Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Memphis Tennessee
508 am CST Friday Jan 30 2015
Aviation discussion updated below for 12z taf set...
Previous discussion... /issued 438 am CST Friday Jan 30 2015/
For today...precipitation free weather will occur with high
temperatures a little below normal. High pressure will move from
the upper Midwest to the Ohio River valley and extend into the
midsouth. Light to moderate northeast winds will occur. Models
indicate that low clouds from west Tennessee into portions of northeast
MS will quickly clear this morning.
Surface high pressure will move to the southern Appalachians tonight
as an upper level ridge strengthens to our west. High level clouds
will gradually increase from the west. With a light wind...it will
be cold with low temperatures dropping into the 20s.
Dry weather will persist into the day Saturday with cool high
pressure continuing to dominate our weather. Temperatures will be a
little warmer in the afternoon as winds turn to the southeast.
A change in the weather will occur Saturday night as a warm front
approaches from the southwest and a northern stream upper level short
wave approaches from the northwest. Divided the pop group into two
six hour periods...since looks like most of the rain will hold off
until after midnight. A chance of rain will spread into northeast Arkansas
and the MO bootheel before midnight...then rain will quickly
become more widespread from the west after midnight.
Sunday looks to be wet for the entire region. A cold front
followed by much colder air will push into the area as surface low
pressure strengthens and moves into Kentucky by sunset. Showers look to
be widespread Sunday. The NAM is indicating enough elevated
instability for a few thunderstorms. However...the GFS and European model (ecmwf)
are keeping it more stable. For now...held off mentioning any
thunder in the forecast...but will keep an eye on this potential.
Windy and much colder air will sweep into the midsouth Sunday night
as the cold front moves to the east. Wind chill readings will
drop to between 10 and 20 degrees overnight. Looks like the
precipitation will mostly end or taper off about the time it become
cold enough for the rain to turn to snow. Nevertheless...may see some
light snow or flurries as a trailing upper level short wave interacts
with the cold air. Looks like the best possibility of minor snow
accumulations Sunday night would be along and east of a line from
Union City Tennessee to Jackson Tennessee to around Iuka Mississippi.
Right now...it does not look like much.
Cold air will settle over the midsouth Monday with skies gradually
clearing. High temperatures will only be in the 30s. Wind chill
readings Monday morning will remain between 10 and 20 degrees. The
cold high pressure system will move to the east Tuesday with winds
turning to the south causing temperatures to warm into the
40s during the afternoon. A southern stream short wave is forecast
to move to our south Tuesday night into Wednesday with surface low
pressure developing over the northern Gulf. Rain associated with
this system is forecast to mainly affect east central Arkansas and north
MS. Looks like the low will move to the east with precipitation ending
before it will be cold enough for any wintry precipitation...but will keep
an eye on this also. Another cold front followed by much colder
air will push through the region Thursday. There are some indications
that we could see a few flurries with this front...but confidence is
not high enough to mention in the forecast at this time.
12z taf cycle
North-northwest flow and moisture near the 3500 feet layer have
maintained a cloud deck through the night at all terminals except
jbr. Mem is very near the western edge but believe they will
remain clear. Sites should remain VFR through the period with
skies clearing at all taf sites after 21z on Friday. Winds will
briefly increase this morning to near or just above 10 kts from
the north before gradually tapering off by 00z Saturday.