818
FXUS64 KSHV 281745
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
1245 PM CDT Sun Apr 28 2024

...New AVIATION...

.UPDATE...
Issued at 1134 AM CDT Sun Apr 28 2024

A busy afternoon and evening remain on tap for the Four State
Region, we still anticipate convection developing across the
region ahead of an approaching trough/cold front. Wind and hail
remain the primary threats, but can`t rule out a few tornadoes as
well along with possible flash flooding. For this update, decided
to add slight POPS to the entire region for the remainder of the
day, as isolated convection is started to develop areawide. Also,
adjusted the temps based on current and forecasted trends.
Otherwise, the remainder of today`s forecast package remains on
track.

/20/

&&

.SHORT TERM...
(Sunday through Monday)
Issued at 424 AM CDT Sun Apr 28 2024

The early morning water vapor imagery indicates a neutral tilt
upper trough extending from Wrn NE S through Wrn KS into far W TX
into Srn NM, with a line of strong to severe convection
continuing to march E into SE OK and N TX, into the Wrn Hill
Country. While these storms have shown a slow weakening trend in
the last hour or so, a large cold pool has progressed E along this
line of deep convection, resulting in strong winds gusts of
30-40+ kts especially over Srn OK into N TX. Strong convergence
along this bndry (courtesy of SE winds 10-20kts with gusts to
25-30kts) should maintain the intensity of these storms for at
least the next few hours, although a weakening pressure gradient
and gradually increasing stability over E TX/SW AR/NW LA should
result in a weakening trend after daybreak, especially as large
scale ascent also weakens as it moves farther away from the
trough.

This MCS/cold pool should leave behind a bndry later this morning
somewhere over NE TX into SW AR, with the stabilizing air mass
eventually destabilizing in response to strong heating by mid
afternoon once the upper trough axis begins to take on a negative
tilt over the Srn Plains, thus enhancing large scale ascent in VC
of the residual convective bndry. Ample shear with an area of
MLCape of 1500-2500+ J/kg will be sufficient enough for severe
convection to develop by mid and late afternoon over NE TX/SW
AR/possibly extreme SE OK, with a mostly unidirectional flow atop
the bndry lyr contributing to cell training and periods of
repeated heavy rainfall. All modes of severe weather are possible,
including isolated tornadoes embedded within the line, as some
backing of low level winds are possible just ahead of the line,
resulting in 0-1km SRH`s of 200-300+ m2/s2.

This convection may eventually develop a cold pool and allow it to
gradually progress E into Deep E TX/N LA/Scntrl AR this evening.
However, the severe and heavy rainfall/potential flood threat
will continue, with the convection eventually diminishing
overnight from the NW. The various short term progs differ
considerably with QPF late this afternoon through Monday morning,
although some general consensus of 2-4+ inches seem feasible,
with isolated higher amounts possible especially where cell
training persists. Thus, the Flood Watch will remain in effect
through Monday afternoon, although some tapering of the Watch is
expected Monday morning over the NW zones once the convection
moves out of those areas.

Much of the convection should exit Ncntrl LA by midday/early
afternoon Monday, with the resultant cold pool ushering in a
slightly drier air mass in its wake, although warm temps should
return by afternoon with the return of strong insolation.

15

&&

.LONG TERM...
(Monday Night through Sunday)
Issued at 424 AM CDT Sun Apr 28 2024

The unsettled weather pattern will continue throughout much of the
long term period as well, as the residual mesoscale bndry leftover
from Monday`s convection should eventually begin to return back N
and wash out Monday night, allowing for warmer and more humid air
to advect back N as well. Weak perturbations in the dirty zonal
flow along the returning humid air mass should help focus the
potential for scattered convection especially in the afternoon,
mainly across E TX/N LA. This convection appears to be mostly
diurnally driven, diminishing by early evening. Additional
perturbations in the flow aloft will again yield the potential for
scattered convection over much of the region Wednesday, with the
flow transitioning more to SW by Wednesday night ahead of the next
upper trough that will translate E through the Cntrl Rockies.
Thus, convection should become more numerous as the attendant
shortwave energy becomes more defined Thursday and Friday, with
likely pops expanded E across the area. Can`t rule out at least an
isolated severe threat by week`s end, all of which will be
dependent on the extent of sfc heating/resultant instability, as
well as the amplitude of these individual shortwave troughs ahead
of a weak cold front that will be reinforced into the area Friday.

Unfortunately, it doesn`t appear much cooler and drier air will
follow the fropa, with the SW flow aloft resuming next weekend
thus focusing at least isolated to scattered convection over the
region. Temps should remain near the seasonal norms by late week
into next weekend as well.

15

&&

.AVIATION...
(18Z TAFS)
Issued at 1229 PM CDT Sun Apr 28 2024

Very sloppy TAFs are anticipated over the next 24 hours, as a
strong line of showers and thunderstorms is expected to move
through the region. These storms will be capable of both very
heavy rain, and severe weather into tomorrow morning. Expect
reduced CIGS and VIS at all terminals over the next 24-hours, with
winds potentially being variable due to their convective nature.

/44/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  66  83  67  85 / 100  50  10  30
MLU  66  77  65  84 /  80 100  20  30
DEQ  61  82  58  83 /  90  10   0  10
TXK  63  83  62  85 /  90  30  10  20
ELD  63  79  60  85 / 100  70  10  20
TYR  66  84  66  84 /  80  10  10  30
GGG  66  83  65  84 /  90  20  10  30
LFK  67  86  66  86 /  90  40  10  50

&&

.SHV WATCHES/WARNINGS/ADVISORIES...
AR...Flood Watch through Monday evening for Arz070-051-059>061-
     070>073.

LA...Flood Watch through Monday evening for Lazy>006-010>014-
017>022.

OK...Flood Watch through Monday evening for OKZ077.

TX...Flood Watch through Monday evening for TXZ096-097-108>112-
     124>126-136>138-149>153-165>167.

&&

$$

SHORT TERM...15
LONG TERM....15
AVIATION...44