Scientific Forecaster Discussion
fxus62 kffc 141847
Area forecast discussion
National Weather Service Peachtree City Georgia
247 PM EDT Mon Oct 14 2019
Short term /tonight through Tuesday night/...
A beautiful fall afternoon across north and central Georgia with
just some passing mid and high clouds. Temperatures have warmed
nicely into the 70s and lower 80s. Hope everyone is getting out to
enjoy today because tomorrow will be a different story.
For the first time in a long while, there's a very good chance for
significant/widespread rainfall across the area Tuesday into Tuesday
evening. The combination of deep lyr moisture and mid lvl energy
overtop a very pronounced low lvl boundary (sfc-850mb) will support
widespread rain across the area beginning early Tuesday morning, and
lasting throughout the much of the day and into the evening hours
before the bulk of the energy and moisture shifts east of the area.
Questions remain about where the heaviest rainfall will occur, and
this will be largely dependent on the orientation/positioning of
that low lvl boundary. At this point, it appears to set up along a
Columbus to Eastman line across our far southern area with the
heaviest rain likely to occur along and just north of this boundary.
Of course, a slight shift north or south will impact the latest
expected rainfall amounts. Feeling pretty good that a swath of 1 to
2 inches will occur across much of middle GA, mainly along and south
of I-20, with locally higher amounts certainly possible between
Columbus and Macon where better moisture and forcing will exist.
Thunderstorm potential remains low at this time as best sfc-based
instability and lapse rates remain south of the area, over South Alabama
and Georgia. That said, cannot rule out a few "elevated" lightning
strikes/storms given strong forcing within proximity of low lvl
boundary and upr lvl shortwave energy.
Contributing to the heavy rain potential for Tuesday are very high
precipitable water (pwat) values, expected to be 1.5 to 1.75" around
the ffc/atl area (closer to 2" around Columbus and macon). These
values would exceed the 90th percentile for Oct 15.
Long term /Wednesday through Monday/...
Overall, made minimal changes through the extended forecast as the
medium range models remain in fairly good agreement through the
majority of the period. Cold front exiting the forecast area
Wednesday to start the period ushering in the coolest air so far
this season. Temperatures at or below seasonal normals for the
latter half of the upcoming workweek, moderating back to at or
slightly above normal through the upcoming weekend and into the
beginning of next week. Dry after the system passes on Wednesday
with moisture and precipitation chances creeping back in by the
weekend and increasing into early next week.
aside from some mid and high lvl clouds, VFR conditions will
prevail across the area through the evening. Later tonight and
into Tuesday, lower clouds and rain showers will overspread the
area from SW to NE with MVFR conditions expected between 12-16z.
As more organized heavier precip moves in throughout the day,
expect IFR cigs and vsby to become more of a factor, initially at
kcsg then spreading North/East, affecting katl btwn 16-18z.
//Atl confidence...18z update...
medium with timing of rain and lower MVFR-IFR ceilings.
High all other elements.
Preliminary point temps/pops...
Athens 56 69 60 76 / 10 80 90 20
Atlanta 60 67 63 73 / 20 90 90 20
Blairsville 49 65 55 65 / 5 70 70 20
Cartersville 55 69 60 72 / 10 80 80 20
Columbus 65 72 66 78 / 60 90 90 30
Gainesville 55 67 60 73 / 10 80 80 20
Macon 63 71 64 78 / 40 90 90 30
Rome 54 70 60 72 / 10 70 80 20
Peachtree City 60 68 62 75 / 20 90 90 20
Vidalia 67 74 68 81 / 30 80 80 50