Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Peachtree City Georgia
1050 am EDT sun Apr 26 2015
no changes planned for the forecast.
Previous discussion... /issued 322 am EDT sun Apr 26 2015/
Short term /today through Monday/...
an old frontal boundary is currently situated near the Georgia/Tennessee border.
Several waves of low pressure will move east along the boundary.
Regional radar shows a line of showers and a few thunderstorms
closing in on the Georgia/Tennessee state line and sinking southward.
Overall...the trend has been for this line of showers to weaken.
However...a strong storm or two is possible and an occasional
lightning strike is likely. Even showers will have the potential to
be gusty with the strong winds just above the surface.
Hi-res models continue to show this line weakening through the early
morning hours. However...not confident the line will completely
diminish. The hi-res models don't seem to have a great handle on the
system. Have adjusted probability of precipitation slightly upwards across northern Georgia to
reflect current trends.
With the boundary moving southward today...am hesitant to remove all
probability of precipitation. Especially with the hi-res models not resolving the current
system well. The boundary should clear the County warning forecast area late this
afternoon/evening and the remainder of the short term forecast
should be dry and seasonable.
Even though instability will be marginal...shear across the area
remains pretty high. Even though the coverage of storms should be
isolated this afternoon...a strong thunderstorm or even a severe
thunderstorm will still be possible.
Long term /Monday night through Saturday/...
only one weather system to focus on in the extended. A shortwave
slides across the Tennessee Valley middle week while the surface low tracks along
the Gulf states and across southern Georgia. Although this will
bring bring showers and thunderstorms back to the County Warning Area Tuesday
through Thursday...instability with the system is limited /generally
less than 500 j/kg of MUCAPE/ which will result in mostly showers
for north Georgia and isolated thunderstorms with the showers across
central Georgia where this higher instability is located. Still some
minor differences between the GFS and European model (ecmwf) in terms of features and
timing...but both are in agreement that the best chances for
precipitation will be in the Tuesday night to Wednesday time frame.
After this system moves through...high pressure dominates at the surface
and keeps the County Warning Area dry through the weekend.
earlier showers have dissipated across northern Georgia. A cold front
will move south across the region today. Some patchy IFR ceilings
remain this morning...but should break by the late morning hours.
After then...VFR conditions through the period. West winds will
gust to 20-25mph today. Winds should shift to the northwest by the
//Atl confidence...12z update...
medium confidence ceilings. High confidence remaining elements.
Preliminary point temps/pops...
Athens 81 54 73 49 / 20 10 0 5
Atlanta 80 54 72 51 / 20 5 0 5
Blairsville 71 44 65 42 / 20 10 0 5
Cartersville 77 49 69 47 / 20 0 0 5
Columbus 85 58 76 55 / 20 5 0 5
Gainesville 76 52 70 49 / 20 10 0 5
Macon 85 56 75 52 / 20 10 0 5
Rome 77 49 69 47 / 20 0 0 5
Peachtree City 82 52 74 49 / 20 5 0 5
Vidalia 86 61 75 57 / 20 10 0 5