Scientific Forecaster Discussion
fxus62 kffc 221137
Area forecast discussion
National Weather Service Peachtree City Georgia
737 am EDT Tue Oct 22 2019
updated for 12z aviation discussion.
Previous discussion... /issued 409 am EDT Tue Oct 22 2019/
Short term /today through Wednesday/...
Current radar this morning is showing a broken line of showers
pushing into northwestern Georgia ahead of a cold front. The front
is currently draped from southwest to northeast across Alabama and
is expected to continue working across the area through the rest of
this morning and into this afternoon. For the immediate short term
period, instability remains fairly limited so there's just a slight
chance for thunderstorms. For this afternoon, as the front is moving
through portions of eastern central Georgia, better instability will
be present so the chances for thunderstorms will continue with the
potential for a strong to isolated severe thunderstorm possible with
gusty winds being the main threat. By later this afternoon, the
front should have cleared through the local forecast area leaving
elevated winds during the day in addition to much cooler
temperatures and drier air filtering in. Winds should remain below
advisory criteria but gusts in the 20-25 mph range will be possible
through the evening. Behind the front at the surface, high pressure
will build into the area keeping US dry for Wednesday.
High temperatures across the area today will be slightly cooler than
yesterday with 60s across much of northern Georgia getting into the
70s across central Georgia. With the passage of the cold front,
overnight lows will be just slightly below average, with 40s area-
wide. High temperatures on Wednesday will also be just slightly
below average, in the 50s across the mountains with 60s across
northern Georgia and lower 70s across the rest of the area.
Long term /Wednesday night through Monday/...
The long term portion begins with high pressure anchored over the
mid Atlantic states with ridging through NE Georgia. This will allow
for continued cool conditions across the area with upper 30s in
the mountains to low to mid 40s along and north of the i20
The high will begin to be squeezed by Thu afternoon as storm
systems approach from both the north and the Gulf. Still dry
conditions however and a moderating airmass with temperatures
reaching the 70s over most locales.
Continued major differences in the long term models for the end of
the week. European model (ecmwf) has a cutoff low just emerging from The Four
Corners states Fri afternoon while the GFS is much more
progressive showing open trough approaching the Mississippi
This means the difference between categorical pops and
near nil pops depending on the model you go with. Will use a blend
favoring the GFS and yielding likely pops for west central Georgia for
Models do get on the same Page by pop wise late Sun night into Mon
morning but for completely different reasons. Given the
uncertainty, will limit pops to mid range chance at best through
early next week.
mixed bag of IFR/MVFR cigs and vsbys across the area will give
way to VFR conditions after the front passes and rain showers clears,
around 13-16z for all taf sites. Gusty winds possible with shra,
around 20-30kts. Surface winds across the atl taf sites are NW,
with mcn/ahn still S. All winds should flip northwest/west-northwest over the next
few of hours. Post fropa winds will become northwest at 10-15kts with
gusts 20-25kts possible. Expecting sky clear at all taf sites after
17-18z today with dry weather expected through the rest of the
//Atl confidence...12z update...
medium to high on all elements.
Preliminary point temps/pops...
Athens 73 45 69 44 / 60 0 0 0
Atlanta 69 45 67 46 / 40 0 0 0
Blairsville 65 39 63 39 / 50 0 0 0
Cartersville 70 41 68 44 / 20 0 0 0
Columbus 74 47 71 48 / 40 0 0 0
Gainesville 69 45 67 44 / 50 0 0 0
Macon 76 47 71 47 / 50 0 0 0
Rome 70 41 69 42 / 20 0 0 0
Peachtree City 71 44 69 44 / 40 0 0 0
Vidalia 79 49 73 51 / 40 5 0 0