346
FXUS64 KSHV 221558
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
1058 AM CDT Wed May 22 2024

...New UPDATE...

.UPDATE...
Issued at 1027 AM CDT Wed May 22 2024

Severe Thunderstorm Watch Number 284 will be in effect until 500
PM CDT for southeast Oklahoma and adjacent portions of northeast
Texas and southwest Arkansas, with southern and eastward expansion
likely later today.

Strong areas of convection have begun to light up across eastern
Oklahoma as of the 15Z hour and do not show any signs of weakening
as they trek south and east into the ArkLaTex. The southernmost
of these cells is approaching Pushmataha and Choctaw counties and
looks to begin impacting McCurtain county Oklahoma within an hour
or two.

This development is representative of a somewhat earlier
progression of today`s severe weather than the latest model runs
suggested, but the ultimate mode of convection appears
consistent. Additional discrete development pushing out of central
Texas later today is possible, followed by coalescing into an MCS
as the event progresses. Large hail in excess of 2 inches in
diameter and damaging severe wind gusts will be the primary
threats associated with these storms, but a tornado or two cannot
be ruled out.

Increased PoPs across our northernmost zones to represent this
accelerated arrival of storms, and based on yesterday`s highs
despite cloud cover, nudged today`s highs up a degree or two.
Ingested the most recent several hours of temperature and dewpoint
observations and interpolated through to 00Z Thursday.

/26/

&&

.SHORT TERM...
(Today through Thursday Night)
Issued at 205 AM CDT Wed May 22 2024

Tricky short term forecast as there have been some changes with
the 00z progs that will result in the heavier rain threat shifting
further south towards the I-20 Corridor if these latest trends end
up verifying.

Currently dealing with widely scattered showers and thunderstorms
across portions of SE OK and SW AR along remnant outflow boundary
and a weak perturbation that moved out of the Ouachitas earlier
Tue Evng. Plentiful mid and high level cloud cover, not to mention
returning low cloud cover and a tight surface pressure gradient
is resulting in very warm predawn temperatures still near 80
degrees in a few locations. Meanwhile, the true cold front remains
across NW AR into Eastern and Central OK attm with this feature
forecast to move a little further south, perhaps in the
Upper/Middle Red River Valley by 00z this evening.

The setup today for renewed convection remains the same. Upper
flow remains from the WSW and ripples in this flow will interact
with extreme instability today to produce intense convection, some
of which will produce damaging thunderstorm wind gusts and large
hail, especially if an MCS can materialize off the stalled frontal
boundary and move into our region as some of the latest CAMS and
deterministic progs suggest. There will be plenty of CAPE and Deep
Layer shear to suggest that supercell thunderstorms will also be
possible and with lapse rates near 8 deg in the 700-500mb layer,
hail larger than 2 inches in diameter will also be possible. While
an isolated tornado cannot be ruled out initially with any
discrete supercell thunderstorm or embedded in any QLCS segments,
the tornado probability is a distant third risk compared to the
wind and hail risks through tonight.

As mentioned above assuming this MCS does develop, it`s movement
will be more likely to the southeast vs east (per previous
deterministic model runs) which suggest the heavier rain threat
may be further south through tonight or closer to the I-20
Corridor than the I-30 Corridor. Regardless, rainfall amounts of
1-3 inches will be possible which we should be able to take
without much in the way of any widespread flooding concerns.
Therefore a Flood Watch will not be necessary with this forecast
package.

Given the uncertainty with the first 24hrs of convective evolution
across our region, this opens up even more uncertainty pertaining
to the Thu/Thu Night forecast when it comes to additional
severe/heavy rain potential. A lot of this potential will be based
on where outflow boundaries will be present and the capability of
atmospheric recovery during the day Thursday. Much of the first
half of Thu looks fairly uneventful until we see afternoon,
diurnally driven instability once again. Upstream disturbances
will quickly move out of the TX Hill Country and into the Middle
Red River Valley for another chance for strong to severe
thunderstorms, this time mainly across our northwest half. Again,
large hail and damaging thunderstorm wind gusts along with heavy
downpours will accompany the late Thu/Thu Night event per SPC and
WPC`s Slight Convective Risk and Slight Excessive Rainfall
Outlooks.

13

&&

.LONG TERM...
(Friday through Tuesday)
Issued at 205 AM CDT Wed May 22 2024

Much of Friday looks quiet, except by late afternoon into the
evening and overnight hours when strong to severe thunderstorms
could redevelop along the old frontal boundary which may be
located across SE OK into SW AR and NE TX. Extreme instability
and steep mid-level lapse rates would again promote large hail and
damaging thunderstorm wind gusts and the same could be said for
late Sat Aftn/Sat Night across the same general areas.

Held onto small pops across our northern and northeastern zones
for Sunday/Sunday Night and areawide Monday/Monday Night that will
come with an apparent frontal passage. This frontal passage is
setup by a change in the overall upper level pattern with upper
ridging across the Intermountain West and a longwave trough
swinging through the Plains.

Ahead of the frontal boundary, some of the hottest temperatures
of the late Spring Season will be felt across our region Sat and
again on Sunday with afternoon high temperatures in the middle 90s
across much of the region. Combine this with high afternoon
humidity values and Heat Indices will come dangerously close to
Heat Advisory Criteria of 105 degrees, especially on Sunday.

13

&&

.AVIATION...
(12Z TAFS)
Issued at 643 AM CDT Wed May 22 2024

Scattered instances of MVFR flight conditions will persist for the
first few hours of the period but an improvement into the VFR
range is expected in most locations by midday. However, scattered
showers and thunderstorms should begin to develop by early
afternoon and will rapidly increase in coverage and intensity
after 22/19z and should eventually affect all TAF sites by 23/04z.
The convection may diminish very late in the period, but may
still be ongoing across Southeast Oklahoma, Northeast Texas, and
Southwest Arkansas including KTXK and KELD.

CN

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  93  74  91  74 /  50  70  20  20
MLU  92  72  90  72 /  40  60  20  20
DEQ  88  67  82  67 /  90  70  50  50
TXK  92  71  88  72 /  90  70  40  40
ELD  91  68  87  68 /  80  60  30  30
TYR  92  73  89  73 /  60  70  20  20
GGG  93  72  90  72 /  50  70  20  20
LFK  91  73  92  74 /  20  50  20  20

&&

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

$$

SHORT TERM...26
LONG TERM....13
AVIATION...09