Area Forecast Discussion
Issued by NWS Shreveport, LA

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000
FXUS64 KSHV 231029
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
529 AM CDT Mon Apr 23 2018

.AVIATION...
Wraparound stratocu behind a closed low movg slowly east across
the lower MS River Valley will spread mainly low vfr cigs across
LA/AR portions of the area thru the mrng hours, and possibly
across portions of ne TX thru mid mrng. Brief high mvfr decks are
possible with clouds gradually scattering out durg aftn as nw
winds increase to around 10 kts with ocnl higher gusts. Skies
becmg mostly skc after 24/00z with a few clouds lingering across
kmlu and keld until around 24/03z. Aside from possible brief mvfr
vsbys after 24/10z at mainly these sites where clearing skies are
delayed and ground remains wet after nw winds decouple, vfr to
continue thru end of overnight fcst cycle./07/


&&

.PREV DISCUSSION... /issued 427 AM CDT Mon Apr 23 2018/

DISCUSSION...
The morning satellite imagery indicates a considerable wrap-around
stratocu field over portions of NE TX/N LA, and all of SW AR and
SE OK, WSW of the closed low spinning over NE AR/Wrn TN (the Mid-
South region). The short term progs are in good agreement this
morning with this stratocu field expanding farther SE across the
remainder of N LA and portions of E TX, although these cigs may
try and scatter out this afternoon over portions of E TX as the
closed low, which will remain nearly stationary today over the
Mid-South, begins to finally nudge E into the TN Valley late in
the day through this evening. Should begin to see some modification
in max temps though today, but still remain some 5-8 degrees below
normal, with the wrap-around cu field expected to diminish further
this evening. Many of the short term progs (including the
GFS/ECMWF/HRRR) are also in agreement with the potential for
isolated -SHRA developing this afternoon as a shortwave lobe
rotates SSE across Cntrl and SE AR around the center of the closed
low, and thus have re-added slight chance pops for portions of
Scntrl AR and the NE sections of Ncntrl LA. Any -SHRA development
should diminish by or shortly after 00Z Tuesday, with weakening
WNW winds and a clearing sky resulting in another night of cool
and comfortable temps. A sct cu field may redevelop by midday
Tuesday over the Ern half of the area, but otherwise, strong
insolation and height rises aloft in wake of the departing closed
low will result in max temps topping out near seasonal norms in
the upper 70s to near 80. This will be the warmest day this week,
as temps will cool down by mid and late week with a series of cold
frontal passages.

The first of these fronts will quickly slide SE into the area
Wednesday, well ahead of a nearly W-E shortwave trough that will
shift SE from KS/MO SE into AR/OK/N TX late in the day. The progs
are in much better agreement this morning with some post-frontal
convection developing over NW TX/OK Tuesday night, traversing ESE
into the Nrn half of the region Wednesday. Given the lack of any
Srly return flow, the dry air mass will have to saturate from the
top down, affecting primarily areas along/N of the I-20 corridor
of E TX/N LA Wednesday. Given the higher confidence with relative
placement and timing, have bumped up pops to high likelies N of
I-30, and have continued with the tapering of mid/high chance pops
closer to I-20. Have expanded mid chance pops farther S Wednesday
night as the trough amplifies when it swings SE into the Lower MS
Valley. However, some uncertainties remains as to the extent of
QPF given the continued top down saturation of the air mass,
although the potential for SWrly H850 winds late Wednesday night
may result in better low level moisture advection and hence
slightly higher QPF`s over the SE sections of Ncntrl LA before the
trough and associated dynamic forcing exits the area.

This progressive flow regime will continue through late week, as
which point another deeper longwave trough will quickly drop SE
through the region Friday. The GFS/Canadian remain the more
progressive solutions though compared to the slightly slower
ECMWF, and also produce much less in the way of QPF as well with
this next cold fropa. Have thus maintained slight chance pops
areawide until better model consensus can be achieved during this
portion of the forecast period. However, a dry NW flow aloft
through at least the first half of next weekend should yield mild
afternoon temps and cool nights until a warming trend with higher
RH`s commence for the first of next week.

Prelims to follow below...

15

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  72  54  80  57 /   0   0   0   0
MLU  71  54  77  54 /  20  10   0   0
DEQ  71  48  78  52 /  10   0   0  10
TXK  71  53  78  55 /  10   0   0  10
ELD  70  51  76  53 /  20  10   0   0
TYR  72  54  80  57 /   0   0   0  10
GGG  71  54  79  55 /   0   0   0   0
LFK  75  55  81  57 /   0   0   0   0

&&

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

$$



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