isolated severe thunderstorms cannot be ruled out with afternoon
CAPE peaking over 2000 J/kg. Additionally, with continued high PWATs
at or above 2 inches, locally heavy rainfall can again be expected.

Tuesday will not bring any major changes to the forecast as the weak
frontal boundary stalls across central Georgia. This boundary will
again serve as a focus for diurnal convection with the highest
coverage expected to be in central Georgia Tuesday afternoon.

Temperatures will remain warm and muggy with highs ranging from the
upper 80s to low 90s and dewpoints well into the 70s.

RW

LONG TERM /Tuesday Night through Sunday/...

As the long term period begins...the forecast area remains on the
edge of the Bermuda high and in a weak upper trough. A frontal
boundary gets pushed into north GA early in the period and some
drying can be noted for a portion of the north. However not seeing
enough drying to remove pops completely...and we should expect a
continuation of mainly diurnal showers and thunderstorms. By
Saturday a long wave trough developing over the eastern states
should push another front southward into GA. However GFS and ECMWF
keep cyclonic flow over the southeast through the weekend. So have
continued with persistence pops. Temperatures should range around
normal numbers through the period.

41

AVIATION...
12Z Update...
A few isolated showers near ATL area TAF sites this morning are
diminishing in overall coverage at this time. While a couple of
isolated showers remain possible this morning, the greatest
convective coverage will increase this afternoon into this
evening, especially after around 18z. While VFR ceilings remain
at most locations, localized areas of MVFR or IFR ceilings are
possible through around 14z. Winds will remain from the west side
through the period.

//ATL Confidence...12Z Update...
Medium confidence on isolated morning convection and localized low
ceilings. High confidence on other elements.

RW

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          91  73  91  72 /  40  30  40  30
Atlanta         90  74  89  73 /  50  40  40  30
Blairsville     87  67  87  66 /  20  20  30  20
Cartersville    89  72  90  71 /  40  30  40  20
Columbus        92  75  89  74 /  60  40  60  30
Gainesville     89  73  89  72 /  30  20  40  30
Macon           93  75  89  73 /  50  40  60  30
Rome            90  72  91  72 /  40  20  30  20
Peachtree City  91  72  88  72 /  50  30  50  30
Vidalia         92  74  90  74 /  40  30  60  30

&&

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

$$

SHORT TERM...Kovacik
LONG TERM....Deese
AVIATION...Kovacik



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