Scientific Forecaster Discussion
fxus62 kffc 262353
Area forecast discussion
National Weather Service Peachtree City Georgia
753 PM EDT Fri may 26 2017
Previous discussion... /issued 331 PM EDT Fri may 26 2017/
Short term /tonight through Saturday night/...
High pressure over the region will shift southeast into Saturday.
Have continued with slight chance to chance pops across far north
Georgia late Saturday afternoon as models continue to advertise
a frontal boundary settling over the Tennessee Valley, with
convection firing along it. At this time, modeled surface
instabilities, steep lapse rates and deep layer shear could result
in strong to severe storms. That being said, at least for now,
coverage of these stronger storms should be low, with some hi-res
solutions not even advertising any of the thunderstorm activity
working its way into the state. Have continued with a forecast
compromise with a blend of the models. For any strong storms that
develop/move over the area, expect the main hazards to be gusty
winds and hail.
Long term /Sunday through Friday/...
no major changes were made to the long-term forecast. Main focus
continues to be increasing potential for convection by late Sunday
into Monday. Refer to the previous long-term discussion below for
/issued 406 am EDT Fri may 26 2017/
Primary concern in the long term period is deep convection
associated with baroclinic zone forecast to sag into the state
late Sunday and Monday.
00z medium range guidance in fair agreement that front will slip
in Monday and that lift and resulting rainfall will be less than
what we have seen with last few systems this month. Overall
pattern favorable for strong/severe storms in swly flow aloft on
periphery of upper ridge which extends from Texas to Ohio/Tennessee valleys
thru Monday. Georgia appears to be mostly dry, dominated by upper
ridging thru late Sunday, though far northern areas could see a
few storms slip in, especially if a large mesoscale convective system could develop in Tennessee
and propagate southeast. Instability should be sufficient for
strong/severe storms, should any make it into the state, however
vertical wind shear will be weak, especially as you go further
south away from stronger westerlies along periphery of ridge.
Front finally pushes through Monday night/Tuesday but with no
well defined short wave, not much lift will accompany its passage.
As front stalls over far south GA, should see mostly dry weather
until Wed night or Thursday when warm advection ahead of weak,
nearly stalled southern stream wave over Texas and lower MS valley
brings moisture back. Total rainfall Sunday-Tuesday likely to be
0.5 to 1 inch in north Georgia and less than 0.5 inch elsewhere.
VFR conditions to be maintained this forecast despite a few models
showing some MVFR potential Sat afternoon. This seems a stretch
but do anticipate thunderstorms and rain to the north to bring bkn050 down to the
atl terminals. Did not include vcsh at this time to terminal but
may be needed with next forecast. Also added some low end wind
//Atl confidence...00z update...
medium on Sat cig potential.
High on remaining elements.
Preliminary point temps/pops...
Athens 64 88 69 89 / 0 10 10 20
Atlanta 65 87 71 87 / 0 5 10 10
Blairsville 60 82 63 82 / 5 30 30 40
Cartersville 63 86 69 88 / 0 10 20 20
Columbus 64 89 71 90 / 0 5 10 10
Gainesville 65 85 69 86 / 0 10 20 20
Macon 62 90 68 91 / 0 5 10 10
Rome 63 85 68 87 / 0 20 30 30
Peachtree City 61 87 68 88 / 0 5 10 10
Vidalia 64 91 70 94 / 0 5 5 5