Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Peachtree City Georgia
1030 PM EDT Thursday Jul 24 2014
no changes planned for the forecast. Line of convection has
diminished but isolated storms possible for much of the night mainly
across central areas. More stable air should gradually work its way
into north Georgia overnight.
short term /tonight through Friday night/...
upper trough axis is stretched down the Appalachians this
afternoon...prognosticated to shift east and damp through the short term.
Attendant cold front is working its way into north Georgia at afd
time. The cold front is not particularly cold and is more of a
dewpoint gradient as there is very little temperature advection on
either side of the front. Pre-frontal convection is increasing
developing across the area...hrrr has had a very good handle on this
all day but 12z runs of other hires guidance have caught up...with
all showing convection lingering across the metropolitan area until after
00z. Not really expecting anything severe but with dcape values
approaching 1000 j/kg across north Georgia cannot rule out a few
strong storms. With loss of heating and reduction in SBCAPE
values...storms should begin to break up thereafter.
The front slides south into the metropolitan area overnight but plenty of
surface moisture along and ahead of the front will lead to patchy
fog in the morning...especially at climatologically fog-prone areas.
Front stalls across the area tonight and Friday as vorticity
advection decreases and flow aloft weakens. Probability of precipitation increase again
tomorrow but have kept probability of precipitation generally south of a Carrollton to
Atlanta to Athens line...with best chances south of Columbus to
Macon to Louisville. Afternoon high temperatures continue just
slightly below normal for this time of year especially up in north
Georgia behind the front.
Long term /Saturday through Thursday/...
only minor adjustments made as forecast is largely on track. Previous
Long term /Friday night through Wednesday/...
/issued at 456 am EDT Thursday Jul 24 2014/
models continue to show a few upper level disturbances to
traverse the region over the weekend. Surface high should keep
probability of precipitation to a minimum Saturday...and with front approaching the area
Sunday...high will lose control of the area and allow for
increasing rain chances. Extended periods are still largely
dominated by this strong cold front /anomalous for late July/ and
models agree with pushing it through north and central Georgia by
late Monday. Deep longwave trough remains positioned over the area
through much of next week...keeping lower dew points and cooler
temperatures in place in the wake of the cold front. Some moisture
does look to creep back northward as boundary remains over south
Georgia...and have generally included slight chance probability of precipitation in the far
southern portions of the County Warning Area through Wednesday. Beginning
Tuesday...should see below average temperatures with highs in the
upper 70s north and low 80s elsewhere...and lows in the 60s.
Strong to severe storms may accompany the front as it pushes
through the area Monday with models continuing to advertise a
combination of decent shear and instability. With some uncertainty
in the forecast models regarding the timing of this system...the
severe potential will need to continue to be monitored.
line of convection slowly moving southward into central Georgia. If it
holds together...csg and mcn may be affected before midnight. Should
be mainly middle/high clouds much of tonight but some sct030/040 may
linger. Have added IFR ceilings across the metropolitan atl taf sites due
to rainfall received during the afternoon. Some MVFR visibility
possible elsewhere. Winds generally west to northwest through the
period with some gusts near storms.
//Atl confidence...00z update...
medium to high on all elements.
Preliminary point temps/pops...
Athens 70 91 70 93 / 30 10 5 5
Atlanta 71 87 72 90 / 30 10 5 5
Blairsville 62 84 60 86 / 20 10 5 10
Cartersville 68 88 69 91 / 20 5 5 5
Columbus 73 89 73 92 / 30 30 5 10
Gainesville 70 87 70 89 / 30 10 5 10
Macon 70 89 71 91 / 30 30 10 10
Rome 68 89 68 92 / 20 5 0 5
Peachtree City 69 88 69 91 / 40 20 5 5
Vidalia 73 92 73 93 / 30 30 20 20