Area Forecast Discussion
Issued by NWS Memphis, TN

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000
FXUS64 KMEG 120020
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
620 PM CST Mon Dec 11 2017

.UPDATE...

Updated for 00z TAF discussion

&&

.PREV DISCUSSION... /issued 324 PM CST Mon Dec 11 2017/

DISCUSSION...
A Rex Block over the western CONUS will result in little change
in the synoptic pattern through Thursday, maintaining a mean
trough over the east and a ridge across the southwest. Closer to
home, a potent shortwave trough continues to dive southeast across
the western Ohio Valley this afternoon. The attendant surface low
has moved into northern IL with a trailing cold front extending
SSW across southeast MO into central AR. The resultant pressure
gradient has helped produce gusty southwest winds across the Mid-
South, with the strongest winds found over northeast AR into the
Bootheel. Relative humidity generally remains above 25% in most
areas, but has dropped slightly lower in a few locations. Winds
will veer westerly as 00z approaches, gradually shifting from the
northwest as a dry cold front moves across the Mid-South. Winds
are expected to remain up in the 8-14 mph range and may be gusty
at times throughout the night. No changes are anticipated to the
ongoing Red Flag Warning.

Northwest winds will increase again Tuesday morning but are
expected to slowly wane during the afternoon hours as the surface
gradient relaxes. Temperatures will take a big hit tomorrow with
afternoon highs only in the 40s. Mostly clear skies and a
decoupled boundary layer will result in cold temperatures across
the CWA for Wednesday morning. Expect sub-freezing temperatures
area wide with some locations dipping into the lower 20s. The
surface anticyclone remains south of the area, causing winds to
back southwesterly on Wednesday. Temperatures will be a bit
warmer, but most areas should top out in the low to mid 50s.

Another shortwave trough will swing across the region Thursday
into Thursday night. This will drive another cold front through
the area along with a bit of mid/upper-level moisture. A few
sprinkles and/or snow flurries aren`t out of the question Thursday
night, but confidence remains rather low at this time. Will
continue to monitor this potential over the coming days. This
Thursday cold front will reinforce the Continental Polar airmass
over the Mid-South, maintaining highs ranging from the mid 40s to
mid 50s.

A pattern shift is anticipated by the weekend as the east CONUS
trough moves east and a trough digs over the west. There remains
significant model disparity regarding the evolution of this
pattern, especially pertaining to the available moisture. At this
time, it appears that a cold front will move across the area on
Sunday as a relatively deep, positively tilted trough swings
through the Plains. The GFS continues to indicate a good amount of
QPF along this front while the ECMWF remains quite dry across the
region. Given this uncertainty, PoPs will be capped at 30-40% for
Sunday. This system will be a quick hitter with dry weather
expected early next week.

Johnson

&&

.AVIATION...
00z TAFs

VFR conditions to prevail, though a brief period of near MVFR
cigs are possible toward sunrise. A cold front is progressing
through the Midsouth, veering winds from southwesterly this
evening to northerly overnight. Winds will become gusty behind the
front, but the strongest gusts will hold off until during the day
tomorrow. Winds will diminish and gradually back to the west by
tomorrow evening as skies clear.

WLC

&&

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

$$



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