Area Forecast Discussion
Issued by NWS Memphis, TN

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FXUS64 KMEG 201724
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
1124 AM CST Wed Feb 20 2019

.DISCUSSION...
Updated for 18Z Aviation Discussion.

&&

.PREV DISCUSSION... /issued 1057 AM CST Wed Feb 20 2019/

.UPDATE...

Rain has finally moved out for areas west of the Mississippi
River, but persists across northeast Mississippi and portions of
west Tennessee at this hour. We have had numerous report of flash
flooding and river flooding in the aforementioned area this
morning. Latest Hi-Res models suggest the showers will hang around
for another hour or two and then become more isolated in nature.
Thus, have decided to keep the Flash Flood Watch going until
current flash flood warnings and rain have moved out of the area.

A cold front is currently moving slowly into northwest portions
of the forecast area, with surface winds now westerly.
Temperatures are expected to remain steady for an hour or two and
then begin to gradually fall throughout the day as drier and
cooler air advect in behind the front. In fact, most locations
have reached their high temperature for the day.

Went ahead and adjusted temperatures down accordingly and trimmed
POPs down after 21Z this afternoon. Will cancel flash flood watch
within the next hour or so as precipitation eventually moves east
of the area. The rest of the forecast is in good shape.

AC3

&&

.PREV DISCUSSION... /issued 550 AM CST Wed Feb 20 2019/

UPDATE...
Updated for 12Z Aviation Forecast Discussion.

.PREV DISCUSSION... /issued 349 AM CST Wed Feb 20 2019/

.DISCUSSION...

A busy early morning is ongoing across the Mid-South. The latest
radar imagery depicts a line of showers and thunderstorms now
pushing into the eastern reaches of the FA, with lighter showers
well behind the line. A robust LLJ has driven this convection
overnight, and caused compression issues with incoming aircraft to
Memphis International. As this jet progresses east so will the
convection, gradually departing the region by mid morning.

The latest HRRR guidance suggests showers quickly coming to an
end, much quicker than models have indicated the last couple of
days. QPF values for the remainder of the Flash Flood Watch
period, or through 12z on Thursday, indicate under one tenth of an
inch of additional rainfall is expected across eastern Arkansas.
As such, have cancelled the Watch for counties west of the
Mississippi River. More counties will likely be able to be
cleared by late morning as precipitation evades the region.

Portions of northeast Mississippi could still see up to an inch,
or even more in thunderstorms, of rain through midday as PWAT
values remain around 1.60 inches there through 18z. Otherwise,
precipitation will come to an end for the entire region as a weak
front moves west to east by the evening hours. Temperatures this
afternoon will be realized generally in the 50s area wide, though
some of NE MS could reach the lower 60s.

The front will stall just south of the region, just to begin
inching north again early on Thursday. This will keep the dry
period quite short, as precipitation will begin to overspread the
region once again by Thursday afternoon. Weak impulses embedded
in the SW flow aloft interacting with this weak front could lead
to more intense showers and a few elevated thunderstorms late on
Thursday and into Friday. Thursday temperatures will be in the
upper 40s to mid 50s.

Temperatures will vary from the mid to upper 60s south to the
upper 40s north on Friday as the stalled front bisects the
region. Rain, which could be heavy at times, will stick around for
much of the day with the front stalled and interactions with weak
impulses aloft. By early Saturday a trough has moved into the
Southern Plains, deepening a surface low over the TX and OK
Panhandles. This will enhance southerly flow across the local
region as the boundary surges north as a warm front, allowing
temperatures to warm into the low to mid 70s for much of the area
on Saturday afternoon.

With the upper trough taking a bit of a negative tilt over the
region, a few strong to severe thunderstorms still appear possible
on Saturday afternoon and evening. A front clears the region early
on Sunday, bringing an end to the precipitation. Latest QPF values
for the Thursday PM through Sunday AM precipitation is between 2
to 3.5 inches for the entire region. Further monitoring will be
necessary, given antecedent conditions, for the potential for
flooding.

Drier conditions on Sunday and Monday will give way to additional
rain chances on Tuesday as a storm system strengthens along the
Gulf Coast. Temperatures will be quite seasonable early next week.

ZDM

&&

.AVIATION...
18Z TAFs

Weak cold front passing through MKL and TUP will bring an end to
the light showers...but cloud cover causing IFR and MVFR
conditions with the front will linger. Confidence is only low to
moderate for VFR weather at the sites tonight as fog and stratus
won`t be far off...especially at TUP and MKL. Later in the period
VFR conditions appear unlikely at all the sites as showers start
to surge back north. Generally light winds under 10kts from the
south or west will veer north and northeast.

JAB

&&

.AVIATION...


&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...Flash Flood Watch through late tonight for Alcorn-Benton MS-
     Calhoun-Chickasaw-Coahoma-DeSoto-Itawamba-Lafayette-Lee MS-
     Marshall-Monroe-Panola-Pontotoc-Prentiss-Quitman-
     Tallahatchie-Tate-Tippah-Tishomingo-Tunica-Union-Yalobusha.

TN...Flash Flood Watch through late tonight for Benton TN-Carroll-
     Chester-Crockett-Decatur-Dyer-Fayette-Gibson-Hardeman-
     Hardin-Haywood-Henderson-Henry-Lake-Lauderdale-Madison-
     McNairy-Obion-Shelby-Tipton-Weakley.

&&

$$


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