Area Forecast Discussion
Issued by NWS Atlanta, GA

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FXUS62 KFFC 291742
AFDFFC

Area Forecast Discussion...Updated for Aviation
National Weather Service Peachtree City GA
135 PM EDT Sat Apr 29 2017



.PREV DISCUSSION... /Issued 336 AM EDT Sat Apr 29 2017/

SHORT TERM /Today through Sunday/...

Warmer than normal temperatures will make it feel like the beginning
of Summer rather than Springtime today.

High pressure aloft and at the surface will continue off the
southeast coast Today and Sunday. Low level moisture will continue
to stream northward, but there are no synoptic surface features of
note to provide focus for any convection today or during the early
part of Sunday. However, with the good low level moisture and
heating, orographically induced convection will be possible.
Elsewhere, convection will have to be triggered by outflow boundaries
or any other mesoscale features...such as a differential heating
boundary. Forecast soundings show a decent capping inversion today
and a somewhat stronger one on Sunday - keeping the activity
isolated to scattered at best both days.

If convection does develop today, storms could be strong, with an
isolated severe storm possible. Forecast soundings do show a nice
inverted-v structure with steepening lapse rates. Gusty winds and
hail would be likely within any strong/severe storms that develop.

High temperatures today will average around 10 degrees above normal.

NListemaa

LONG TERM /Sunday Night through Friday/...

Still looking at two main systems impacting the extended forecast
period, late Sunday night and Monday and then later in the week
generally centered on Thursday.

Initial system Sunday night and Monday continues to look like it
brings at least a marginal risk for severe weather. Strong
southwesterly upper flow ahead of a fairly deep upper low points to
some potential before midnight, especially across the west. Main
threat approaches after midnight entering the far west before
daybreak as the associated cold front enters the state. Cold front is
progged to make steady progress across the forecast area through the
day Monday despite the parent surface low lifting well north into the
western Great Lakes. Medium range models continue to minimize the
instability somewhat as the system approaches Sunday night into early
Monday. MUCAPE values drop below 800 and 850-500mb lapse rates drop
to 6 degrees or less. Some diminished instability is to be expected
in the overnight period, but we will need to watch actual trends
closely. Nevertheless, with moderate low-level shear expected to
accompany the main area of convection, severe threat cannot be
ignored. Deeper layer shear appears to lag a bit behind main system
at this time. Moderate recovery to instability during the day Monday
as the system shifts into the eastern half of the forecast area and
moderate low-level shear maintains the severe threat.

A bit of a break behind this initial system through Wednesday before
the next system approaches by early Thursday. Will likely see a
return of isolated to scattered showers or thunderstorms as early as
Wednesday but main impacts are still centered on Thursday, lingering
into Friday. Still a bit of a spread between the main medium range
models concerning the exact track and timing of the surface and
upper-level features with this system but all show a good shot of
mild to cool air filling in behind the system going into the weekend.

20

CLIMATE...

Records for 04-29

               Max Temperature         Min Temperature
  Station      High        Low         High        Low
  -------  ----------  ----------  ----------  ----------
   KAHN      90 1915     50 1999     66 1975     38 1973
                                        1970        1928
   KATL      88 1894     47 1934     67 2014     39 1992
                                        1989
                                        1970
   KCSG      92 1943     57 1934     71 1970     39 1928
                1927
   KMCN      92 2012     50 1934     68 1970     37 1992
                                        1914


&&

.AVIATION...
18Z Update...
Expect SCT to BKN040-050 this afternoon with most cumulus dissipating
by 00z. MVFR stratocu should develop toward daybreak Sunday across
most of the forecast area...with some improvement to vfr by 15z.
Chance of thunderstorms still too low to mention through Sunday
afternoon...but will monitor to see if any convection should
threaten any of the taf sites. Winds should stay on the east side of
south this afternoon with a few gusts...however it is possible the
winds may go temporarily sw. Southeast winds increasing for Sunday.


//ATL Confidence...18Z Update...
High confidence all elements.

41


&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          87  66  85  68 /  20  20  10  50
Atlanta         86  68  84  67 /  20  10  10  60
Blairsville     83  62  78  62 /  30  30  30  60
Cartersville    87  67  84  66 /  20  10  10  70
Columbus        89  69  87  69 /  20  10   5  60
Gainesville     85  66  82  66 /  20  20  20  60
Macon           90  67  88  69 /  10   5   5  30
Rome            88  67  85  65 /  20  10  10  70
Peachtree City  87  65  84  66 /  20   5  10  60
Vidalia         91  69  88  70 /   5   0   5  20

&&

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

$$



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