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000
FXUS64 KSHV 182054 AAA
AFDSHV

Area Forecast Discussion...UPDATED
National Weather Service Shreveport LA
354 PM CDT Thu Apr 18 2024

...New UPDATE...

.UPDATE...
Issued at 354 PM CDT Thu Apr 18 2024

Zone update just sent to account for SVR Watch #126 that is in
effect through 04Z this evening for McCurtain County OK and the
Nrn sections of SW AR. This threat remains conditional and
primarily frontal driven within the very moist and unstable air
mass in place, and given the lack of strong overall forcing
aloft, is expected to diminish later this evening with reduced
heating/instability.

15

&&

.SHORT TERM...
(This evening through Friday Night)
Issued at 139 PM CDT Thu Apr 18 2024

Interesting atmospheric profile across our region attm as
temperatures continue warming into the 80s across most areas with
dewpoints in the lower 70s resulting in SBCAPE values approaching
3000 J/KG. Mid-level lapse rates near 7-7.5 J/KG are present attm
as well with Deep Layer Bulk Shear values near 40kts which
suggests the possibility of organized warm sector severe
convection with large hail and damaging thunderstorm wind gusts
the primary threats this afternoon across portions of Northeast
Texas, Northern Louisiana and South Central Arkansas. The one
thing lacking and it`s a pretty big thing is upper level forcing
but we do introduce this into the mix in advance of a strong cold
front later this evening along and near the I-30 Corridor. The
shortwave is subtle but may be enough to generate strong to severe
thunderstorms across our northwest half through the evening
hours.

The severe weather threat along with pop coverage should diminish
greatly after midnight but the cold front will continue to slowly
move into our region through the night from the northwest and
should be near a LFK to SHV to ELD line by 12z Fri. The front
should slow its southward progression during the day Friday but
held onto slight chance pops areawide on Friday as post frontal
precipitation definitely cannot be ruled out while coverage will
be lacking. We middle away the 80s for highs on Friday behind the
cold front along and north of the I-20 Corridor with lower to
middle 80s confined to our southeast half in advance of the cold
front.

By Friday Night, upper forcing will begin to intrude once again
from the west in advance of another weak trough and while there
will be no surface warm sector to speak of, ascent in advance of
this subtle shortwave will result in scattered to numerous showers
and thunderstorms once again late Friday Night, mainly across our
northwest half as the remainder of our region awaits widespread
rainfall Saturday into Saturday Night. More on this with the long
term discussion below.

13

&&

.LONG TERM...
(Saturday through next Wednesday)
Issued at 139 PM CDT Thu Apr 18 2024

Upstream, upper flow becomes WSW during the day Saturday in
advance of an upper level trough which moves out of the Big Bend
area of Texas Sat Aftn quickly ejecting out across our region
overnight Saturday Night, pivoting east of our region during the
day Sunday. Southerly low level flow will overrun northeasterly
flow at the surface and you have the ingredients for elevated
convection during this timeframe. PWATS in the neighborhood of
1.5+ inches suggests that there will be a potential for heavy
rainfall, especially Saturday Night as the 850mb frontal boundary
lags the sfc boundary by a significant margin. Looking for
widespread one to three rainfall amounts late Friday Night through
early Sunday with isolated higher amounts which may result in
renewed flooding on area waterways not to mention poor drainage
and flood prone areas. Post upper trough temperatures for highs on
Sunday should only max out in the 60s which will be quite the
change from what we`ve experienced lately but temperatures will
quickly moderate as we move into the upcoming work week.

Reintroduced small pops back into the forecast for Tue Night into
Wed but confidence is not high on this with upstream upper ridging
across the Foothills of the Rockies but something more supportive
of higher pops appears to be just outside this 7-day forecast
window as our next longwave trough takes shape across the
Intermountain West.

13

&&

.AVIATION...
(18Z TAFS)
Issued at 1213 PM CDT Thu Apr 18 2024

Complicated forecast for the 18/18z TAF period as there remains
much uncertainty surrounding TSRA development along an approaching
cold front this afternoon, and its impact on area terminals.
Satellite this afternoon promotes mass coverage of dense overcast,
especially at the lower levels (sub FL100). At the same time, an
axis of forcing has supported TSRA/SHRA in a line from KLFK to
KELD. Latest guidance continues to suggest this will increase in
coverage through the afternoon. As a result, elected to TEMPO in
TSRA along many of the I-20 terminals through the first few hours
of the period.

Beyond 00z, as the cold front works across East Texas, additional
thunderstorm development looks to prevail and potentially impact
terminals from KTYR to KTXK, collapsing the further east the
convection travels. TSRA has been added to adjust for this
convective evolution this evening. Guidance suggest the majority
of what does develop should conclude shortly after 06z. This will
then be replaced by low CIGs and reduced VSBY as moisture pooling
ahead of the front supports BR through 12z Friday. Confidence in
flight conditions recovering more than IFR is not high at this
time. Much of this will depend on just how far south the front
advances prior to 18z Friday.

RK

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  65  77  60  67 /  30  20  40  60
MLU  66  77  59  66 /  20  20  20  50
DEQ  54  71  50  59 /  50  20  70  80
TXK  60  71  53  61 /  50  20  60  80
ELD  61  70  51  61 /  40  20  40  70
TYR  61  74  60  67 /  40  20  50  80
GGG  61  75  59  67 /  40  20  40  70
LFK  66  84  66  79 /  20  20  10  60

&&

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

$$

SHORT TERM...15
LONG TERM....13
AVIATION...53