698
FXUS64 KSHV 191143
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
643 AM CDT Sun May 19 2024

...New AVIATION...

.SHORT TERM...
(Sunday through Monday)
Issued at 229 AM CDT Sun May 19 2024

A split-flow pattern continues in the mid and upper levels of the
atmosphere early this Sunday morning, with a belt of rather
strong cyclonic flow encompassing the Pacific Northwest, the
Northern Rockies, and Northern Plains in the northern stream,
while a closed, almost cut off low meanders well off the southern
California coast, with weak troughing across the desert SW and an
amplifying ridge of high pressure over the Southern Great Plains
and Lower MS Valley in the southern stream. Near the surface, a
cyclone is centered near the Manitoba/Ontario border, with a cold
front draped S/SW across the Great Lakes and into the Central
Plains. Another area of low pressure is noted across Georgia, with
high pressure over the Lower MS Valley and ArkLaTex and across
the Midwest and Central to Northern Great Plains.

Provided the pattern described above, it`s another quiet morning
across the Four State Region. Skies are clear and winds are calm,
which is allowing for optimal radiational cooling above a moist
surface. Already seeing some patchy fog developing as of 07z and
expect areas of fog to continue through and shortly after
daybreak. Patchy dense fog will be possible where visibility could
be 1/4 mile or less, but will not be widespread enough to warrant
a headline. As fog then dissipates shortly after sunrise, sunny
skies will prevail and temperatures will warm quickly given
subsidence aloft from upper level ridging. A nice cumulus field
will develop again this afternoon, resulting in partly to mostly
sunny skies with high temps creeping into the low 90s (near 90 SE
OK and SW AR).

Tonight, a shortwave trough traversing the Ok panhandle into the
Central Plains is likely to spark convection across OK, with this
activity eventually pushing into Arkansas. This will pose no
threat to the local area, but will likely bring some high cloud
cover to northern zones tonight into early Monday. High clouds
expected to be thin enough to not really affect radiational
cooling, but with some drying of soils through Sunday fog
development and coverage is expected to be much more
isolated/patchy Monday morning vs Sunday morning.

The upper level ridge will hold its place across the area on
Monday, resulting in another hot and dry day with afternoon
temperatures reaching the low to mid 90s. Another afternoon
cumulus field will be present, with southerly winds beginning to
increase across the western half of the CWA in response to surface
cyclogenesis beginning across the OK panhandle.

While the short term period will be hot and dry, dewpoints in the
mid to upper 60s will keep heat indices below 100 degrees. No heat
related headlines will be needed.

Kovacik

&&

.LONG TERM...
(Monday Night through Sunday)
Issued at 229 AM CDT Sun May 19 2024

The large scale pattern to begin the long term period will
feature a fairly high amplitude pattern across the CONUS with a
large scale trough over the Western US and large scale
(relatively) ridging over the Eastern US. An impulse will eject
out of the large scale Western US trough into the Central Plains
Monday night, enhancing lee cyclogenesis across the OK panhandle,
with this sfc cyclone then moving into Kansas Tuesday morning.
This will begin to push sfc high pressure across the ArkLaTex
eastward, with an increasing pressure gradient and enhanced
southerly flow from the GOM northward across E TX. Low cloud cover
is expected over a good portion of western zones Tuesday morning.
Upper level ridge influence then looks to remain strong enough to
make for another hot and partly to mostly sunny day with high
temps again in the low to mid 90. Dewpoints will begin to creep
towards 70 degrees, so it will begin to feel a bit muggier. The
ridge axis will be slowly shifting east of the area late in the
day as an upper level low deepens and closes over the Upper MS
Valley and the Western US trough progresses eastward into the
Plains.

As both the upper level and sfc lows over the Upper MS Valley
deepen substantially Tuesday night into Wednesday, convection will
develop along the associated frontal boundaries, the cold frontal
portion of which will extend S/SW into AR and N TX. Convection
along the front in our neck of the woods is likely to be enhanced
by additional short wave perturbations, so expect rain and storm
chances to return to far northern zones late Tuesday into
Wednesday. SPC has clipped far northern zones in a marginal risk
for severe weather.

On Wednesday, the upper level ridge will dampen, leaving its
influence south and east of the area, with the upper level flow
turning more quasi-zonal to SW. The frontal boundary will slowly
sink towards the LA/AR border and despite the best dynamics from
the parent system being displaced well to the north across the
Great Lakes, shortwaves within the weakly-oriented SW flow will
fire convection across the boundary Wednesday afternoon and
evening. While not outlooked by SPC on Wednesday, given dewpoints
around 70 or into the low 70s and the boundary in the CWA, a few
strong to severe storms certainly appear possible, esp given model
projected mean layer instability in the 1000-2000J/kg range.

Wednesday night into Thursday, this boundary is likely to either
remain stationary or gently shift northward. With an unstable
environment encompassing just about the entire CWA on Thursday,
the threat for severe weather will exist, especially as another
shortwave looks to pass overtop the boundary carry the boundary
back into/across the area. SPC currently has the area outlooked
and will watch this closely over the next few days.

The boundary and the shortwave will then pass to the east on
Friday, with little to essentially no change in airmass and
additional shortwaves passing across the area. A few showers and
thunderstorms appear possible Friday afternoon and evening, more
diurnally driven than previous days. The same story appears likely
for Saturday before general ensemble consensus leans towards the
rebuilding of the upper level ridge. High temps look hot to end
the forecast period, in the mid 90s with dewpoints near 70 or in
the low 70s, resulting in heat indices near or just above 100
degrees.

Kovacik

&&

.AVIATION...
(12Z TAFS)
Issued at 640 AM CDT Sun May 19 2024

A few widely scattered instances of patchy fog may result in brief
MVFR/IFR visibilities during the first two to three hours of the
TAF period. However, VFR flight conditions should prevail areawide
by mid-morning and should persist through the rest of the this TAF
cycle. The exceptions might be for some patchy fog to once again
briefly affect KELD and KMLU between 20/06z-20/12z.

CN

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  92  71  93  72 /   0   0   0   0
MLU  90  67  92  69 /   0   0   0   0
DEQ  89  66  89  67 /   0   0   0   0
TXK  92  69  93  71 /   0   0   0   0
ELD  91  66  92  68 /   0   0   0   0
TYR  91  70  90  72 /   0   0   0   0
GGG  91  69  91  70 /   0   0   0   0
LFK  91  69  91  70 /   0   0   0   0

&&

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

$$

SHORT TERM...23
LONG TERM....23
AVIATION...09