Area Forecast Discussion
Issued by NWS Atlanta, GA

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FXUS62 KFFC 230200 AAB
AFDFFC

Area Forecast Discussion...UPDATED
National Weather Service Peachtree City GA
1000 PM EDT Mon May 22 2017

.UPDATE...
No changes to the forecast. Showers increasing tonight with
some storms. Flash Flood watch continues.

BDL

&&

.PREV DISCUSSION... /Issued 710 PM EDT Mon May 22 2017/

SHORT TERM /Tonight through Tuesday Night/...
Surface boundary has become nearly stationary with convection
developing in the vicinity of the front and also areas southward.
These showers and tstorms appear to be pretty efficient rain
producers with PWATS of 1/5 to 2 inches across most of the CWA
through tonight. With the front lingering and the second short wave
moving across the CWA tonight, thinking that the QPF amounts may be
a bit too low but confidence in raising them is not quite there yet.
Having said that, still think there is a risk of isolated flash
flooding tonight and will therefore maintain the Flash Flood Watch.
The short wave will exit the CWA Tuesday bringing a brief respite to
the CWA. The h5 trough and will continue to dig southward and eject
a strong cold front that will move into the CWA late Tuesday
night/early Wednesday morning. QPF amounts are not as great with
this, however instabilities increase with CAPES increasing ahead of
the cold front as well as lapse rates and 6km bulk shear. This
should bring a risk of isolated severe storms late Tuesday night
across mainly the western parts of the CWA.

17

LONG TERM /Wednesday through Monday/...
No changes made to the extended forecast. The extended period
starts off with the GFS and NAM both increase deep layer shear
going into the Wed morning hours which is juxtaposed with the
left exit region of the 250mb jet. Models are more sporadic and
broad with QPF in this period so confidence is medium on how
things will evolve...especially given the unknown impact of the
first wave moving through Tuesday AM. For now have kept pops in
the likely category and included thunder as well. May see a fairly
stout line of convection develop in the eastern half of the state
late Wed AM into the afternoon as models forecast additional
destabilization during the day.

Of greater note is the 00z ecmwf solution with an upper low
cutting off much further south than previous solutions over
Central AL and shifting eastward across GA on Thu. GFS is much
further north with the cut off portion...but does extend the base
of the trof into the same general area. GFS and ECMWF 500 mb temps
with the low/trof drop to -21 to -22 across the region on thu.
Sounding climatology suggests that those temps would be one of and
very close to the coldest on record for May at ATL should it
occur...and most certainly a record for the date. In
response..afternoon highs both Wed and Thu are forecast to remain
in the low 70s which is right around record low max temps.
Overnight lows drop into the low 50s Thu AM and Fri AM as well and
while much below normal and cool...records are generally in the
40s.

Nice weather on tap through Sunday before another trof digs into the
central US and rain chances again increase in response.  Models vary
on the evolution of the trof...but agree that one is forecast to
return.

30/01

AVIATION...
00Z Update...
Low confidence forecast with widely varying conditions possible
through the period. Potential for IFR ceilings overnight as well
as another surge of showers and at least some storms with mvfr
vsbys most likely in the showers and possibly brief IFR vsbys.
Conditions improving during the day to MVFR-VFR. Surface winds
mainly light and variable but potential to shift to the ENE before
going back to the WSW during the day Tuesday.

//ATL Confidence...00Z Update...
Medium confidence for wind speeds.
Low confidence for all other elements.

BDL

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          66  77  64  76 /  90  90  70  70
Atlanta         66  77  65  75 /  90  80  70  70
Blairsville     61  72  59  69 /  90  70  70  80
Cartersville    65  78  64  74 /  90  70  70  70
Columbus        69  79  67  78 /  90  80  70  70
Gainesville     64  75  64  73 /  90  90  70  80
Macon           68  77  67  79 /  90  90  70  70
Rome            65  77  62  75 /  90  70  70  70
Peachtree City  66  77  65  76 /  90  80  70  70
Vidalia         71  79  68  79 /  80  80  70  70

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through Wednesday afternoon for the following
zones: Baldwin...Banks...Barrow...Bibb...Bleckley...Butts...
Carroll...Chattahoochee...Cherokee...Clarke...Clayton...Cobb...
Coweta...Crawford...Crisp...DeKalb...Dooly...Douglas...Fayette...
Forsyth...Glascock...Greene...Gwinnett...Hall...Hancock...
Haralson...Harris...Heard...Henry...Houston...Jackson...Jasper...
Jefferson...Jones...Lamar...Macon...Madison...Marion...
Meriwether...Monroe...Morgan...Muscogee...Newton...North
Fulton...Oconee...Oglethorpe...Paulding...Peach...Pike...Polk...
Pulaski...Putnam...Rockdale...Schley...South Fulton...Spalding...
Stewart...Sumter...Talbot...Taliaferro...Taylor...Troup...
Twiggs...Upson...Walton...Warren...Washington...Webster...
Wilkes...Wilkinson.

&&

$$

SHORT TERM...BDL
LONG TERM....Kovacik
AVIATION...BDL



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