Area Forecast Discussion
Issued by NWS Shreveport, LA

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000
FXUS64 KSHV 221441
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
941 AM CDT Sun Apr 22 2018

.UPDATE...
Scattered showers continued pushing east thus exiting the region,
though with the UA low just to our north, could see some lingering
showers pop up across portions of central and northeast LA and
southwest. Have trimmed POPs a bit but kept in chance POPs across
the aforementioned areas. Increased the max temperatures by a
degree or two, particularly across deep east TX and central LA as
model solutions hint at a bit of clearing later today.
Subsequently tweaked the dewpoint temperatures and relative
humidity values. Otherwise, forecast is largely on track with
lingering showers intermittently affecting the northern and
eastern zones throughout the day.

&&

.PREV DISCUSSION... /issued 712 AM CDT Sun Apr 22 2018/

AVIATION...
For the 22/12z TAFs, convection will continue to move east and
northeast across North Central Louisiana and portions of Southern
Arkansas, mainly east of a line from KAQV to KELD, for the first
few hours of the period. A cold front is rapidly moving across the
area. At TAF issuance, the front was located from near KELD to
near KJAS. The front and the rain should move east of all TAF
sites by 22/16z. Flight conditions vary around the area from MVFR
to IFR. Ceilings should lift into the MVFR range by 22/19z at most
locations. With the exception of KELD and KMLU, conditions at the
TAF sites may improve into the VFR range by sunset before more low
clouds move into the region from the north during the overnight
hours. Northwest winds will increase to between 10 and 15 kts with
gusts between 20 and 25 kts. Wind speeds should diminish slightly
after 23/00z.

/09/

PREV DISCUSSION... /issued 429 AM CDT Sun Apr 22 2018/

DISCUSSION...
The morning mosaic radar imagery indicates the convection gradually
diminishing from W to E this morning across Scntrl AR/N LA, as dry
air continues to entrain E ahead of the negative tilt upper trough and
associated closed low. Some portions of the area over OK. The 00Z
NAM/GFS and latest HRRR depict the back edge of the convection
should be exiting the Ern edge of the forecast area by or shortly
after 12Z this morning, and thus have toned down pops this morning
over these areas. However, the closed low will wobble ESE into
Wrn Ar this afternoon, which may result in isolated -SHRA
redevelopment over SE OK/SW AR and portions of Ncntrl LA late in
the day. Meanwhile, the morning sfc analysis and latest volume
scans from the KSHV 88-D depict a cold front making steady
progress E, extending from just E of TXK, to near ASL, to near
OCH/LFK, to just S of UTS as of 09Z. This front will continue to
make rapid progress E across Scntrl AR/N LA, exiting the region by
mid to late morning. Wrap-around stratus will persist even in
wake of the fropa this morning, with some improvement to cigs
possible later this afternoon over lower E TX. This cloud cover
and NW winds 10-15kts with higher gusts over much of the region
will result in cooler than normal temps this afternoon, with the
wrap-around stratocu likely lingering over much of the region
tonight and Monday as the closed low temporarily slows its Ewd
progress and spins over the Mid-South region. Should finally start
to see clearing commence by Monday night as this low finally
drifts farther E into the TN Valley.

A dry NW flow will linger in wake of the low`s departure Tuesday,
although strong insolation will result in a return to more seasonal
temps by afternoon as readings climb into the upper 70s to near 80
degrees. However, this will be short-lived as sharply positive tilt
shortwave rapidly drops SSE through the Cntrl Plains Tuesday night
into OK/AR Wednesday, which will reinforce a cold front quickly SE
through the region Wednesday. The GFS remains the faster solution,
bringing the front quickly into the area after 06Z Wednesday, exiting
the area by 18Z. The ECMWF remains about 6 hours slower, but both are
in agreement with post-frontal rains developing Tuesday night over
portions of OK/possibly N and NW TX, although considerable placement
of the rains differ significantly as well. Have kept the forecast
consistent with earlier runs, maintaining slight chance pops late
Tuesday night for SE OK, before ramping mid and high chance pops up
Wednesday along/N of I-20 over E TX/N LA. Do prefer the faster runs of
the GFS/Canadian though given the positive amplitude of the trough,
thus tapering pops off Wednesday night.

Model discrepancies increase by the mid and late week timeframe with
the ECMWF much sharper/farther S and a bit slower with a developing
longwave trough E of the Rockies, and also wetter with the next cold
fropa. This trough amplitude is deeper/stronger than earlier runs of
the ECMWF, but have maintained slight chance pops areawide Friday
despite the dry GFS/Canadian, with cool nights/mild afternoons
expected in wake of the front next weekend, which would be seasonable
for this time of year. Fortunately, with the progressive nature of the
upper level flow this next week, severe storms (or even thunder) are
not expected through the forecast period.

Prelims to follow below...

15

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  67  53  71  53 /  10  10  10  10
MLU  72  53  69  53 /  50  10  20  10
DEQ  65  50  70  48 /  20  10  10  10
TXK  64  52  70  52 /  20  10  10  10
ELD  69  52  69  51 /  20  10  20  10
TYR  66  51  73  52 /  10   0   0   0
GGG  66  52  72  52 /  10   0   0   0
LFK  70  52  74  54 /  10   0   0   0

&&

.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&

$$

29/09/15


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