Area Forecast Discussion
Issued by NWS Memphis, TN

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FXUS64 KMEG 220838
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
338 AM CDT Fri Sep 22 2017

.DISCUSSION...
The synoptic pattern is highlighted by SW-NE oriented upper-level
ridge extending from the Southern Plains into the Great Lakes.
Post-Tropical Storm Jose is located just east of this ridge off
the New England coast and a deep, quasi-stationary trough is noted
over the western CONUS.

The pattern is expected to chance little over the next 24 hours,
but the ridge is progged to slide a bit farther north as we move
into the weekend. Thus, a persistence forecast is in order for
today with max temps very near yesterday`s highs. Weak capping
associated with the ridge aloft should limit the coverage of
diurnal convection. Isolated showers and thunderstorms were only
included in today`s forecast over northeast MS, but a stray
shower can`t be completely ruled out anywhere in the CWA. Heat
indices will remain an inconvenience today with maximum values
progged to range from 95-101 degrees this afternoon.

As the ridge slides north this weekend, slight cooling in the
mid-levels should put temperatures on a very slow cooling trend.
High temperatures will still be in the upper 80s and lower 90s
through the weekend but are forecast to drop below 90 degrees
area wide by Monday. This mid-level cooling will also weaken the
cap aloft, allowing slightly more coverage of diurnally forced
convection. The weak upper-level low over the Southeast is progged
to drift toward the southern portion of the CWA by Sunday and
this could enhance rain chances slightly. However, PoPs remain in
the 20-30% range at best through the weekend.

This upper-low becomes less of an influence by Monday as it begins
to feel the influence of Hurricane Maria`s broad cyclonic
circulation. As this happens, subsidence will increase across
the region once again, limiting rain chances. As we move into the
midweek period, the stubborn upper-level ridge finally breaks down
and allows the western CONUS trough to move slowly east. The
global models are in fair agreement that large-scale forcing will
remain west of the CWA through Tuesday, but ascent will begin to
increase Wednesday and Thursday as ridge flattens and we see some
shortwave energy moving across the region.

While there still remains a fair amount of uncertainty, there are
indications that we`ll see more substantial rain chances and
cooler temperatures during the latter half of the work week. The
general consensus is that a cold front will move through the Mid-
South sometime around Thursday but there is less agreement in the
rainfall potential. Will keep an eye on how the pattern evolves.

Johnson

&&

.AVIATION...
/06Z TAFs/

VFR...with a potential morning period of IFR/MVFR VSBY from fog.
Calm or light and variable winds overnight will become easterly at
4-5kts before noon.

JAB

&&

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

&&

$$



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