Scientific Forecaster Discussion
fxus64 kmeg 071752 aaa
Area forecast discussion...updated
National Weather Service Memphis Tennessee
1152 am CST Sat Dec 7 2019
updated for 18z aviation forecast discussion below.
Previous discussion... /issued 521 am CST Sat Dec 7 2019/
Updated for the 12z aviation discussion
Previous discussion... /issued 407 am CST Sat Dec 7 2019/
clouds over much of the mid-south early this morning, expect them
to linger much of the day even as high pressure builds into area.
Some areas will see a little sun, however, these areas will likely
fill back in with clouds.
Models in okay agreement with the rest of the forecast. There are
some timing differences on the next front that moves through on
Monday night through Tuesday.
The pattern over the mid-south the next week is for the upper
levels starting out with some northwest flow, however, it will
change later today to more zonal flow. On Monday an upper level
trough digs in over The Rockies and provides the mid-south with
some southwest flow aloft. This upper trough finally moves through
the area by Wednesday morning. As the trough moves east there will
be zonal flow until late Thursday when an upper level trough digs
into the plain states and provides southwest flow aloft until the
end of the week.
At the surface high pressure builds in for the rest of the
weekend. A low pressure system will move through late Monday. Yet
parts of the mid-south has a chance of rain from Sunday night
through Tuesday night. On Sunday night the rain is more likely to
the north where the warm front should be located, however, upslope
flow may be able to produce some light rain further to the south,
so placed some low pops in much of the forecast area. As the front
approaches on Monday rain showers are more likely everywhere.
The models continue to show the southwest flow aloft on Monday
night into Tuesday will bring enough moisture into the area that
showers will continue through Tuesday evening.
Late on Tuesday a cold high pressure system begins to build into
the area and will bring some cold temperatures for the middle of
the week. Temperatures on Wednesday will stay in the 40s. The
coldest night will likely be on Wednesday night when northern
parts of the forecast area will reach to near 20 degrees,
meanwhile everyone else will be in the mid to upper 20s.
Temperatures moderate at the end of the week. Tlsjr
Challenging forecast with residual moisture and weak flow below
fl020 through the late evening.
In the interim, clearing to the east of mem should continue to
expand through the afternoon. For the evening, this region will
become increasingly favored for radiational fog or elevated
stratus formation. After 09z, fl020 winds will increase to
19025kt, with corresponding moisture axis/MVFR cloud deck lifting
north through MS. This higher deck would limit fog potential, but
there remains question if the MVFR deck would be preceded by an
underlying IFR deck from late evening radiational cooling
The rapid update rap and hrrr models appear to be adapting to
short term trends. 12z NAM and GFS lamp guidance failed to handle
the first 3 to 6 hours, and should be of limited utility until
stronger synoptic low level flow arrives late overnight.