092
FXUS64 KSHV 130232
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
932 PM CDT Sun May 12 2024

...New UPDATE...

.UPDATE...
Issued at 923 PM CDT Sun May 12 2024

We continue to deal with widespread showers with embedded
thunderstorms near and north of the I-20 Corridor across N LA
which includes most of SW AR with the more intense convection with
higher rainfall rates noted across Deep East Texas into portions
of West Central Louisiana. This area resides under a higher 850mb
theta-e gradient augmented by a near 30-40kt low level jet and
thus it would make since that the higher rainfall rates were
located across the general area. As we move through the remainder
of the overnight hours, feel like we will begin to lose this
augmentation as low level winds veer around to more of a WSW
direction with speeds coming down and latest HIRES solutions do
indicate not quite the coverage or intensity as we move towards
the predawn hours. Until then, flooding will continue to be a
concern across our far southern zones.

Concerning temperatures, 02z temps were already at or below
forecast min temps so did need to lower temps slightly to account
for this. Other changes included some dewpoint changes to account
for current and forecast trends as well as some changes to sky
grids.

Updated forecast package has been sent...13.

&&

.SHORT TERM...
(This evening through Monday Night)
Issued at 332 PM CDT Sun May 12 2024

The afternoon sfc analysis indicates a warm front that extends
from near LCH W to just N of IAH to just S of CLL and ATT as of
1930Z, with only a slightly Nwd jog of this bndry noted since this
morning. With the convection having become widespread N of the
bndry across much of Cntrl/N TX into Nrn, Cntrl, and SW LA, the
rain cooled air should not allow for much Nwd return this evening,
until the convection begins to diminish later this evening as
drier mid level air over far W TX begins to entrain E across N TX
ahead of upper troughing that will drift E into Wrn/Cntrl KS and
the TX Panhandle. While the severe threat has diminished slightly
since this morning, still seeing a narrow swath of deeper
convection still ongoing from Houston County TX SE through Srn
Cherokee, Nacogdoches, Angelina, and San Augustine Counties,
associated with stronger convergence along an H850 inverted trough
extending from Cntrl TX SE into Deep E TX/SW LA. This bndry is
progged to lift N through E TX/N LA this evening, which would
focus the greater potential for heavier rainfall before weakening
overnight. The greater rainfall amounts have been largely focused
across Angelina, San Augustine, and Sabine Counties in Deep E TX,
with totals ranging from 1.25 to 2.00+ inches, with additional
amounts of 1-3 inches possible across the Flood Watch area through
Monday evening. Left the Watch area as is, but did add Grant and
La Salle Parishes as the various CAMs suggest that some of the
higher totals potentially affecting this area tonight.

After the break in the convection later tonight, will have to
await for the primary upper trough axis to rotate through the Red
River Valley Monday, which will reinforce a weak cold front SE
into Ern OK/Nrn and Cntrl TX during the afternoon. Large scale
forcing is expected to increase especially from midday through the
afternoon, with some insolation resulting in increased sfc-based
instability accompanied by steep lapse rates aloft, with a
potential MCS developing as it shifts ESE across E TX/portions of N
LA. Large hail and damaging winds will be possible across these
areas, with a renewed threat for heavy rainfall as it spreads SE
across the Flood Watch area. This convection should diminish
during the evening, with the potential for the Watch area to be
cancelled early as drier and more stable air spreads SE in wake of
the weak cold fropa.

15

&&

.LONG TERM...
(Monday night through next Saturday)
Issued at 332 PM CDT Sun May 12 2024

A brief drying trend is in the offing Tuesday and Wednesday in
wake of the fropa, with near normal temps and slightly lower RH`s
expected. Weak upper ridging is progged to build E over the region
during this time, before a SW flow aloft commences ahead of
troughing that will develop from the Great Basin into the Rockies,
absorbing a weak closed low over Srn CA/Nrn Baja. Shortwave energy
ejecting NE ahead of this trough will yield increasing convection
across TX Thursday where a more substantial increase in low level
moisture will be, with pieces of this convection eventually
spreading E into the region during the day. Any severe potential
will be largely dictated any return instability that develops as
the deeper low level moisture will be a bit slower to arrive,
before the primary trough itself arrives Thursday night resulting
in more numerous and potentially deeper convection. This trough
may result in this weak sfc front to drift SE through the area
Friday afternoon/night, but remains largely uncertain whether it
will have enough momentum to exit the area, or possible stall over
E TX/N LA and thus maintain unsettled weather as we move into next
weekend.

15

&&

.AVIATION...
(00Z TAFS)
Issued at 633 PM CDT Sun May 12 2024

Widespread rain with embedded thunderstorms will taper to showers
and isolated thunderstorms late this evening, with a short break
in the wet weather likely for most terminals early Monday morning.
Ceilings at the 00z TAF issuance are generally VFR, with some
areas of IFR across western terminals in TX. Confidence is high in
ceilings lowering to widespread IFR after midnight and continuing
through Monday morning, with some LIFR possible along with
fog/drizzle and reduced vsbys. Some recovery back to MVFR is
probable late morning into early afternoon as the next round of
convection develops and moves west to east through the afternoon.
Winds S/SE through about 18z Monday before shifting slightly S/SW
in the afternoon 8-10kts. Winds locally gusty and erratic in
direction temporarily during any passage of a thunderstorm thru
the TAF period.

Kovacik

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  65  83  65  84 / 100  50  30   0
MLU  63  82  65  85 / 100  60  50  10
DEQ  61  79  59  82 /  70  40  20  10
TXK  62  80  62  83 /  70  40  20  10
ELD  61  79  62  82 / 100  40  40  10
TYR  64  83  62  84 /  60  40  10   0
GGG  63  83  63  84 /  60  40  20   0
LFK  65  85  65  87 / 100  50  20   0

&&

.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...Flood Watch through Tuesday morning for LAZ001-002-010-011-017-
     018-020-022.

OK...None.
TX...Flood Watch through Tuesday morning for TXZ124>126-136>138-
     149>153-165>167.

&&

$$

SHORT TERM...15
LONG TERM....15
AVIATION...23