Area Forecast Discussion
Issued by NWS Memphis, TN

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FXUS64 KMEG 281727
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
1227 PM CDT Sat Mar 28 2020

.UPDATE...
Updated 18Z Aviation Discussion.

&&

.PREV DISCUSSION... /issued 1039 AM CDT Sat Mar 28 2020/

UPDATE...

1030 AM update. Temperatures are holding steady in the low to mid
70s with dewpoints in the mid to upper 60s. Latest SPC
mesonanalysis depicts about 1000 J/kg of MLCAPE at this hour with
a decent cap in place. A 2000 foot deck of stratus has developed
across the area, which should limit the amount of heating today.
Highs will likely peak in the upper 70s to lower 80s over
northeast Mississippi yielding as much as 2500 J/kg of SBCAPE
across much of the area. The atmosphere will certainly be unstable
enough to support severe thunderstorms later this afternoon and
into the evening hours as a cold front sweeps across the area.

However, the setup continues to look a bit messy with a variety
of storm modes possible. Initially storms are expected to develop
over northeast Arkansas and the Missouri Bootheel just ahead of
the cold front. These storms may be discrete in nature and pose a
risk for all hazards including tornadoes. Forecast soundings show
as much as 2500 MLCAPE over this area with large looping
hodographs, suggesting supercells will be possible. As the cold
front catches up this evening, the storm mode may morph into
broken line segments with the risk for embedded circulations.
Shear is expected to become a little more unidirectional in time,
and a QLCS looks probable as the line congeals. Damaging winds
would then become the main threat. Still, bulk shear will be on
the order of 65-80 kts, posing a risk for QLCS tornadoes as well.
The threat for severe thunderstorms should push east of the
Tennessee River just after midnight, with a few trailing showers
into the overnight hours. Temperatures are not expected to fall
much, as the front is of Pacific origin.

No big changes were made to the grids at this time.

AC3

PREV DISCUSSION... /issued 620 AM CDT Sat Mar 28 2020/

UPDATE...Aviation Discussion.

PREV DISCUSSION... /issued 543 AM CDT Sat Mar 28 2020/

GOES 16 Satellite imagery shows mostly cloudy skies across the
Mid-South which has helped keep temperatures up across the region.
Current observations show a very warm and humid airmass is in
place, especially for this time of year. Temperatures are in the
low 70s with dew-points in the mid 60s to low 70s. Strong
southerly flow is ushering in the airmass ahead of mature wave
that surface analysis charts show is currently over southwestern
KS. The associated warm front stretches into central KS, northern
MO, and central IL. The cold front is situated over KS, western
OK, and central TX which is what is expected to bring severe
weather across the region later today. Observed 00Z Skew-Ts across
LZK and BNA show an already unstable airmass is in place with
absolutely unstable mid-level lapse rates and CAPE greater than
1,200 J/kg, in addition to high bulk shear.

As the low pressure system tracks through the southern great
plains and upper-Midwest, a widespread severe outbreak is
expected to unfold with what appears to be a very concerning
situation for areas closer to the triple point later this
afternoon and evening. For the Mid-South, while it appears we
likely won`t see widespread discrete cells like the areas that are
in a Moderate risk across parts of the Midwest, the severe
weather threat has increased this morning. Short term models and
CAMS show a more unstable airmass than what guidance previously
had been showing. Additionally, guidance suggests that a broken
line of storms will develop ahead of the cold front early this
evening across northeastern AR and the MO Bootheel. This setup
would be more conducive of discrete cells developing and a
greater severe weather potential. Storms will likely become more
linear as the front pushes east into western TN and eastern MS.
Therefore, the best chance for seeing severe storms across the
County Warning area (CWA) will be over eastern AR, the MO
Bootheel, western TN, and western MS. Latest guidance shows CAPE
exceeding well over 2,000 J/KG and as high as 3,500 J/kg over
parts of the Mid-South, SPC as high as 15 in some areas, and
conditionally to absolutely unstable low-level lapse rates.
Additionally, DCAPE is forecast to be greater than 1,000 J/kg
which suggests strong downdrafts, in addition to very high bulk
shear. I would not be surprised if the Enhanced risk is expanded
further south by the SPC in the aforementioned areas. The primary
threats will be damaging winds, large hail, and a few tornadoes,
especially over the areas previously mentioned. As you head east
of I-40, the storms will become more linear and the threat will
become more of a damaging wind concern. Highs are expected to
reach the upper 70s to mid 80s with dew points in the low 70s to
around 80.

High pressure will build in to end the weekend with cooler
temperatures as we drop into the 50s overnight and top out in the
low 70s for highs on Sunday. The workweek will start of dry ahead
of our next system with highs in the upper 60s to low 70s.

Monday night and into Tuesday a low pressure system will track
through parts of the area and bring persistent showers and storms
through Tuesday evening/early Wednesday. Highs will be slightly
below to near normal with lows in the 40s. We`ll dry out to end
the week with temperatures a few degrees below normal.

KRF

&&

.AVIATION...
/18Z TAFs/

MVFR CIGs are expected to prevail for most of the day today along
with strengthening southerly winds and gusts up to 25 kts. A line
of showers and thunderstorms is expected to move quickly across
the Mid-South late evening. Showers should move into JBR by 22Z
then progress eastward through the night. Temporary IFR conditions
due to heave rain is likely in association with thunderstorms
along with gusty winds with thunderstorms. Winds will diminish
overnight to less than 10kt, shifting southwest to west. Skies
will likely clear by early morning and persist through Sunday.

SGW

&&


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

$$



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