Area Forecast Discussion
Issued by NWS Shreveport, LA

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FXUS64 KSHV 241202
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
702 AM CDT Sun Mar 24 2024

...New AVIATION...

.SHORT TERM...
(Sunday through Monday)
Issued at 147 AM CDT Sun Mar 24 2024

Transition day across the Four State Region today as southeast
winds return in advance of our big weather maker late tonight and
especially on Monday. Mid and high level cloud cover already
overspreading the region attm as upper ridging begins to buckle
with a longwave trough continuing to deepen into the southwest
Great Basin. It`s a lead shortwave ejecting out of this longwave
trough this aftn/tngt that will allow for increased forcing
necessary for the development of showers and thunderstorms across
the Upper Red River Valley, eventually spreading into the Middle
Red River Valley of far NE TX/SE OK and SW AR late tonight towards
sunrise Mon Morning. At the sfc, lee-side cyclogenesis near the
OK/TX Pnhdl will deepen today...allowing for a increasingly tight
pressure gradient across our region. These increasing southeast
winds will allow for increasing low level warm air advection along
with moisture advection that will be setting the stage for the
possibility of strong to severe thunderstorms on Monday. Did not
deviate much from NBM temps or dewpoints Today through Tonight but
did adjust pops slightly across our northwest half for late
tonight.

On Monday, increasing PVA embedded in 160kt upper level jet max
extending from far SW TX through the Middle Red River Valley and
Tenn Valley will result in the increasing forcing necessary for
the development of widespread convection. The low level moisture
return will be quick with lower and middle 60 deg dewpoints
quickly moving northward into our region late tonight and into
Monday in advance of a prefrontal trough. Its this sfc trough
where this convection will develop and move from west to east
across our region during the day and into the early evening, ahead
of a strong cold front that will eventually move into our region
from the northwest late Monday Night into early Tue. Monday`s warm
sector in advance of the pre-frontal trough will be best described
as rather weak to minimal instability with MUCAPE values
generally under 1000 J/KG but very strong Deep Layer Bulk Shear
values and strong low level directional shear, especially across
Deep East Texas, into N LA and SC AR. Confidence in strong that
storms will take on a linear depiction on Monday thus, resulting
in a straight-line damaging wind threat but shear vectors will
support weak, short-lived tornadoes embedded in the line. The
possibility of discrete supercell thunderstorms in advance of the
line is more uncertain but this would be more likely across our
far eastern parishes of NC LA during the afternoon and thus, a
more concerning tornado threat would exist. Because of this
uncertainty, SPC continues to advertise a SLGT risk for Monday
across our eastern half but even a slight tick upwards of
instability and/or the hint of discrete supercell thunderstorms
in future model runs would support and ENH upgrade and that
determination will be made later this afternoon.

Thanks for the coordination this morning SPC, LZK, JAN and LCH.
Prelims to follow...13.

&&

.LONG TERM...
(Monday Night through Sunday)
Issued at 147 AM CDT Sun Mar 24 2024

The severe weather threat will end quickly Monday Evening to our
east with the passage of the pre-frontal trough as we await the
upstream passage of the sfc cold front. That front should be
through our northwest half by 12z Tue and through the remainder of
our region by aftn on Tue. The Southern Plains/Lower Miss Valley
will still be under the influence of the upstream longwave upper
trough and it`s not until late Wed/Wed Night that this system will
finally eject out across our region. There will be enough upper
forcing with the trough to support at least slight chance pops
across our southwest half Wed Night if we are able to saturate the
low levels of the atmosphere sufficiently to get the precipitation
to the ground which looks unlikely at this time to support
anything greater than slight chance pops for Wed Night attm.

Upper ridging will dominate across the Southern Plains/Lower Miss
Valley for Thu and through at least Sunday for now. The next
upstream trough appears that it will cutoff across the southwest
Great Basin by the weekend which should delay it`s impacts across
our region until beyond this 7-day forecast cycle.

13

&&

.AVIATION...
(12Z TAFS)
Issued at 641 AM CDT Sun Mar 24 2024

For the ArkLaTex terminals, VFR continues everywhere this
aftn/eve, but MVFR cigs will be arriving 06-12Z. SFC winds will
be the big story as the pressure gradient ramps up ahead of
Monday`s SVR threat. SE 5-15KT early today will veer to S/SE and
increasing to 10-20G30KT by 18Z. The evening will keep sustained
15-20KT, but fewer gusts until -TSRA arrive early Monday. The
dvlpg line of TS will edge toward KTYR/KTXK 12-15Z Mon. & then
have heating for some SVR across the remainder of our cwa. /24/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  72  63  72  49 /  10  10 100  10
MLU  69  59  75  51 /   0  10  90  60
DEQ  67  54  65  37 /  10  90  90  10
TXK  68  59  68  43 /  10  50 100  10
ELD  67  57  68  45 /   0  20 100  30
TYR  72  58  71  44 /  10  70  80   0
GGG  72  59  71  44 /  10  40  90   0
LFK  74  62  73  48 /   0  10 100   0

&&

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

$$

SHORT TERM...13
LONG TERM....13
AVIATION...24


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