Area Forecast Discussion
Issued by NWS Memphis, TN

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FXUS64 KMEG 190323
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
923 PM CST Tue Feb 18 2020

.UPDATE...

Showers are still ongoing across north Mississippi at this hour.
The front is now well south of the area, however, broad southwest
flow has resulted in numerous post-frontal clouds and rain across
the southern half of the area. Clouds will slowly erode across
the north overnight as surface high pressure nudges in from the
northwest. Across the southern half of the area, expect light
rain and clouds to hang around through early Wednesday morning.

The current forecast is in good shape.

AC3

&&

.PREV DISCUSSION... /issued 537 PM CST Tue Feb 18 2020/

UPDATE...
Updated 00Z Aviation Discussion.

&&

.PREV DISCUSSION... /issued 320 PM CST Tue Feb 18 2020/

DISCUSSION...
A surface cold front passed through the I-40 corridor this morning
and through Tupelo around 1 pm. In the time since, southward
progress had slowed and training of low-topped storms along the
front had resulting in rainfall of 2 to 3 inches over Monroe
County since mid-morning. Relief from the persistent rainfall
will arrive with midlevel height falls this evening, which will
drive the cold front and associated rain focus to the south.

Predominately dry conditions will prevail across the Midsouth on
Wednesday, with rain focus further south along the I-20 corridor.
Over the Midsouth, a cool and dry continental polar airmass will
prevail, overspread by scattered to broken high clouds.

For Wednesday night, a 250mb speed max over the Ohio Valley is
progged to increase to 175 knots. Divergence associated with the
right entrance region of this speed max, along with an influx of
midlevel moisture will return precip to the Midsouth by sunrise
Thursday. Thermal profiles will be marginally favorable for a
rain/snow mixture - if the precip can make it through the dry sub-
cloud layer to the ground. At this point, it`s not clear there`ll
be sufficient lift to overcome the dry air, but 12z model-blended
PoPs were a bit higher than earlier. There is better confidence
for measurable precip over north MS early Thursday, where the
frontal inversion is more shallow and more easily saturated - but
with thermal profiles more favorable for rain. In any case,
Thursday morning`s low temps will remain above freezing across
the Midsouth and no winter precip accumulations are forecast.

By late Thursday afternoon, a northern branch trof will drop from
the central plains into the mid and lower MS River valley,
driving precip well to the east. A reinforcing Arctic cold front
will pass, followed by the center of the Arctic high settling into
the Midsouth Friday evening. Saturday morning`s lows will drop
into the 20s regionwide, with some teens not out of the question
near the TN river.

A fast-moving southern branch low pressure remains on track for a
Sunday passage through the mid-MS River valley. Model-blended
precip progs depicted rain well in advance, topping the downstream
shortwave ridge Saturday afternoon. Measurable rainfall appears
premature Saturday afternoon, given the dry Arctic air. Airmass
over the Midsouth should moisten and warm Saturday night, and
expect Sunday to hold likely chances of rain for the Midsouth. GFS
and ECMWF MUCAPE progs continued to show little to no instability
with this system, limiting the severe weather concerns at this
time.

PWB

&&

.AVIATION...
/00Z TAFs/
MVFR conditions are expected to persist through this
evening eventually becoming VFR by tomorrow morning at MEM, MKL
and JBR. As for TUP, IFR ceilings will likely persist through the
morning as a cold front moves away form the area. Expect
occasional -RA/SHRA with the potential for heavier rain around
TUP. CIGs so far have already improved to VFR, however, confidence
is low that this will continue. If CIGs do remain persistent for
the next couple hours (especially at MEM) expect an amendment.
Winds will be out of the NNE with occasional gusts around 20 kts.

SGW

&&

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

$$


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