689
FXUS64 KSHV 081610
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
1110 AM CDT Wed May 8 2024

...New UPDATE...

.UPDATE...
Issued at 1041 AM CDT Wed May 8 2024

As of 10:45 AM today, temperatures are reaching the lower 80s
once again under mostly cloudy skies. Later this afternoon and
going through the evening, severe thunderstorms capable of
producing large hail and/or damaging winds are likely to develop,
especially along and north of the I-30 corridor. Otherwise, temperature
maximums will be above average in the lower 90s. With weather and
observed trends continuing as anticipated, forecast grid
adjustments were not necessary at this time. /16/

&&

.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 perturbations within the mid-level flow work across
Texas and Louisiana.

To no surprise, 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...
(12Z TAFS)
Issued at 455 AM CDT Wed May 8 2024

MVFR ceilings prevailing attm across most all our airspace. Look
for these ceilings to lift by mid to late morning. Strong pressure
gradient in place will result in sustained SSW winds near 10-14kts
with gusts upwards of 25kts possible, especially across our NE TX
terminal locations. Ceilings may briefly mix out all together but
later this evening, look for convection to develop and/or move
into our NE TX terminals, mainly north of the LFK terminal but
it`s impacts will likely be felt at the TXK and SHV terminals as
well. Convection should be weakening as it moves into the eastern
half of our airspace after midnight so left mention out of the LFK
and MLU terminals. Look for a return to MVFR ceilings once again
outside of and after the convection dissipates or closer to
sunrise Thursday Morning.

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...16
LONG TERM....16
AVIATION...13