384
FXUS64 KSHV 211148
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
648 AM CDT Tue May 21 2024

...New AVIATION...

.SHORT TERM...
(Tuesday through Wednesday Night)
Issued at 143 AM CDT Tue May 21 2024

Tightening boundary layer pressure gradient this morning is
indicative on what we are seeing on IR Imagery currently with the
return of low level cloud cover across at least the western half
of our region. This low level warm air and moisture advection is
having an adverse effect on temps compared to 24 hours ago as
well with current ambient temperatures running some 2-6 degrees
warmer across most locations.

Upper level ridging is still firmly in place this morning from SE
TX through our region and into the Tenn Valley but this feature
will edge eastward today, allowing for more in the way of
southwesterly flow aloft upstream across the Middle Red River
Valley of NE TX, SE OK and SW AR by this evening into the
overnight hours. Shortwave energy will likely remain locked up
well north of our region but there could be enough forcing across
E OK into far NE TX to support some strong to severe convection by
this evening. Convective initiation today will be highly
conditional on a strong capping inversion being broken later today
and if that can materialize, then initiation will likely take
place north northwest of our far northwest zones with the
possibility of some of this convection moving into our far
northwest zones during the evening and overnight hours. CAMS are
split on this outcome and with SPC`s SLGT Risk for severe
convection across our far northwest zones late today/overnight,
cannot rule out the possibility of large hail and damaging wind
gusts, again, if the CAP can be broken and we can see any upstream
convection move into our region. My only pops today through 7pm
are across far northwest McCurtain County, OK and only of the
Slight Chance variety. Pops only expand in coverage to encompass
NE TX, SE OK and SW AR, mainly this evening and in the low end
chance variety given the uncertainties mentioned above.

By Wed, we will have lost any influence of the upper ridging to
our east as southwest flow aloft only increases upstream from the
TX Hill Country and into the Middle Red River Valley. There will
be at least two disturbances in this flow that we will need to be
alert to. The first possibly influencing our northwest third
during the morning hours on Wed and another by very late in the
afternoon and into the evening hours Wed Night. CAMS remain split
on these outcomes as well with some not even acknowledging the
first disturbance but most focusing on the second disturbance.
Likewise, SPC has outlooked most of our region near and northwest
of the I-30 Corridor in an ENH Risk for severe thunderstorms on
Wed/Wed Night and this looks mostly tied to a wind/hail threat.
Capping does not appear to be an issue on Wed compared to today
so pops for Wed have been adjusted upward to likely categories
near and northwest of the I-30 Corridor with low end chance
variety as far south as the I-20 Corridor of NE TX into N LA.

13

&&

.LONG TERM...
(Thursday through Tuesday)
Issued at 143 AM CDT Tue May 21 2024

Thursday`s convective development will be tied to just what kind
of boundaries we are left over with from Wed/Wed Night`s
convection, not to mention residual disturbances in a stout WSW
flow aloft regime. Given the upstream forcing in the
deterministic models, again, capping should not be an issue and
instability appears to be near to that we should see on Wednesday
with damaging wind gusts and large hail the main threats once
again. It does appear that the true cold front should remain just
to our northwest on Thu with this feature returning back
northward Thu into Thu Night. In addition to the severe weather
threat Thu, we will need to watch for an excessive heavy rainfall
threat as well but that will greatly depend on just how much
rainfall our northwest half sees Wed into Wed Night. Over the last
two weeks, it`s been our northwest and northern zones that have
not seen near the rainfall amounts our southern half has seen and
thus, as long at the rainfall does not become too excessive near
and northwest of the I-30 Corridor Wed/Wed Night, we should be
able to take the additional rainfall across our northwest half on
Thu without too much in the way of widespread flooding impacts.

Pivoting to Friday and the upcoming Memorial Holiday Weekend,
deterministic models are in pretty good agreement without too
much in the way of widespread precipitation chances, instead,
slight chance/low end chance variety pops will be tied to diurnal
heating. Having said that, the upper flow pattern will remain west
southwesterly and thus, the pop forecast confidence remains a low
one for the upcoming weekend into Memorial Day. One thing that is
a little more certain is the weekend heat with high temperatures
likely in the middle 90s at least near and south of the I-20
Corridor with heat indices well into the triple digits but just
under Heat Advisory Criteria of 105 degrees.

There still appears to be a pattern shift beyond Memorial Day next
week as upper ridging appears to become dominate across the
Intermountain West with troughing developing across the Great
Lakes, into the Ohio and Tenn Valleys. This should result in a
cooler pattern for our region with a frontal passage sometime on
Memorial Day or into Monday Night with obviously chance pops tied
to the front itself.

13

&&

.AVIATION...
(12Z TAFS)
Issued at 639 AM CDT Tue May 21 2024

Low clouds and MVFR ceilings will persist across portions of East
Texas and Western Louisiana along and south of Interstate 20 for
the first few hours of the TAF period. However, flight conditions
should gradually improve back into the VFR range before 21/18z.
More low clouds and MVFR/IFR flight conditions are expected to
rapidly spread across the region during the after 22/04z, likely
affecting most TAF sites. Scattered showers and thunderstorms may
also affect Southeast Oklahoma and portions of Northeast Texas and
Southwest Arkansas in the 21/23z-22/06z time frame. KTXK and KTYR
are the most likely TAF sites to be affected, but confidence is
currently too low to mention thunderstorms in the TAFs.

CN

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  93  77  91  74 /   0  10  20  30
MLU  92  73  89  71 /   0  10  20  20
DEQ  89  71  85  67 /  10  30  70  70
TXK  92  75  90  70 /  10  20  60  60
ELD  91  73  88  68 /   0  10  40  40
TYR  91  76  90  73 /  10  20  30  30
GGG  91  76  90  73 /  10  20  20  30
LFK  91  76  90  73 /  10  10  10  10

&&

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

$$

SHORT TERM...13
LONG TERM....13
AVIATION...09