816 
FXUS64 KSHV 181757 AAA
AFDSHV

Area Forecast Discussion...UPDATED
National Weather Service Shreveport LA
1257 PM CDT Sun Jul 18 2021

.AVIATION...
Mostly VFR conditions will continue through the 18/18Z TAF 
period, although periods of convection will continue to develop
this afternoon over portions of SE OK/SW AR as they build SE into
extreme Nrn LA. This will result in periods of MVFR cigs, reduced
vsbys, and wind gusts to 35kts, particularly at the TXK/MLU 
terminals. Additional convection redevelopment should occur
farther W into extreme NE TX later this afternoon/evening, with a
bkn line of convection gradually drifting S across E TX/extreme
Srn AR/N LA this evening through the overnight hours, affecting
the I-20 terminals of E TX/N LA. This may also result in locally
reduced cigs, vsbys, and higher wind gusts, with subsequent 
TAF's better able to delineate these conditions. This convection
should shift S of I-20 by mid-morning Monday, with LFK the last to
be affected from mid-morning through the afternoon. With the
clearing of the convection, elevated convective debris will
linger, although some cu/stratocu cigs may develop by mid to late
morning across SW AR. Also can't rule out brief MVFR cigs
developing late tonight over portions of Deep E TX/NCntrl LA ahead
of the convection. SW winds 4-8kts this afternoon will become VRB
5kts or less after 00Z, except strong/gusty in/near the developing
convection. /15/

&&

.PREV DISCUSSION... /issued 1040 AM CDT Sun Jul 18 2021/ 

SHORT TERM.../This Afternoon/

The latest radar imagery continues to depict a cluster of
convection traversing SE across the Nrn sections of SW AR, along a
weak shortwave trough digging SE across extreme NE TX/SE TX/Wrn
AR. The morning sfc analysis reveals that this convection has
generated a weak cold pool across Wrn AR, well ahead of a weak sfc
frontal bndry extending from Ern KS to along the AR/MO border. The
12Z NAM and latest HRRR runs have initialized well on the ongoing
sfc and upper level features, and suggest that this convection
will expand SE across portions of SW and especially SCntrl AR
through the afternoon, and possibly into the extreme Nrn sections
of NE LA near/N of MLU by mid and late afternoon. Radar also
indicated sct convection developing along the SW flank of this
shortwave across portions of N and NE TX, which may persist/even
shift NE into extreme NE TX during the afternoon where forcing
aloft will be a bit stronger with the passing trough. Additional
convective development is possible later this afternoon N of this
trough near the OK/AR border near and S of FSM, along the weak 
sfc front and associated H850-700 trough as it slowly drifts S 
into SE OK/Cntrl AR. This convection is progged to affect portions
of MCCurtain County OK and the Nrn sections of SW AR again by mid
to late afternoon behind the initial convective push.

For the forecast update, did have to trim pops back this morning 
through the afternoon across portions of NE TX/N LA which will 
remain nearly rain-free as they will not be influenced by the slow
moving shortwave trough until later in the day. Did scale back 
heavy rainfall wording to the Nrn sections of SW AR as well as 
Columbia and Union Counties into portions of NE LA, and will await
the convective trends for any further adjustments needed tonight.
Isolated convection associated with a weak seabreeze over 
portions of SW LA may only make it as far N as Cntrl LA this 
afternoon, and thus have lowered pops to slight chance/low chance 
for these areas later this afternoon. Unfortunately, the 12Z KSHV 
raob indicated a rather deep moist air mass in place which would 
not be indicative to much mixing today, especially as low level 
moisture pooling continues ahead of the weak cold pool over SW AR.
Did bump temps up a bit over N LA given the current trends as 
well as the delayed timing in the convection, with the high 
dewpoints in the mid 70s resulting in heat indices near 105 this 
afternoon over this area. 

Zone update already out...grids will be available shortly. 

15

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  94  73  86  71 /  30  70  70  60 
MLU  93  72  84  71 /  60  70  70  60 
DEQ  87  70  87  69 /  70  60  50  30 
TXK  90  73  86  72 /  60  70  70  40 
ELD  90  71  85  68 /  70  70  60  50 
TYR  93  75  88  71 /  20  50  70  60 
GGG  92  74  87  71 /  20  50  70  60 
LFK  94  75  90  72 /  20  20  70  60 

&&

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

$$

15