Area Forecast Discussion
Issued by NWS Memphis, TN

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FXUS64 KMEG 201523
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
1023 AM CDT Fri Apr 20 2018

.UPDATE...

Forecast is on track with no major changes needed at this time.

AC3

&&

.PREV DISCUSSION... /issued 314 AM CDT Fri Apr 20 2018/

DISCUSSION...
A strong trough continues to dig over the western CONUS,
approaching the Four Corners this morning. Downstream of this
trough, shortwave ridging is providing generally dry conditions
to the Plains and Mississippi River Valley. The Mid-South is
firmly entrenched within a Continental Polar air mass with the
surface anticyclone sitting over the Upper Midwest. Clear skies
and light winds have allowed temperatures to fall into the 30s
across the Tennessee Valley, right in line with the current Frost
Advisory. Northeast winds will increase to 8-12 mph today once
vertical mixing commences and temperatures will rebound into the
60s. Otherwise, not a lot going on across the region in the short-
term.

The front over the Gulf of Mexico will retreat poleward as a warm
front on Saturday. Winds will veer southeasterly and temps will
warm into the lower 70s across much of the CWA. The aforementioned
Four Corners trough will be crossing the Plains at this time, and
large scale forcing for ascent will overspread the region. Cloud
cover will increase across the Mid-South but a strong capping
inversion will limit precipitation chances during the daytime
hours.

The cap is expected to diminish during the evening and overnight
hours as the trough inches closer. Numerous showers, and a few
thunderstorms, will move into the Mid-South Saturday night,
continuing throughout the day Sunday. This cyclone will be nearly
vertically stacked by the time it reaches the Mississippi River,
and as the cyclone occludes, a new surface low is progged to
develop over MS. Winds will back from the east and eventually
northeast as the low treks south of the forecast area. This will
bring cooler air into the region with the passage of a traditional
cold front. Warm advection above the surface layer will promote
widespread showers, and a few thunderstorms, on late Saturday
night through Sunday evening. Precipitable water is progged to
increase to ~1.25" early Sunday and will support decent rainfall
rates. Total QPF for the weekend ranges from 1-2" with the lowest
rainfall totals along the MO/KY borders and highest amounts
anticipated over north MS.

Light rain showers are expected Monday on the backside of the
departing trough. QPF will remain light during this period and
temperatures will remain in the 60s within the post-frontal air
mass. A few showers may linger into Tuesday east of Mississippi
River, but these rain chances will remain rather low. However,
we will see another opportunity for rain showers on Wednesday as
a fast-moving trough dives southeast across the Ohio Valley. This
trough will drive a cold front through the area, resulting in
slightly cooler and dry weather to end the work week.

Johnson

&&

.AVIATION...
12Z TAF cycle

VFR conditions will persist for the entire forecast period. Winds
will be mainly from the northeast at 5 to 10 knots for much of the
forecast period.

ARS

&&

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

$$


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