Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Memphis Tennessee
1120 am CST Thursday Dec 12 2013
Updated to include the 18z aviation discussion below.
Discussion... /issued 952 am CST Thursday Dec 12 2013/
Skies are mostly sunny across the forecast area this morning with
temperatures ranging from the lower 20s to middle 30s. Temperatures
are warming up a little more than expected mainly over area where
there is no snow cover so have made adjustments to some highs for
Previous discussion... /issued 617 am CST Thursday Dec 12 2013/
Currently...a 1038mb high pressure center is located over
southern Missouri and northeast Arkansas. As of 4am...temperatures
across the middle-south are in the low 20s in the north...with upper
20s in the south with a light northeast wind around 5 miles per hour
areawide. Temperatures will cool a few degrees more this morning
before quickly warming once the sun comes up. However...highs are
only expected to reach into the 30s across the northern
counties...with low 40s expected in the south as cold air advection will continue
through this afternoon.
Short term...tonight through Saturday...
a closed upper level low pressure system off the West Coast will
open into a wave during the day today...and trek across The
Rockies by Friday morning. As it does...a shortwave trough will
eject across the plains and a surface low will develop on the Lee
side of The Rockies. The surface low will track southeastward
across northern Texas and pull moisture up from the Gulf and into
the middle-south by Friday afternoon. Chances for rain will begin middle
to late afternoon on Friday and continue through Saturday midday.
Model soundings still continue to show the possibility of some
sleet and freezing rain across the northern tier counties. This is
also highly dependent upon how quick the atmosphere saturates in
the lowest levels and if this happens before warm air moves in
from the south. Another wave directly behind this system will move
the rain out of the area rather quickly. Most showers will taper
off by Saturday afternoon across the mid-south. High pressure will
immediately build in behind the front...although the air behind it
will not be quite as cold as the last few systems.
Long term...Sunday through Wednesday...
models are in decent agreement that high pressure will remain over
the middle-south through at least Wednesday. A weak and dry cold front
will pass to our north on Monday night...but will have little
effect if any on our region. Temperatures will rebound into the
50s by Tuesday and Wednesday as high pressure at the surface
dominates. Beyond Wednesday...model solutions are significantly
different with respect to each other and the overall pattern. The
GFS continues with the split flow pattern aloft...while the European model (ecmwf)
tries to build a ridge over the West Coast. For now...going to go
with a blend and keep temperatures in the 50s for Wednesday and
18z taf cycle (12/18z-13/18z)
VFR conditions will occur through the period. Light winds this
afternoon and tonight. Winds Friday morning southeast-S 6-7 kts.
Preliminary point temps/pops...
mem 39 30 45 37 / 0 0 50 90
mkl 38 21 45 35 / 0 0 30 80
jbr 31 25 38 33 / 0 0 50 90
tup 43 25 49 40 / 0 0 30 100