Area Forecast Discussion
Issued by NWS Shreveport, LA

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FXUS64 KSHV 162335
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
635 PM CDT Mon Apr 16 2018

.DISCUSSION...
VFR conditions to prevail yet again throughout the 00Z TAF pd. A
tightening pressure gradient will bring increasing sly winds
overnight across our wrn sites in E TX, eventually spreading ewd
to our remaining sites by just after sunrise. Sly winds 12-16 kts
will continue during the day Tuesday, with gusts 20-30 kts
possible at times. /12/

&&

.PREV DISCUSSION... /issued 404 PM CDT Mon Apr 16 2018/

DISCUSSION...
The afternoon sfc analysis indicates that the center of the sfc
ridging has shifted S into S LA/Nrn Gulf, with S winds having
already returned to the Wrn sections of E TX. As expected, temps
have warmed nicely to near 70/lower 70s over much of the region,
with the air mass expected to continue modifying overnight as S
winds return over the remainder of the area. In fact, the short
term progs suggest that a 40-50kt SWrly LLJ will develop late
tonight over the Srn Plains and much of the Ark-La-Tex region,
near and S of an inverted sfc trough that will develop late over
Nrn and Ern OK. The air mass remains quite dry in wake of our
latest cold fropa this weekend, thus not expecting a return of low
clouds tonight, although some cu may develop over portions of E
TX/Ern OK Tuesday before mixing out. The main concern in the short
term concerns the winds, as the LLJ axis will remain over the
region through Tuesday night. Thus, a portion of these winds will
mix down to the ground by mid-morning Tuesday, such that a Lake
Wind Advisory will be needed over much of the region, with some
areas remaining gusty Tuesday night. Will allow the mid shift to
pull the trigger on the Advisory, although later model runs will
have a better determination on which areas will need the Advisory
extended into Tuesday night. Given the strong Srly winds, max
temps Tuesday will quickly climb back above normal areawide, with
lower/mid 80s a good bet areawide.

The SWrly LLJ will remain strong Tuesday night as the progs
continue to advertise a weak cold front that will shift SE into
portions of N TX/extreme SE OK/Wrn AR by daybreak Wednesday, in
response to a large upper trough currently along the W coast,
which will eject across the Rockies Tuesday afternoon, and into
the Plains by Wednesday morning. This will result in an increase
in stratocu across at least the Wrn 2/3rds of the region by
daybreak Wednesday, with forcing (albeit within the shallow moist
lyr) to suggest isolated -SHRA development after 12Z over portions
of E TX/N LA/extreme Srn AR. Have maintained slight chance pops
over these areas Wednesday morning, although drier air will
quickly begin to spill back SE in wake of the front. Not expected
much of a cooldown with this next front, with warm/seasonable
afternoon temps and cool nights expected as sfc ridging helps
nudge the front out of the area by late Wednesday evening. This
ridging will persist over the region through late Friday, before a
SSE low level flow returns to the area Saturday ahead of a deep
bowling ball closed low that will drops SE across the Srn Rockies.

The 12Z GFS and ECMWF are in good agreement with the closed low
entering the Srn Plains Saturday morning, at which point sfc
cyclogenesis develops across NW TX and just S of the Red River of
N TX and traverses E. A Srly LLJ will again develop ahead of this
next system, with convection expected to increase during the
afternoon over OK/TX and spread E into the region late in the day
through Saturday night. There still remains some uncertainty
though as to the extent of the higher theta-e/dewpoint air
returning N along a retreating warm front, and thus the extent of
instability. However, strong shear profiles even with a
weak/modestly unstable air mass suggest the threat for svr
convection will again be possible over portions of the region. The
medium range progs has also slowed the system down slightly as
well, and should this continue, forecast CAPES may trend even
lower in future model runs. Have maintained likely pops for the
weekend, although delayed the onset of the higher pops Saturday
for Scntrl AR/Ern sections of Ncntrl LA until Saturday night.

Otherwise, drier air will quickly entrain ENE beneath the upper
low center and quickly taper the convection off for the latter
half of the weekend, with the potential for post-frontal stratocu
to keep cooler than normal temps in the area to start the new work
week next week.

Prelims to follow below...

15

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  49  83  62  79 /   0   0  10  20
MLU  45  82  60  78 /   0   0  10  20
DEQ  43  81  59  76 /   0   0  10  10
TXK  51  82  62  76 /   0   0  10  10
ELD  43  82  60  78 /   0   0  10  20
TYR  55  83  63  78 /   0   0  10  20
GGG  52  83  63  78 /   0   0  10  20
LFK  54  84  64  80 /   0   0  10  20

&&

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

$$

12/15



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