-- Discussion containing changed information from previous version are highlighted. --
807
FXUS64 KSHV 010957
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
457 AM CDT Wed May 1 2024

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

.SHORT TERM...
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(Wednesday through Thursday)
Issued at 457 AM CDT Wed May 1 2024

Unauthorized convection associated from two separate thunderstorm
complexes that originated over Srn and NE OK have consolidated
over portions of extreme NE TX and SE OK, and continue an ESE
movement along their respective cold pools along a narrow
instability axis over this area. The latest mesoanalysis indicates
indicates a drier and more stable air mass farther E into SW AR
and closer to the I-20 corridor of E TX, with the expectation that
this convection will continue to gradually weaken through/shortly
after daybreak, as none of the short term progs have handled the
evolution of this convection well this morning.

The morning sfc analysis also indicates a gradient of theta-e
bisecting the Wrn sections of E TX into SE TX/S LA, with this
gradient expected to gradually lift N and E later today across
portions of E TX. However, the warmer and more moist air to the W
of this bndry will quickly overtake the region tonight, as a Srly
LLJ develops ahead of a developing shortwave trough that will take
shape late this afternoon over far W TX, ahead of upper troughing
that will dig through the Nrn and Cntrl Rockies. This lead
shortwave will enhance deep convection development this afternoon
in VC of the dryline, which should eventually develop into an Ewd
propagating MCS which will surge E across the Hill County/Cntrl TX
this evening into E/SE TX overnight. The GFS remains the fastest
with the progression of this MCS, outrunning the various CAMs and
NAM, but all are in agreement that widespread rainfall amounts of
1-3+ inches are possible across much of E TX late tonight before
spreading into N LA by/after daybreak Thursday. Given the still
saturated grounds in wake of widespread heavy rain that fell
Sunday evening through Monday morning, have issued a Flood Watch
for the I-20 corridor of E TX/N LA and areas to the S from 06Z
Thursday through 00Z Friday. Because of the faster progression and
more Srly solution of the MCS via this morning`s progs vs Tuesday
morning, the earlier Moderate Day 3 ERO (from Tuesday) has fast
forwarded to the late period of the Day 1, with the Moderate Risk
focused on areas of Cntrl/SE TX which received significant
rains/flooding just a few days ago. A Slight Risk ERO remains for
much of our region though, and as long as this MCS continues this
fast Ewd progression, any flooding will be localized at best,
although additional rises on area waterways are possible.

Did maintain high end likely/categorical pops areawide Thursday,
with max temps significantly tapered back than what is expected
today, with readings well into the upper 80s or evening nearing 90
degrees. It remains to be seen though how much redevelopment will
take place in wake of the MCS passage Thursday morning, with some
of the progs suggesting additional redevelopment that will tail
back behind the MCS across portions of Deep E TX/NCntrl LA, hence
the reason why the Flood Watch was pushed out to 00Z Friday.

Thank you WFO`s FWD/HGX/LCH and WPC for your coordination this
morning.

15
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&&

.LONG TERM...
-- Changed Discussion --
(Thursday Night through Wednesday)
Issued at 457 AM CDT Wed May 1 2024

The progs continue to suggest that a weak sfc front will nudge
into portions of SE OK/SW AR and possibly extreme NE TX Thursday
night before becoming stationary, with the flow aloft again
transitioning to SW ahead of additional upper troughing from the
Pac NW into the Great Basin. Thus, perturbations in this flow as
well as the deep moisture in place will be sufficient for the
redevelopment of scattered to numerous convection ahead of the
approaching weak sfc front Thursday night and Friday. Given the
very dirty flow aloft and the progs inability to handle these
disturbances well, do not have enough confidence to push the
Flood Watch out any further, although this may be a possibility in
later forecasts. The convection may tend to become more diurnal in
nature late Friday, diminishing with the loss of heating by
Friday night, before redeveloping during the day Saturday.

Unfortunately, no change to the weather pattern/SW flow is
expected this weekend, with scattered mainly diurnal convection
continuing. However, this convection may be influenced by remnants
of upstream convection that would develop across portions of
KS/OK, which may send mesoscale bndrys SE to focus convection over
our area this weekend. SW flow aloft looks to become enhanced once
again by early next week, ahead of deep troughing that will dig
through the Four Corners Region before ejecting NE across the Srn
Rockies into the Cntrl Plains Monday. It remains to be seen
how much forcing ahead of this ejecting trough will be the
catalyst for convection over NE TX/SE OK/SW AR Monday, although
the progs remain consistent that a deeper wedge of drier air and
increased capping associated with ridging that will build from the
Lower MS Valley into the TN Valley may help to limit the extent of
convection development over much of the region. A deeper SW
unidirectional flow which also translates to the sfc by Tuesday
should yield the hottest temps so far this Spring season, with
lower 90s becoming widespread from Lower E TX across N LA,
spreading N across the remainder of the region by the end of the
forecast period Wednesday. Unfortunately, the end result given
the persistent high humidity will be heat indices topping the mid
and upper 90s by midweek next week.

15
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&&

.AVIATION...
(06Z TAFS)
Issued at 1234 AM CDT Wed May 1 2024

For the 01/06Z TAFs, VFR conditions prevail across ArkLaTex
airspace at this hour, with emerging high clouds blowing south and
east from the areas of convection in south central Oklahoma, and
otherwise SKC conditions. The presence of these high clouds may
inhibit fog development as extensive as last night`s.
Nevertheless, retaining slight VIS reductions, as shallow areas of
mist may still be possible before daybreak. VFR conditions will
otherwise continue uninterrupted aside from some lowering CIGs
during the afternoon hours. Winds will remain southeasterly
throughout, at light speeds of less than 5 kts overnight,
recovering to 5 to 10 kts sustained through the afternoon with
gusts of up to 15 kts possible.

/26/

&&

.PRELIMINARY POINT TEMPS/POPS...
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SHV  89  69  78  70 /   0  50  90  60
MLU  89  67  80  67 /   0   0  70  60
DEQ  86  64  75  63 /  30  40  90  70
TXK  88  67  77  67 /  20  40  80  70
ELD  88  66  77  65 /   0  10  80  70
TYR  88  67  80  70 /  10  80  90  60
GGG  88  68  79  69 /  10  80  90  60
LFK  89  69  81  70 /  20  80  90  50
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&&

.SHV WATCHES/WARNINGS/ADVISORIES...
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AR...None.
LA...Flood Watch from late tonight through Thursday evening for
     LAZ001>006-010>014-017>022.

OK...None.
TX...Flood Watch from late tonight through Thursday evening for
     TXZ136>138-149>153-165>167.
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&&

$$

SHORT TERM...15
LONG TERM....15
AVIATION...26