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Area Forecast Discussion (AFD)

Issued by Peachtree City, GA (FFC)

                            
000
FXUS62 KFFC 211933
AFDFFC

Area Forecast Discussion
National Weather Service Peachtree City GA
233 PM EST Thu Feb 21 2019

.SHORT TERM /Tonight through Friday Night/...
Expecting scattered convection and isolated thunder to increase in 
coverage this afternoon into evening as isentropic upglide along and 
north of a warm front pushes northward across the area. See 
Hydrology section below for an update on expected rainfall and flood 
products. 

Otherwise higher pops for showers should focus back to north GA 
later tonight through Friday. Given how some dense fog persisted 
this morning and how guidance is indicating the southern majority of 
the area could tank again tonight (even SREF vsby probs for less 
than 1 mile are pretty high), have added wording of areas of dense 
fog to the forecast and the evening or overnight updates may warrant 
an advisory if it continues to look favorable. 

Despite the warm front lifting north in the first part of the short 
term, a CAD wedge looks to build back into the area by later Friday 
afternoon. While models indicate some elevated instability possible, 
the current thinking is that the wedge and persistent cloud cover 
will keep the environment mostly stable and have left thunder 
mention out with just showers. Highs may be limited to the mid to 
upper 50s in the northeast with a rather tight gradient of higher 
temps farther west and south. Central Georgia still could be as warm 
as the mid to upper 70s - possibly near the 80 mark in the far
south.

Baker


.LONG TERM /Saturday through Thursday/...
Not too many changes from forecast early this morning...see
forecast discussion below. Models showing surface front will push
into northwest Georgia during the early morning hours on Sunday,
move through Atlanta by midday, and exit the forecast area by
Sunday evening. The wave that develops over the northern Gulf on
Tuesday/Wednesday remains a bit further south than expected and
have adjusted POPs across the area accordingly. Extended period
temperatures continue to show near normal highs with warmer than
normal lows most days, except Monday morning when lows will be
near normal.

Atwell
PREV DISCUSSION... /Issued 338 AM EST Thu Feb 21 2019/ 
The long term period begins with a wedge setting in to NE Georgia
in addition to a stalled front just north of the area. With 
southwesterly flow pushing moisture into the area, chances for 
showers will continue through Saturday, with the highest chances 
across northern Georgia. High PWs and instability will continue 
the potential for periods of heavy rain and isolated thunderstorms
across the area. With multiple rivers across northern Georgia 
already in flood, concerns for river flooding and flash flooding 
will continue as these rounds of precipitation impact the area, 
especially across portions of northern Georgia. 

Chances for showers and thunderstorms increase across the entire 
area for late Saturday/Sunday as a cold front pushes through the 
area on Sunday. QPF totals are currently around half and inch to
an inch with the highest totals across northern GA. With already
saturated soils across much of northern Georgia concerns for river
flooding and flash flooding will continue. After this system 
clears the area late Sunday, we should see some drier weather on 
Monday and for some areas part of Tuesday as high pressure pushes
into the area. Models then show a wave moving north from the gulf
into the area on late Tuesday into Wednesday, but models differ 
on northward extent as well timing of the moisture across the 
area. At this point have only included slight chance pops across 
the area. 

Temperatures through the weekend are expected to be just above 
average in the 60s and 70s, aside from those within the wedge on 
Saturday where highs are expected to be in the 50s. After the 
weekend system, high temperatures are expected to be closer to 
seasonal norms.

Reaves


&&

.HYDROLOGY...
Given how some storms and heavy showers could train across the 
southern extent of the current Flash Flood Watch (close to the I-85 
corridor), we have opted to maintain the watch through 00z this 
evening. As the forcing and main moisture axis focuses back to 
portions of north Ga overnight and Friday, an additional 1-2 
inches of QPF is possible and therefore have issued a Flood Watch 
along and north of a Rome to Canton to Cleveland line from 00z 
tonight through 00z Saturday.


&&

.PREV DISCUSSION... /Issued 115 PM EST Thu Feb 21 2019/ 

AVIATION...
18Z Update...
Mainly LIFR cigs lingering across the sites (scattered higher near
KCSG), and KATL has been holding close to 300 ft. LIFR/VLIFR 
vsbys with fog in the north should improve to MVFR or VFR this 
afternoon as a warm front lifts northward. Shower and TS chances 
increase after 19/20z this afternoon then focus shifting to the 
northern sites later. There is a good chance some dense fog will 
return to the sites early Friday morning so have 1/4SM with again 
LIFR cigs from 09z to 15z. Winds initially light VRB for most 
sites (could stay light east for KATL) then light NE to SE
overnight.

//ATL Confidence...18Z Update...
Medium on TS and SHRA coverage/timing this afternoon/evening.
Medium on extent of possible dense fog Friday AM.
High on all else.

Baker

&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          54  58  47  59 /  70  60  50  40 
Atlanta         56  63  50  64 /  70  50  50  40 
Blairsville     52  56  47  58 /  80  80  70  50 
Cartersville    52  62  50  64 /  60  60  60  40 
Columbus        63  76  59  77 /  50  30  30  30 
Gainesville     54  56  46  57 /  70  70  60  50 
Macon           60  74  56  73 /  40  30  40  30 
Rome            51  60  51  65 /  60  80  70  50 
Peachtree City  56  67  52  68 /  70  40  40  40 
Vidalia         62  79  60  74 /  40  30  40  30 

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch until 7 PM EST this evening for the following 
zones: Banks...Barrow...Bartow...Carroll...Catoosa...Chattooga...
Cherokee...Clayton...Cobb...Coweta...Dade...Dawson...DeKalb...
Douglas...Fannin...Fayette...Floyd...Forsyth...Gilmer...Gordon...
Gwinnett...Hall...Haralson...Heard...Jackson...Lumpkin...
Murray...North Fulton...Paulding...Pickens...Polk...South 
Fulton...Towns...Union...Walker...White...Whitfield.

&&

$$

SHORT TERM...Baker
LONG TERM....Atwell
AVIATION...Baker