072
FXUS64 KSHV 181132
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
632 AM CDT Sat May 18 2024

...New AVIATION...

.SHORT TERM...
(Saturday through Sunday)
Issued at 200 AM CDT Sat May 18 2024

Water vapor imagery early this Saturday morning depicts a split-
flow pattern in the mid and upper levels of the atmosphere across
the CONUS, with the northern stream featuring a belt of strong
cyclonic flow from the Pacific Northwest eastward through the
Northern Plains, and an upper level trough extending from the
Southern Plains eastward through the TN Valley in the southern
stream. Near the surface, a weak trough of low pressure is noted
across Northern TX extending eastward across central/southern
Arkansas and into the TN Valley, while a quasi-stationary boundary
remains situated across the Northern Gulf and near the MS/AL/FL
panhandle coastlines.

A tranquil morning will continue across the Four State Region,
aside from areas of fog developing and continuing through about
mid-morning as skies scatter, winds remain light, and grounds
remain moist. Could see some locations where visibility is reduced
to 1/4 mile or less and conditions meet dense fog advisory
criteria, however, at present time do not feel this will be
widespread enough to warrant issuing an advisory, especially given
the uncertainty in how some passing high clouds may affect
radiational cooling. In addition to the fog, a few showers, and
even a thunderstorm, has developed along the aforementioned sfc
trough across AR as of 07z. This activity may continue through
daybreak and possibly further into the morning, but will pose no
severe threat and will not amount to much in the way of
QPF/additional rainfall.

The upper level trough will continue to slowly swing across the
region through the day today, with the best dynamics being slowly
displaced to the east with it through the afternoon and evening.
This will result in an overall dry day. Given the presence of the
trough through much of the day, along with the residual sfc trough
(altho this should weaken thru the day), really cannot completely
rule out a shower or two thru the entirety of the day. Skies will
be generally partly cloudy, with a nice cumulus field developing
this afternoon.

The upper level trough will finally exit the area to the east
tonight and into early Sunday, giving way to an upper level ridge
of high pressure. This will result in increasing subsidence aloft,
with skies clearing after sunset and through the night. These
conditions, combined with calm winds will give way to another
night of fog development, continuing into Sunday morning.

Sunday will be dry as high pressure dominates both at the surface
and aloft. Ridging aloft will allow temperatures to climb into the
low 90s Sunday afternoon (upper 80s to near 90 across SE OK and SW
AR). These hot and dry conditions will then carry us into the long
term forecast period.

Kovacik

&&

.LONG TERM...
(Sunday Night through Saturday)
Issued at 200 AM CDT Sat May 18 2024

The upper level pattern to begin the long term will feature high
pressure both aloft and at the surface. This will result in
continued dry conditions Sunday night into Monday, with overnight
lows ranging from the low 70s across much of SE TX and NW LA and
upper 60s across SE OK and SW AR under clear skies.

The ridge will remain firmly in place on Monday, resulting in a
rather hot May day with temperatures climbing into the low to mid
90s. The pressure gradient will begin to increase during the late
afternoon and evening hours as sfc cyclogenesis gets going across
the TX/OK panhandles. This will allow for increasing southerly
winds near 10 mph across at least western portions of the area,
which may provide at least some relief from the heat.

By Tuesday, a shortwave trough, associated with a broad scale
trough across much of the Western US, will eject into the Central
Plains, which will nudge the ridge over the Four State Region
slightly eastward. Sfc ridge influence over the area will also
move well east as lee cyclone moves NE into the Central
Plains/Midwest. This will allow for some low level cloud cover to
advect northward across at least SE TX and possibly W LA during
the morning hours. Will still retain enough upper level ridge
influence for high temps to remain in the low to mid 90s for most
locations. A few showers may begin to encroach upon northern zones
late in the day, associated with a trailing cool frontal boundary
from the aforementioned sfc cyclone. Winds Tuesday will be breezy
10-15 mph.

The upper level ridge will then noticeably dampen on Wednesday as
the large scale western US trough expands eastward and low
pressure deepens over the Upper MS Valley. The cool frontal
boundary from Tuesday is likely to become stationary on Wednesday
as the best dynamics/parent low remain displaced far to the north,
resulting in convection developing along the boundary and not
making much southward/eastward progress. While this will increase
rain and thunderstorm chances across the area, rainfall amounts
appear generally light and this boundary will provide no relief in
terms of scouring out the hot and increasingly muggy airmass.

This boundary is then currently progged to move slowly northward
as a warm front on Thursday as a shortwave moves across central
and east TX, keeping rain and storm chances in the forecast until
the shortwave can finally carry the boundary east with into
Friday. At this point in time cannot completely rule of the
potential for a few severe storms in the Wednesday/Thursday
timeframe, but do not think it will be widespread.

Currently then seeing little in the way of an airmass change, so
Friday may bring the chance for more typical isolated, single-cell
convection driven largely by diurnal processes. General ensemble
consensus via WPC Cluster Analysis suggests upper level ridge to
maintain some influence into next weekend.

Currently do not anticipate the need for any heat-related
headlines through the long term nor is there any strong signal for
widespread severe weather or heavy rainfall/flooding.

Kovacik

&&

.AVIATION...
(12Z TAFS)
Issued at 627 AM CDT Sat May 18 2024

Upper trough continues to swing east across the airspace this
morning as the associated upper low sits NE of the airspace.
Patches of FG/BR are present near and at the area terminals, and
should begin to burn off following sunrise. As a result, TEMPO
groups have been added to accommodate any longer lasting BR this
morning. CU field should develop this afternoon, with greater
coverage across the central and eastern terminals where BKN
coverage will be likely. The CU field should decay by the evening
and into the overnight where calm winds and SKC/FEW will prevail,
thus supporting additional FG/BR development by early Sunday AM.

RK

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  90  69  92  72 /   0   0   0   0
MLU  87  68  90  69 /  10   0   0   0
DEQ  87  63  89  68 /   0   0   0   0
TXK  88  67  92  71 /   0   0   0   0
ELD  87  65  91  68 /  10   0   0   0
TYR  88  69  91  71 /   0   0   0   0
GGG  88  68  91  71 /   0   0   0   0
LFK  89  68  92  70 /   0   0   0   0

&&

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

$$

SHORT TERM...23
LONG TERM....23
AVIATION...53