Scientific Forecaster Discussion
fxus64 kmeg 130547
Area forecast discussion
National Weather Service Memphis Tennessee
1147 PM CST Thu Dec 12 2019
Updated for 06z aviation discussion.
Previous discussion... /issued 925 PM CST Thu Dec 12 2019/
A cool and quiet night across the mid-south. Temperatures are
generally in the mid 30s to lower 40s. Latest GOES nighttime rgb
channel shows a couple of distinct layers of clouds advecting
into the mid-south. An area of low stratus is slowly surging north
into north Mississippi at this hour, while a cirrus shield is
slowly spreading westward across central Arkansas. The Mississippi
Delta is sandwiched between these two cloud deck with prevailing
Went ahead and added patchy fog to areas along and west of the
Mississippi River, where clear skies and light winds will allow
fog to form. Hi-res guidance suggests that dense fog will be
possible over much of eastern Arkansas overnight as skies remain
mostly cloud-free. Short term trends will need to be monitored
closely over the next several hours for a dense fog advisory.
The rest of the forecast is on track with no further changes
Previous discussion... /issued 617 PM CST Thu Dec 12 2019/
Updated for 00z aviation discussion.
Previous discussion... /issued 337 PM CST Thu Dec 12 2019/
Discussion...surface analysis late this afternoon places a ridge
of high pressure along the East Coast of the United States while
an area of low pressure is in the Gulf of Mexico. GOES-16
satellite trends indicate predominantly high clouds moving across
the mid-south with some lower cloud cover occurring over extreme
northeast Mississippi. Southerly winds on the back side of high
pressure have allowed temperatures to moderate into the 50s across
most locations as of 3 PM CST.
Short term models continue to indicate the aforementioned area of
low pressure moving northeast towards the Florida Panhandle on
Friday. Meanwhile, a mid-level trough will move across the lower
Mississippi Valley on Friday. This will bring a potential of some
light rain first to portions of northeast Mississippi late
tonight into early Friday morning, and across areas east of the
Mississippi River during the day on Friday. A few rain showers
will be possible over far northwest Tennessee near the Tennessee
River Saturday morning. Otherwise, mainly precipitation free
weather is expected as shortwave ridging builds in behind the
departing mid-level shortwave trough.
Middle to long range models suggest the upper level flow will
become nearly zonal then transition to southwest flow aloft on
Sunday. Precipitation chances will increase on Sunday and
especially into Monday as a surface low develops in the Southern
Plains and moves into the lower Mississippi Valley on Monday. A
potential exists for a few strong to severe thunderstorms on
Monday but differences in the models leads towards lower
confidence for the time being until better consensus emerges in
subsequent model runs. Thus, will leave mention out of the
hazardous weather outlook for this forecast issuance.
MVFR will start off the taf period and become IFR by the early
morning hours. Ceilings will gradually lift by the afternoon hours
as a trough moves out of the region. VFR conditions are expected
to return by tomorrow evening. Winds will be light from the S/SW.
Br will also be possible for a few hours in the morning.
Confidence isn't great on how low visibility will reach in the
morning, however fog will mainly be focused along and west of the