086
FXUS64 KSHV 070328
AFDSHV
Area Forecast Discussion
National Weather Service Shreveport LA
1028 PM CDT Mon May 6 2024
...New UPDATE...
.UPDATE...
Issued at 1026 PM CDT Mon May 6 2024
No update is needed to the afternoon forecast package at this
time. Small update to introduce the new tornado watch into the
zones.
/44/
&&
.SHORT TERM...
(This evening through Tuesday Night)
Issued at 311 PM CDT Mon May 6 2024
Widely scattered convection is finally beginning to develop across
the region, in advance of a weak shortwave trough noted over E TX.
Some erosion/lifting of the morning stratus field has yielded
strong insolation and an unstable air mass areawide, characteristic
of SBCapes near or in excess of 3000 J/kg. Thus, additional
scattered convection development is expected to continue through
early evening, as this parent shortwave shifts NE through Srn AR/N
LA before exiting. Some additional convection may linger a little
longer though across SE OK/adjacent sections of SW AR, as a SWrly
LLJ intensifies to 40-50kts along a low level theta-e axis ahead
of the strongly negative tilt upper trough as it pivots through
Cntrl and Ern OK into the Ozarks. Very strong forcing/instability
along the Ewd advancing dryline will eventually lead to the
development of multiple supercells over Wrn and Cntrl OK later this
afternoon into the evening, which may consolidate into a linear
line as it quickly advances ENE through Ern OK into the Ozarks
overnight. Some of the latest CAMs continue to suggest that this
line may near Nrn McCurtain County OK and the adjacent Nrn SW AR
counties between 08-10Z, but will likely quickly weaken as the
best forcing aloft shunts NE away from the area with the ejecting
trough. Did place low to mid chance pops over this area for the
expected decaying convection, which may be sustained by the SWrly
LLJ and any residual instability remaining.
Hot, humid, and quiet conditions should return Tuesday, with
mostly dry conditions expected as what`s left of any mesoscale
bndrys from the decaying morning convection eventually washing
out with the onset of mixing. The sfc dry line is progged to mix E
into SE OK, NW AR into or just E of the Ozarks during the
afternoon, with some slightly drier air eventually mixing into SE
OK/adjacent SW AR. What`s left of this bndry should quickly begin
to lift back N/wash out by Tuesday night, although it could still
focus isolated convection overnight over SE OK/Nrn sections of SW
AR especially with the onset of the SWrly LLJ. Deep lyr moisture
is not expected to remain shallow, with no discernible
perturbations progged in the SW flow before eventually reloading S
of the closed low that is progged to spin over the Midwest.
15
&&
.LONG TERM...
(Wednesday through next Sunday)
Issued at 311 PM CDT Mon May 6 2024
The aforementioned closed low is progged to send a weak cold front
SE into the Srn Plains Wednesday, as it nears extreme NW AR into
SE OK/N TX by late afternoon. The GFS/ECMWF suggest that a
developing perturbation in the SW flow will help yield scattered
convection development by mid and late afternoon from NE TX into
SE OK/SW AR near and ahead of the front, coincident of very strong
instability that will develop as sfc temps near/exceed 90 degrees.
H700-500 lapse rates are progged to be steep, ranging from 7.5-8.0
C/km, thus promoting very strong updraft growth within a zone of
strong deep lyr shear. Thus, pending the strength of the
perturbation in the SW flow, severe thunderstorms appear likely
over these areas, where an Enhanced Risk has been outlined by SPC
in the Day 3 Outlook. This convection should persist into the
evening before shifting NE, with the attendant cold front
drifting S into E TX/N LA by daybreak Thursday. Depending on
whether the front temporarily stalls along/just S of the I-20
corridor Thursday or not, it appears that scattered convection
will redevelop near the bndry which could again flare up/become
severe, before finally shifting S of the area Thursday night.
Did highlight this area with mid/high chance pops Thursday
afternoon/evening, before cooler and slightly drier air begins to
spill S in wake of the cold fropa. The latest ensemble guidance
suggests that mostly dry conditions will prevail Friday through
most of the upcoming weekend, with near normal temps expected
through the period. Some of the deterministic guidance do suggest
that some weak perturbations may help enhance some convection
development this weekend, although refinements to the forecast are
likely in the coming days.
15
&&
.AVIATION...
(00Z TAFS)
Issued at 808 PM CDT Mon May 6 2024
For 07/00z TAFS....Low cigs and reduced flight categories will
move into the region overnight and hold through mid morning. Can`t
rule out possible showers, and maybe a thunderstorm at KTXK, as
short-term progs are bringing a decaying line of convection into
that area around daybreak. Otherwise, should see VFR conditions
with scattered CU by the end of the period. Also, can`t rule out
an isolated afternoon shower or thunderstorm with daytime
heating. Expect winds to pick up from the south to between 10 to
15 mph, with gusts up to 20 mph. /20/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 74 89 74 91 / 10 0 0 20
MLU 72 88 72 91 / 10 10 0 10
DEQ 69 86 65 86 / 40 20 20 50
TXK 73 88 72 90 / 20 10 10 50
ELD 71 87 70 90 / 10 10 10 20
TYR 73 88 73 90 / 10 0 0 30
GGG 73 88 72 90 / 10 0 0 30
LFK 73 89 72 91 / 0 0 0 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
SHORT TERM...44
LONG TERM....44
AVIATION...20
NWS SHV Office Area Forecast Discussion
