Area Forecast Discussion
Issued by NWS Shreveport, LA

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000
FXUS64 KSHV 221212
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
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 lowSome
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  66  53  71  53 /  10  10  10  10
MLU  73  53  69  53 /  50  10  20  10
DEQ  63  50  70  48 /  20  10  10  10
TXK  64  52  70  52 /  20  10  10  10
ELD  68  52  69  51 /  30  10  20  10
TYR  65  51  73  52 /  10   0   0   0
GGG  65  52  72  52 /  10   0   0   0
LFK  69  52  74  54 /  10   0   0   0

&&

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

$$

09/15


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