Area forecast discussion
National Weather Service Peachtree City Georgia
357 am EDT sun may 19 2013
Short term /today through Monday/...
500mb analysis shows an upper low across southern Kentucky with a
shortwave trough extending into northern Georgia. This feature has helped
develop and sustain convection across northern portions of the County warning forecast area
early this morning. Abundant moisture and light boundary layer winds
have combined to produce slow moving heavy rainers. Mpe places an
axis of heavy rain from southeast Walker County into eastern Dawson
County. The more widespread activity is slowly pushing off to the
east...but convection continues to develop back off to the west. Do
think the primary threat from thunderstorms this morning will
continue to be locally heavy rainfall.
Forecast challenge in this weather pattern is where convection will
develop. For the northern and central County warning forecast area...the hrrr seems to have
the best handle on the current convective trends. This has been the
case for the last several days. Have modeled probability of precipitation around the hrrr
output for much of the first period. Do expect additional storms to
keep firing across northwest Georgia this morning and spreading southeast. The
synoptic models are still hinting at a mesoscale convective system type feature developing
across the central County warning forecast area and pushing southeast today. The hrrr actually is
hinting at this also. Not very confident this will
happen...especially with all of the cloud debris around. More
scattered activity could develop along the southern tier of
zones...where they have the best chance of seeing the most heating.
If an mesoscale convective system feature does develop...any severe thunderstorms that
develop will have the potential to produce wet microbursts. Flash
flooding will also be a hazard...especially where storms repeatedly
move.
Took blend for temperatures.
Long term /Monday night through Saturday/...
Preicp should end from west to east tonight as the shortwave trough
sets up along the eastern Seaboard. Have only tweaked probability of precipitation during
this period.
For the first part of the week...the 500mb trough/shear axis remains
across the southeast coast. This feature will help focus scattered diurnal
convection each day. Previous runs pushed the feature off the coast
on Tuesday...but it should remain in place until early Wednesday.
For the latter part of the week...a cold front is expected to move
into the southeast states. Model run to run consistency for this
feature has been low for the past few days. The European model (ecmwf) now has the
boundary approaching northern Georgia on Friday...and moving through the
County warning forecast area during the day. The GFS has continues to bring the boundary
southward. Neither model is producing much precipitation with this feature
for now...so will leave probability of precipitation in the scattered range.
High pressure returns for next weekend.
Main changes to the extended were to up probability of precipitation slightly in the east
for Wednesday. Mainly persistence for the latter half of week.
&&
Aviation...
06z update...
current pattern makes it difficult to forecast the timing of
convection. Followed the latest run of the hrrr fairly closely for
convective elements...over the last few days...it has been the
best model. Ceilings and winds will also be a challenge. Models do
have ceiling values dipping to IFR and observation reflect this...also areas
of fog will be present but only have 5-6sm previous. Morning
convection may limit afternoon development.
//Atl confidence...06z update...
low confidence on ceilings and timing of shra/tsra. Medium confidence
remainder of elements.
&&
Preliminary point temps/pops...
Athens 79 64 85 66 / 60 50 30 20
Atlanta 80 66 86 66 / 60 30 20 10
Blairsville 73 59 83 60 / 70 50 30 20
Cartersville 80 65 88 65 / 60 30 20 20
Columbus 86 67 90 67 / 40 30 20 10
Gainesville 77 63 85 65 / 70 50 30 20
Macon 85 66 88 66 / 50 30 30 10
Rome 81 65 89 65 / 60 30 20 20
Peachtree City 81 64 87 64 / 50 30 20 10
Vidalia 84 67 83 66 / 50 50 40 20
&&
Ffc watches/warnings/advisories...
none.
&&
$$
Short term...nlistemaa
long term....nlistemaa
aviation...nlistemaa
