753
FXUS64 KSHV 050537
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
1237 AM CDT Sun May 5 2024

...New AVIATION...

.UPDATE...
Issued at 1033 PM CDT Sat May 4 2024

Not much change from previous forecast for this evening into the
overnight hours. A large complex of showers and thunderstorms have
formed across portions of West and North-Central Texas. The HRRR,
which seems to have a good handle on this set-up, continues to
suggest this complex will form into a MCS and shift eastward
towards the region during the overnight hours. Can`t rule out an
isolated strong to severe thunderstorm, with damaging winds and
large hail being the primary threat. Moderate to heavy rainfall
can also be expected. Although WPC has a Moderate Risk for
excessive rainfall across portions of Deep East Texas and a Slight
Risk for a large portion of the region, decided to hold off on a
Flash Flood watch at this time. RFC Flash Flood Guidance suggest
we can handle the expected amount of QPF, but this will need to
be monitored closely. Otherwise, expect overnight lows in the mid
to upper 60s. /20/

&&

.SHORT TERM...
(This evening through Sunday Night)
Issued at 310 PM CDT Sat May 4 2024

A few showers and thunderstorms will persist through early this
evening, mainly across portions of Angelina, San Augustine, and
Sabine Counties along a stalled surface boundary. Most of the
heavier storms should remain south of the CWA. Farther north, more
isolated convection associated with a shortwave trough approaching
the Mississippi River should exit the area by early this evening.
In fact, most of the ongoing precip should end by sunset. However,
this break will only be temporary.

Another complex of strong to severe thunderstorms is expected to
develop across West Texas this evening and tonight as the next
shortwave trough strengthens while ejecting northeast across Texas
and towards the ArkLaTex. The HRRR and HREF have tended to perform
the best over the last couple of days, so this forecast more
closely follows those models versus the NAM, GFS, and ECMWF. This
is also results and earlier time of arrival of the leading edge
of the storms into Southeast Oklahoma and East Texas, which should
be between 05z-09z (midnight-4 AM CDT)tonight/Sunday morning. This
complex should weaken somewhat with eastward extent across the
forecast area Sunday morning, but an isolated severe weather
threat cannot be ruled out. Damaging winds and large hail should
be the main threat.

The forecast becomes more uncertain after mid to late Sunday
morning. The HRRR suggests a notable lack of convection across
most of the CWA with the exception of the far northern and far
southern zones, probably because the atmosphere should be worked
over. However, there may be some recovery during the day, which
should allow for renewed, and likely more scattered development.
This is most likely across Southeast Oklahoma, Southwest Arkansas,
and Northeast Texas where lift will be maximized with the
shortwave trough. Farther south, a series of thunderstorms
complexes with the potential to produce locally heavy rain is
possible as a secondary wave in the flow aloft moves across
Southeast Texas. Current thinking is that most of this convection
should remain just south of the CWA. It is somewhat concerning,
and worth noting, that the NAM brings this heavy rain threat into
Deep East Texas Sunday afternoon, which would increase the risk
for flooding.

There is a moderate risk for excessive rainfall in portions of
Deep East Texas on Sunday per WPC. For our area, this appears to
be associated mainly with the morning convection. While locally
heavy rain is possible, the risk for flooding is expected to be
short-lived and localized at this time, especially as compared to
areas just south and southwest. Therefore, we opted to forego
issuing a Flood Watch. Overall, an additional 1 to 3 inches of
rainfall, with locally higher amounts, are possible through
Sunday evening in Deep East Texas.

Rain chances should finally diminish from southwest to northeast
Sunday night and early Monday morning.

CN

&&

.LONG TERM...
(Monday through next Friday)
Issued at 310 PM CDT Sat May 4 2024

Strong southwesterly flow aloft associated with a powerful upper
low across the Northern Plains combined with a deep low-level
southerly flow will keep a rather abundant pool of moisture
throughout the atmospheric column. With a cold front northwest of
the area, this will keep near daily chances for scattered
convection in the forecast for much of next week. Sufficient
instability and deep layer shear will also result in at least some
threat for severe storms each day. The highest rain chances and
corresponding chances for severe weather should be Wednesday and
possibly into Thursday as a cold front finally approaches and
moves across the area. The greatest coverage and best rain chances
can be expected in the afternoons and evenings.

Surface ridging should finally build into the area by Friday and
into Saturday providing enough subsidence and dry air advection to
bring most of our rain chances to an end. While the deterministic
GFS and ECMWF remove all chances for rain, the ensembles and the
NBM still keep some light QPF and slight chances for rain in the
forecast as one more shortwave trough dives south along the
Mississippi River to start the weekend.

With the strong southerly surface flow at the beginning of the
week, strong warm air advection can also be expected. With showers
and thunderstorms being more of a scattered nature, temperatures
will be able to climb ever upwards. Confidence continues to
increase regarding unseasonably high temperatures, especially next
Tuesday through Thursday. NBM probabilities of high temperatures
of at least 90 deg F are now on the order of 80 to 90 percent in
some portions of Louisiana by Wednesday. With peak heat index
values near the century mark, the hot and humid conditions will be
more typical of mid June versus early May.

CN

&&

.AVIATION...
(06Z TAFS)
Issued at 1224 AM CDT Sun May 5 2024

Convection continues to expand in coverage just west of the
airspace tonight, and will start to impact the western terminals
within the next hour before impacting all terminals later this
morning. Given the close proximity to GGG, TYR and LFK, have added
a TEMPO group for TSRA at these terminals through the first few
hours of the TAF period. Not expecting TSRA airspace wide, but
more SHRA coverage through much of the period before some clearing
later this afternoon. Still some uncertainty on redevelopment of
SHRA/TSRA later this afternoon. Latest CAMs suggest a few pop up
showers, maybe some isolated TSRA. For now, elected to add some
VCSH for most around 00z. Plan is to continue monitoring trends
and reevaluate later this morning.

RK

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  79  68  85  74 / 100  30  40   0
MLU  80  66  86  70 /  60  40  40   0
DEQ  73  63  80  67 / 100  30  30  20
TXK  75  66  84  71 / 100  40  40  10
ELD  76  63  83  68 /  80  40  40  10
TYR  79  68  85  72 /  80  20  20   0
GGG  78  67  84  71 / 100  20  30   0
LFK  80  68  86  71 / 100  10  20   0

&&

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

$$

SHORT TERM...09
LONG TERM....09
AVIATION...53