Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Peachtree City Georgia
123 PM EDT Monday Apr 27 2015
Previous discussion... /issued 1015 am EDT Monday Apr 27 2015/
Will just be updating the diurnal curve this morning which was
thrown off slightly by low clouds across the area which have since
dissipated. Otherwise...forecast grids in good shape on this fine
Spring day and no changes are planned.
Previous discussion... /issued 729 am EDT Monday Apr 27 2015/
Previous discussion... /issued 326 am EDT Monday Apr 27 2015/
Short term /today through Tuesday/...
old frontal boundary will continue to push southward today as high
pressure builds in from the north. Conditions are expected to remain
dry with partly to mostly sunny skies.
Clouds begin to increase overnight as low pressure system currently
across southern Texas emerges into the northern Gulf and moves
eastward. By Tuesday...this low pressure system begins to push east
along the Gulf Coast...bringing the next round of precipitation.
Rain chances really begin to increase in the west and southwest
during the day on Tuesday. Very little instability with this
system...so have only added a slight chance of thunder for Tuesday
afternoon. With all of the cloud cover and showers...temperatures are
expected to be around 5 to 7 degrees below normal for this time of
Most of the quantitative precipitation forecast for this system is currently expected to fall just
outside of the short term portion of the forecast. Up to three
quarters of an inch of rain is possible in the far SW on Tuesday.
Long term /Tuesday night through Sunday/...
still one main system to focus on for the long term. Closed upper
level low slides from the Mississippi Valley into the Tennessee
Valley Tuesday night while the surface low slides along the Gulf
Coast. This should result in rain spreading across the County Warning Area at the
beginning of the long term and Tuesday night and Wednesday still
look to be the most likely time period for precipitation. As the
surface low tracks into the Atlantic...rain should end by Friday.
There still remain some differences in how the European model (ecmwf) and the GFS
are resolving features with this system /especially in terms of
the surface low track once it moves into that Atlantic and the upper
level shortwave as it tracks across the east/ but the majority of
the time the two models are in decent agreement on the weather
impacts for the County Warning Area. Instability values are a little bit higher
than have been noted in previous runs with MUCAPE values exceeding
1000 j/kg on Wednesday afternoon. In addition...the higher values
spread further northward. With this forecast have included than
mention of thunderstorms further northward /into the southern and
western portions of the atl metropolitan area/ compared to the previous
High pressure builds in for the weekend...allowing for dry
conditions across the County Warning Area.
MVFR has lifted across all taf sites which were impacted and
anticipate VFR conditions for the remainder of this taf period.
Increasing chances for -ra for the end of the taf
period...especially for csg but should still be VFR. Keeping wind
shift at atl as is at around 05z.
//Atl confidence...18z update...
high on all elements.
Preliminary point temps/pops...
Athens 73 50 70 51 / 5 5 40 70
Atlanta 72 52 68 52 / 0 5 60 70
Blairsville 66 42 66 47 / 0 5 50 70
Cartersville 70 47 69 51 / 0 5 60 80
Columbus 77 57 70 56 / 0 20 70 70
Gainesville 71 50 67 51 / 0 5 50 70
Macon 75 54 70 54 / 0 5 60 70
Rome 70 47 69 51 / 0 5 60 70
Peachtree City 73 50 68 52 / 0 5 60 80
Vidalia 76 58 71 58 / 5 5 50 70