300
FXUS64 KSHV 070808
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
308 AM CDT Tue May 7 2024

...New SHORT TERM, LONG TERM...

.SHORT TERM...
(Tuesday through Wednesday)
Issued at 249 AM CDT Tue May 7 2024

Early morning NT Microphysics imagery shows low clouds streaming
north across the FA, as upper-level sheared cirrus from deep
convection across OK/AR drifts west to east, just north of the
I-30 corridor. For the most part, Tuesday will remain dry and
quiet, with the main story through the afternoon being the warmer
temperatures as highs climb into the upper 80`s to near 90 deg F.

Given the extent of the diurnally driven sfc heating this afternoon,
hi-res guidance advertises an aggressive display of surface-based
instability parameters across the Four State Region with SBCAPE
values as high as 3000-3500 J/kg or greater, with 0-6 km bulk
shear values between 40-50 kts, and 700-500 lapse rates between
7-8 C/km. The catch here is that while this may be available,
guidance looks to leave it mostly untapped as forcing remains well
displaced from the local coverage zone, primarily located in a
region of better synoptic forcing and ascent well to the north and
east of the local area.

Morning guidance continues to suggest that a residual sfc
boundary may exist close to the I-30 corridor this afternoon from
overnight convection across Oklahoma. This boundary should wash
out and lose it`s potency due to afternoon mixing. It is worth
mentioning that some CAMs do suggest a secondary instability axis
to drift north into the better sfc parameters, supporting some
limited convective initiation by the evening, but by this point it
may be too late for any deeply rooted convection to evolve. Main
concerns if any thunderstorms are to develop along the
instability axis would be the threat for gusty winds and hail.
This would be located mainly in the Marginal risk zone (level 1
of 5), highlighted in the Storm Prediction Center Day 1 outlook.

Wednesday Severe Threat:

By Wednesday morning, better forcing starts to dig into the Southern
Plains, with a sfc cold front advancing southward, progged to enter
into the Four State Region by mid to late Wednesday afternoon.
Another warm afternoon across the FA will promote further sfc
instability as high temperatures easily climb to 90 deg F and
possibly a degree or two higher. As the boundary clashes with the
local airmass, deeply rooted convective initiation will look to
develop across a region of high SBCAPE profiles approaching, and
possibly even exceeding, 3500 J/kg, 0-6 km bulk shear between
40-50 kts, and steep lapse rates nearing 8.0 C/km.

Though some low level directional shear will be present, supporting
the chance for a tornado or two, the main concern from the
advertised CAMs and HREF solution will be the threat for large hail
within the Enhanced risk (level 3 of 5). Based on latest guidance,
convection should diminish ahead of sunrise Thursday.

RK

&&

.LONG TERM...
(Wednesday Night through Tuesday)
Issued at 249 AM CDT Tue May 7 2024

By Thursday morning, the forward speed of the advancing sfc boundary
will dictate the coverage of the day 3 severe threat locally.
General thinking for now is that the boundary will be located
somewhere between I-30 and I-20, and is progged to slide south
through the afternoon. Afternoon maxT`s south of the boundary will
climb into the upper 80`s and low 90`s, with instability
parameters strongest in this region. Frontal based forcing will
support convective initiation along and ahead of the boundary by
the afternoon, and continue into the evening in the form of a
possible MCS. Primary concerns with the developing convection is
the threat for damaging wind, and large hail. The chance for an
embedded tornado should not ruled out.

The front will sag south of the FA by Friday AM, with high pressure
influencing the region for much of Friday and into weekend. Guidance
overnight now keeps much of the area rain free till about early to
mid next week. Post frontal passage airmass will help return temps
to near normal through the remainder of the forecast period.

RK

&&

.AVIATION...
(06Z TAFS)
Issued at 1207 AM CDT Tue May 7 2024

MVFR ceilings rapidly returning northward from SE TX and SW LA
into our airspace at this late hour this evening and thus, expect
widespread MVFR ceilings to dominate much of our region through
the predawn hours. Cannot rule out a narrow window of IFR ceilings
at the LFK terminal a couple hours either side of sunrise but
given the low level pressure gradient in place, feel like MVFR
ceilings are the better bet vs IFR ceilings across our airspace
through mid to late morning when ceilings return to low VFR
variety. Latest HRRR wants to develop a narrow line of
showers/Isolated TSRA from near LFK to SHV to ELD terminals and
keeps this activity in the same general locations through the
middle afternoon. Cannot find any support for this activity in
other model output so will leave it out of this 06z TAF package
and will reassess with the 12z package. Look for SSE to SSW winds
today to be near 8-12kts sustained with gusts upwards of 20kts,
especially across our NE TX terminal locations.

13

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  89  74  90  72 /  10  10  20  40
MLU  88  73  91  71 /  10   0  10  40
DEQ  86  66  85  63 /  20  20  30  50
TXK  89  72  90  68 /  10  20  30  60
ELD  88  70  90  67 /  20  20  20  60
TYR  88  71  89  71 /  10  10  30  30
GGG  88  72  90  70 /  10  10  30  30
LFK  89  72  91  73 /  10   0  10  10

&&

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

$$

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