Area Forecast Discussion
Issued by NWS Memphis, TN

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FXUS64 KMEG 102041
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
241 PM CST Sat Dec 10 2016

.DISCUSSION...

Currently temperatures across the Midsouth ranged from the mid
30s to mid 40s...with either calm or light southerly winds being
reported. Most of the region was sunny with clouds advancing into
eastern Arkansas and the Bootheel of Missouri.

Tonight through Tuesday...models are in very good agreement with
the current Pacific system sliding quickly east across the Rockies
and Plains over the next 48 hours. Water Vapor already indicating
mid and upper level moisture well ahead of the main trough near
the Oregon Coast. Southerly winds will increase across the Lower
Mississippi Valley tonight ahead off developing surface waves and
frontogenesis in the Central Plains/Midwest. This WAA will take
near 0C temperatures at 925mb to +10C by tomorrow afternoon...with
a broad isentropic surface initiating light rain west of the
Mississippi river before noon. This activity will slide east later
in the day...with the heaviest swath of precipitation expected
during the overnight hours as the cold front pushes through the
region. In addition...midlevel instability will allow for a few
claps of thunder. Chances for rain will wane Monday morning for
the north and west...but will be slow to exit in the southeast
until Monday night. Dry and seasonal weather will spread across
the entire Midsouth for Tuesday. High temperatures through the
period will range from the upper 40s north to near 60F south.

Wednesday and Thursday...arctic air over the Northern Plains and
Upper Midwest will sag southeast into the Ohio and Tennessee River
valleys this period...with the trajectory sliding just east of
the Midsouth thanks to a strong west to east upper flow. From this
have bumped up temperatures a few degrees both days...though they
will still be below normal. Weak high pressure will dominate with
dry conditions.

Next Weekend...the next system to affect the region is becoming
more interesting. Both the GFS and ECMWF show strong WAA beginning
Thursday night and on Friday as a deeper shortwave drops into the
Great Basin and Southern Rockies. Strong southwest upper winds
will quickly bring moisture back into the area...while modified
arctic air in the boundary layer retreats northward. How far north
is still uncertain due to the expected snowpack in the Midwest.
Precipitation timing is critical with these events...but for now
it appears that the rain onset will occur when the entire Midsouth
is above freezing. Later in the weekend rain could become moderate
to heavy at times with embedded thunder. Both models are showing
dewpoints reaching the low 60s on Saturday...though this may be a
bit of a stretch. Late Saturday night and on Sunday cold air on
the backside of the system will rush in before the moisture
exits...so have introduced frozen precipitation chances over the
northern counties. This could be the area`s first accumulations
of the winter season.

JAB

&&

.AVIATION...18z TAFs

VFR conditions are expected to prevail at all terminals through
the forecast period. Mid level clouds will slowly increase from
the west later this afternoon and evening. Overcast decks between
5-6 kft will be common by Sunday morning slowly lowering through
the end of the forecast period.

Winds will be light southeasterly today before increasing from the
south overnight and becoming gusty on Sunday morning.

JLH

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&

$$



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