Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Memphis Tennessee
521 PM CST Sat Jan 31 2015
Previous discussion... /issued 317 PM CST Sat Jan 31 2015/
A low pressure system with an associated cold front will track
northeast out of the Oklahoma into the Ohio Valley tonight through
Sunday evening. The midsouth is already seeing abundant middle to
high clouds ahead of the system. The clouds have kept temperatures
rather cool today. Cooler than previously thought. Low clouds will
begin to spread into the area after midnight. Models seem a tad
slower with precipitation but still think showers will move into
eastern Arkansas just before sunrise. Temperatures will likely
hold steady or only drop slightly this evening as winds start to
turn around to the south. Expect lows in the middle to upper 40s.
Widespread showers will spread into the midsouth on Sunday and
will continue through much of the day. Could see some rumbles of
thunder south of Interstate 40. Southerly winds ahead of the
approaching front should warm temperatures into the 50s despite
The showers will come to an end quickly from the west Sunday
evening. Could see some flurries on the back side of the cold
front after midnight Sunday night. Lows will be in the upper 20s
to the middle 30s.
Arctic high pressure will settle over the midsouth Monday into
Monday night. Clouds will hang on through much of the day thus
will keep temperatures from warming hardly at all. Expect highs to
be in the 30s. Skies should clear by Monday night allowing lows to
plummet into the upper teens to middle 20s.
Confidence in forecast decrease significantly beyond Wednesday
especially with forecast Wednesday night into Thursday night.
Models have come together at least on Wednesday with a passage of
a cold front. Although they still differ in regards to precipitation. The
European model (ecmwf) remains dry while the GFS continues to show light precipitation
over portions of the area. By Wednesday night into Thursday the
differences between the models are huge. The European model (ecmwf) builds Arctic
high pressure into the area while the GFS swings a shortwave into
the area. The shortwave would produce precipitation over the area.
With Arctic air plunging into the midsouth...rain would change
over to possibly freezing rain then to all snow late Wednesday
night into Thursday. The model indicates that around 2 inches of
snow could fall over much of the County Warning Area by end of the day Thursday.
The snow would quickly push east Thursday night. However...looking
at the GFS ensembles a lot of members are leaning toward the drier
European model (ecmwf). Will this trend continue...who knows. Both the European model (ecmwf) and
the GFS have been consistent with there solutions for the last
three runs. One will eventually change. For now will continue with
20-30 probability of precipitation for rain/snow to represent a blend. However it will
either be dry if the European model (ecmwf) is correct or probability of precipitation will need to be
increased with added mention of winter weather in the severe weather potential statement if the
GFS is correct. For now will leave out of severe weather potential statement due to such low
By end of the week into early next weekend...high pressure will
rebuild into the County Warning Area.
Aviation...00z taf cycle
Definitely not good conditions for flying over the next 24 hours.
Conditions are VFR currently at all sites...but deteriorating
conditions are expected tonight...with IFR conditions prevailing
tomorrow. Expect ceilings to lower to IFR by middle morning...01/14z-01/17z.
Light southeast winds will veer southerly overnight...increase and
become gusty Sunday morning. Sustained speeds should be 10-15kt
with gusts to 20kts. Further veering is expected tomorrow
afternoon when southwest winds are expected. Visible will be MVFR for
most of the day tomorrow due to rain. Although thunderstorms
cannot be ruled out...do not feel they will be numerous to include
in tafs at this time.