Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Peachtree City Georgia
253 PM EDT Sat Jul 4 2015

Short term /tonight through Sunday night/...
early morning convection across portions of northern Georgia has led
to a somewhat stabilized airmass across the metropolitan area this
afternoon. Clearing has occurred and temperatures are rising into the 80s.
Further south...outflow boundary from the morning convection is
interacting with ongoing storms. The atmosphere will be conducive
for a few strong storms...with an isolated severe storm possible.
Damaging wind gusts would be the primary severe weather threat.

For tonight...next wave of convection is getting fired up across
eastern MS and western Alabama. The hrrr and the WRF show this cluster of
storms approaching the Alabama/Georgia state line around 00z. Both the hi-res
models weaken the activity as it crosses the state line...but the
WRF has less coverage than the hrrr. Neither model had a great
handle on this mornings convection...until a few hours into it.
Since this would be the timing that the upper low and a large area
of upper diffluence crosses the County warning forecast area...have kept the probability of precipitation likely
mainly along and west of Interstate 85. The models do forecast precipitation
diminishing after 06z. This seems reasonable so have decreased the
probability of precipitation between 06z and 12z.

The pattern does not change for Sunday...so expect additional
showers and storms. Think the best timing for storms should be in
the afternoon.

Nlistemaa



Long term /Monday through Saturday/...
mainly only tweaks to the long term based on the lastest
guidance.

Bdl

Previous discussion...
by Monday...upper level trough axis is over the eastern two thirds
of the area with some middle level drier air noted for the northern
County Warning Area with precipitable water dropping to 1.4 inches. Overall would
expect this to result in a reduction in coverage of storms over
previous days and plan to continue lowering probability of precipitation through the end
of the forecast. Drier air continues for Tuesday before eroding
away and giving way to a bit of increased moisture for the
remainder of the long term. With middle and upper level ridge
building in however...upper level energy is much reduced through
the period and diurnally favored chance probability of precipitation look suffice for the
grids. Remainder of the forecast is on track and no major changes
are planned.

Deese/01

&&

Aviation...
18z update...
a lull in convection is expected for the next 3 to 4 hours across
northern Georgia. Hi-res models are increasing the coverage of storms
again after 00z as another wave moves east in the flow. Winds will
remain on the west side. MVFR ceilings and patchy fog are possible
after 06z...especially in those areas that received rainfall.

//Atl confidence...18z update...
medium confidence all elements.

&&

Preliminary point temps/pops...
Athens 69 84 69 86 / 50 60 40 50
Atlanta 70 81 69 84 / 60 60 40 50
Blairsville 63 76 63 79 / 60 60 50 50
Cartersville 68 80 68 84 / 70 60 40 50
Columbus 72 85 71 87 / 60 60 40 50
Gainesville 68 80 68 83 / 60 60 50 50
Macon 71 88 70 88 / 30 60 40 50
Rome 68 81 68 85 / 70 60 40 50
Peachtree City 69 82 69 85 / 60 60 40 50
Vidalia 73 92 72 89 / 30 60 40 50

&&

Ffc watches/warnings/advisories...
Flash Flood Watch through Sunday evening for the following
zones: banks...Barrow...Bartow...Carroll...Catoosa...Chattooga...
Cherokee...Clarke...Clayton...Cobb...Coweta...Dade...Dawson...
DeKalb...Douglas...Fannin...Fayette...Floyd...Forsyth...Gilmer...
Gordon...Gwinnett...Hall...Haralson...heard...Henry...Jackson...
Lumpkin...Madison...Murray...Newton...north Fulton...Oconee...
Oglethorpe...Paulding...Pickens...Polk...Rockdale...South
Fulton...towns...Union...Walker...Walton...white...Whitfield...
Wilkes.

&&

$$

Short term...nlistemaa
long term....bdl
aviation...nlistemaa

National Weather Service Glossary of Abbreviations