Area Forecast Discussion
Issued by NWS Memphis, TN

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854
FXUS64 KMEG 241713
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
1213 PM CDT Fri Mar 24 2017

.UPDATE...
Updated for wind advisory.

&&

.DISCUSSION...

Winds already reaching advisory criteria across northeast
Arkansas. These conditions will continue through the afternoon and
tonight. In addition...gradient winds may briefly diminish as the
anticipated convective line pushes through tonight...but increase
and slowly veer southwest tomorrow ahead of the cold front. Also
expanded the wind advisory farther west for later tonight into
tomorrow.

JAB

&&

.PREV DISCUSSION... /issued 623 AM CDT Fri Mar 24 2017/

DISCUSSION... /issued 422 AM CDT Fri Mar 24 2017/

A progressive and amplified upper level pattern will bring
weather more typical of mid-spring to the Midsouth through the end
of next week, including severe weather.

Tonight, a cut-off southern branch low will lift from the southern
plains to Ozark Plateau. This system will remain nearly vertically-
stacked, preceded by an attendant convective line that should
enter eastern Arkansas late in the evening. Model soundings
suggests the airmass over the Midsouth will remain capped to deep
convection today and early evening, though a few low-topped warm
advection showers can`t be ruled out along and west of the MS
River. Once the convective crosses the MS River around 06Z, it
should encounter decreasing instability during the overnight.

The cut-off upper low will slow its northeastward progress on
Saturday, under a broad upper ridge. A trof axis extending south
of the low will rotate into northwest MS / southwest TN Saturday
afternoon, helping to reorganize storms in an increasingly
unstable airmass. NAM Bufr sounding for Tupelo 19Z Saturday
depicted midlevels lapse of 6.5 C/KM, CAPE near 1200 J/KG. In
addition, a curved hodograph and low LCL suggest some potential
for tornadoes, ahead of the shortwave trof axis rounding the
upper low.

The upper low finally lifts out late Saturday night, leaving low
amplitude ridging and relatively quiet weather to prevail Sunday.
This quiet period will be short-lived, as another upper low, this
of northern branch origin, drops into the Midsouth from the plains.
Midlevel lapse rates with this northern branch wave are progged
to exceed 7C/KM, indicative of large hail potential given moderate
instability and adequate shear.

Looking toward the the latter half of next week, the ECMWF and GFS
depict a large cut-off low lifting east through the plains, toward
the lower MS River valley. This feature will have a couple days of
warm sector destabilization ahead of it. Both models suggest a
double-core nature to the upper low, which could be significant
if one lobe were to rotate around and eject in a negative-tilt
fashion as the GFS and ECMWF models suggest. Much time remains for
this system to evolve however, as the parent energy was still off
the Pacific northwest coast this morning.

PWB

&&

.AVIATION...

12Z TAF Set

Stratus is quickly invading the Mid-South from the SE at this
time. Expect all TAF sites to at least see a temporary reduction
to MVFR conditions between 12Z and 18Z. CIGS will lift to VFR
thereafter and will remain VFR until an expected squall line moves
into from west to east after 3Z. Strong southerly winds of 10-20
KTS sustained will occur over the next 24 hours. Higher gusts will
occur with possible gusts reaching up to 30 KTS during the
overnight period. CIGS and VSBYS will deteriorate with the squall
line.

KRM

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...Wind Advisory until 4 PM CDT Saturday for Clay-Craighead-
     Crittenden-Cross-Greene-Lawrence-Lee AR-Mississippi-
     Phillips-Poinsett-Randolph-St. Francis.

MO...Wind Advisory until 4 PM CDT Saturday for Dunklin-Pemiscot.

MS...Wind Advisory until 4 PM CDT Saturday for Coahoma-DeSoto-Tunica.

     Wind Advisory from 10 PM this evening to 4 PM CDT Saturday for
     Benton MS-Lafayette-Marshall-Panola-Quitman-Tallahatchie-
     Tate-Yalobusha.

TN...Wind Advisory until 4 PM CDT Saturday for Dyer-Lake-Lauderdale-
     Obion-Shelby-Tipton.

     Wind Advisory from 10 PM this evening to 4 PM CDT Saturday for
     Crockett-Fayette-Gibson-Hardeman-Haywood-Madison-Weakley.

&&

$$



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