533
FXUS64 KSHV 080815
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
315 AM CDT Wed May 8 2024

...New SHORT TERM, LONG TERM...

.SHORT TERM...
(Wednesday through Thursday)
Issued at 258 AM CDT Wed May 8 2024

Key Messages:

- Multi-day severe weather threat across the Ark-La-Tex starting
this afternoon, through late Thursday night/early Friday morning.

- All modes of severe weather will be possible during this period,
with specific focus on the threat for large hail and damaging wind.

Wednesday-Thursday Morning:

Morning surface observations across the Four State Region depict a
lifting warm front across the I-30 corridor, supporting an expansive
warm sector for deeply rooted convection later this afternoon as
frontal based lift, associated with a trailing surface cold front,
works across the Southern Plains and into SE Oklahoma, and NE Texas.

In the aforementioned warm sector, a volatile environment will
prevail as maxT`s climb into the upper 80`s and low 90`s once again
this afternoon. Model guidance continues to impress as suggested
SBCAPE profiles of 4000 J/kg and greater will exist across much of
the Ark-La-Tex. Meanwhile, steep 700-500 lapse rates of 8.0 C/km
coexist in a region of moderate deep-layer shear. Given the
parameters in place, once initiation does occur, the threat for a
few discrete supercells supporting the threat of large hail and
damaging wind will be possible within the severe primed
environment across portions of NE Texas, SE Oklahoma, and SW
Arkansas. Not ruling out the chance for a tornado with any
developing supercells, but this remains conditional at this time.
As expressed in previous AFD`s leading up to today, convective
coverage remains rather uncertain and will likely be this way up
until initiation is seen later this afternoon.

By the evening, what does evolve should begin to form into a linear
storm mode where damaging winds, hail and a conditional embedded
tornado threat will exist. There remains some uncertainty how long
and how expansive this linear storm mode is before decaying.
Model guidance this morning suggests that the proposed linear
storm mode collapses as it works into portions of NW Louisiana.
For now though, messaging remains the same with the idea that
severe storms will be possible through the mid to late evening.

Given the severe threat in place this afternoon, an Enhanced risk
(level 3 of 5) exists across the I-30 corridor, with a Slight risk
(level 2 of 5) south through I-20. This outlook could change in
future updates if confidence increases with incoming guidance
through the morning.

Thursday-Thursday Night:

By Thursday morning, the cold front from Wednesday should be located
somewhere between the I-30 and and I-20 corridor, slowly advancing
southward through the afternoon. Along and ahead of the front, a
moisture rich environment will exist, with another primed layer of
very generous surface instability and modest deep layer shear for
thunderstorms to thrive in if allowed the opportunity to do so.

Given the slow southward progression of the front, elected to
increase maxT`s along the I-20 corridor and south, citing the chance
for some compressional warming before thunderstorms develop once
again across central Texas by the mid to late afternoon. These may
spread eastward by the evening in the form of a possible multi-
cell complex where damaging wind and hail will be the primary
threats. This should clear the area by early Friday morning.

Given the forecast axis of heavy rainfall along the I-20 corridor
and south, a Slight risk of excessive rainfall is being advertised
valid 12z Thursday, through 12z Friday. At this time, WPC 3 day QPF
values in this region suggest a possible 1-2", not counting the
chance for any locally higher amounts.

RK

&&

.LONG TERM...
(Thursday Night through Wednesday)
Issued at 258 AM CDT Wed May 8 2024

The front will be well south of the FA by mid-Friday morning with
high pressure settling in behind. Influence of the passing
boundary, and high pressure will promote drier conditions through
the end of the week and heading in the weekend, with a return to
near normal temperatures. Rain chances return through Sunday as
shortwave pertubations within the mid-level flow work across
Texas and Louisiana.

To no suprise, and being this this far out, there remains some
uncertainty on where the axis of the heaviest rainfall will set up.
That being said, rain chance do return by the end of the weekend
into early next week. At the same time, maxT`s will gradually climb
back through the low to mid 80`s through the end of the period.
Overnight lows will follow a similar trend, climbing through the mid
to upper 60`s.

RK

&&

.AVIATION...
(06Z TAFS)
Issued at 1158 PM CDT Tue May 7 2024

MVFR ceilings rapidly returning attm across our airspace and
should see these conditions prevailing by the next 2-4 hours.
Added VCTS to the TYR/TXK terminals for the next 2-4 hours given
convective trends with a weak boundary in place. Otherwise, should
see MVFR ceilings climb to low VFR variety by late morning into
the afternoon before scattering out all together by late
afternoon. Introduced VCTS at the TYR/GGG/TXK and SHV terminals
this evening with scattered strong to severe convection expected
to develop along the same boundary towards the tail end of the
06z TAF period. Stronger pressure gradient in place today will
result in stronger S winds today with sustained winds near
10-14kts with gusts upwards of 25kts beginning after sunrise
towards mid morning and continuing through the day.

13

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  93  73  88  66 /  20  30  30  50
MLU  92  72  90  66 /  10  30  20  50
DEQ  85  62  83  58 /  40  70  30  20
TXK  92  69  86  62 /  30  70  30  30
ELD  90  66  86  61 /  10  50  30  40
TYR  90  72  87  63 /  20  20  40  40
GGG  90  70  87  64 /  20  30  30  40
LFK  90  73  92  66 /  10  10  20  40

&&

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

$$

SHORT TERM...53
LONG TERM....53
AVIATION...13