Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Peachtree City Georgia
1045 am EST Sat Feb 6 2016
No changes planned for the forecast.
Previous discussion... /issued 416 am EST Sat Feb 6 2016/
Short term /today through Sunday/...
high pressure will continue at the surface today. The high pressure
system will break down early this evening and overnight as a low
pressure wave forms to the south. Meanwhile...at 500mb...an upper
low/trough will move into the lower Mississippi River valley today
and then across the southeast states overnight and early Sunday.
There are some pretty big differences in the models overnight into
early Sunday morning...but the NAM is a pretty big outlier. The NAM
is wetter and has its low pressure center further to the north and
west than the other models. The GFS and European model (ecmwf) are very similar with
the low pressure placement...but the European model (ecmwf) is slightly wetter than
the GFS. Have pretty much discarded the NAM solution...and taken a
compromise between the GFS and the European model (ecmwf) for Saturday night/early
All of the model soundings indicate that the atmos will be cold
enough for snow aloft. However...there is a layer of warm air near
the surface. The GFS and European model (ecmwf) have a deeper layer of warmer air
near the surface than the NAM...but all of the models are showing
some potential for the ptype to be a rasn mix. A big however...the
probability of precipitation are going to be fairly low across the County warning forecast area...with the highest
values across far eastern Georgia and South Carolina. Have bumped
values up a bit in the far eastern County warning forecast area to account for the European model (ecmwf)
vs the blend numbers.
Long term /Sunday night through Friday/...
no significant changes to the extended forecast trends with this
cycle. Medium range models remain consistent through the period with
a cold start and a moderating second half of the week. Wintry
weather still looks likely across north Georgia from early Monday
through early Wednesday. Best forcing and moisture remains in the
Monday/Monday night period as temperatures fall. Should see
precipitation start as mostly rain early Monday before the more
significant push of colder air. Some rain/snow mixture is likely in
the higher elevations from onset. By late in the day Monday through
the evening...cold airmass coincides with the tail end of the better
forcing and moisture with limited moisture and mainly cold
advection/orographic influences by daytime Tuesday through Tuesday
night limiting overall snow totals. Still looks like we will see a
dusting to a half inch from the Atlanta metropolitan area northward with 1-
2 inches in the mountains...especially north through west facing
slopes. Highest ridgetops could see higher totals. Moisture becomes
too scarce for any mention of precipitation after Tuesday night...
but a few flurries are not impossible in the far northern mountains
into the daytime Wednesday.
Temperatures begin moderating by Thursday as the upper-level flow Delaware-
amplifies with near seasonal temperatures by Friday and Saturday.
VFR ceilings/visibilities through the period...with some passing cirrus. East
winds today will switch to the northwest overnight and continue through
Sunday. A few gusts around 20 knots are possible during the day on
//Atl confidence...12z update...
high confidence all elements.
Preliminary point temps/pops...
Athens 52 30 56 36 / 0 0 5 5
Atlanta 52 32 54 38 / 0 0 5 5
Blairsville 48 27 51 32 / 0 0 5 20
Cartersville 52 29 54 36 / 0 0 5 10
Columbus 55 32 56 37 / 0 0 5 5
Gainesville 50 32 53 36 / 0 0 5 10
Macon 54 31 56 36 / 5 5 5 5
Rome 52 29 55 35 / 0 0 5 20
Peachtree City 53 29 55 36 / 0 0 5 5
Vidalia 53 36 55 38 / 20 30 20 5