Area Forecast Discussion
Issued by NWS Memphis, TN

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FXUS64 KMEG 191132
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
532 AM CST Wed Dec 19 2018

.UPDATE...
See the 12z aviation discussion.

&&

.PREV DISCUSSION... /issued 316 AM CST Wed Dec 19 2018/

DISCUSSION...

High pressure remains over the Mid-South this morning. Skies are
mostly clear for the most part as the CWA is between areas of
cirrus. Dense fog has developed just to the southwest of the CWA.
The HRRR continues to show the fog spreading into portions of
Northwest Mississippi and East Central Arkansas over the next
couple of hours. As a result, will continue with the Dense Fog
Advisory.

Clouds will spread back into the area over the course of the day
ahead of a low pressure system that is developing along the Gulf
Coast. Showers ahead of the system may start moving into portions
of North Mississippi and East-Central Arkansas late this
afternoon. However, the bulk of the rain will hold off until
tonight. Expect a band of showers to lift into North Mississippi
during the evening hours and then lift northward to the I-40
corridor around midnight. The band will then continue lifting
northward to the KY/TN border by 5-6 AM. Other than this band,
expect showers to be isolated or scattered in nature.

The SFC low will be located in Alabama by Thursday morning. Thus
there may be a break in the rain before the upper trof moves
through the area during the afternoon hours. Models do show a
second band developing with the trof but how extensive it is
varies amongst the models. Chances for rain will taper off from
west to east Thursday Night as the upper trof shifts east.
However, rain chances will continue on Friday near the Tennessee
River due to the slow movement of the system.

Cooler temperatures will occur on Friday due to gusty northwest
winds, cold air advection, and lingering cloud cover. Expect highs
to remain in the 40s.

The cooler temperatures will be short-lived as winds quickly turn
around to the south by the weekend. Saturday highs should warm
back into the mid to upper 50s for much of the area.

A cold front will move into the Mid-South during the latter part
of the weekend. The ECMWF shows rain breaking out across portions
of West Tennessee and North Mississippi Sunday afternoon while the
GFS is dry. This is where differences between the two models begin
as the ECMWF never pushes the front to the Gulf Coast, stalling it
across Central Mississippi before lifting it back to the north as
a warm front Monday Night into Tuesday. Meanwhile, the GFS pushes
the front to the Gulf Coast which allows SFC high pressure to
build over the Mid-South Monday into Monday Night. Thus confidence
in the Christmas Eve and Christmas forecast remains low. Will
continue with small POPS for both time periods for now.

KRM

&&

.AVIATION...
/12z TAFs/

Patchy low clouds have developed across the Delta counties this
morning, but ceilings have managed to evade the forecast
terminals. In general, expect scattered stratocu around 2500 ft
through this afternoon with some tempo ceilings across the CWA.
Showers will increase across the CWA this evening, becoming
widespread overnight. IFR ceilings are expected to develop around
or just before 06z with prevailing -RA and reduced visibility. The
main area of rain should begin to pull off to the east by 12z but
periods of drizzle and light rain showers may persist through
Thursday morning. Winds will be light from the south today,
eventually backing from the northeast overnight.

Johnson

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...Dense Fog Advisory until 9 AM CST this morning for Lee AR-
     Phillips.

MO...None.
MS...Dense Fog Advisory until 9 AM CST this morning for Coahoma-
     Quitman-Tallahatchie-Tunica.

TN...None.

&&

$$


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