000
FXUS64 KSHV 291751
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
1151 AM CST Sun Jan 29 2023

...New AVIATION...

.UPDATE...
Issued at 953 AM CST Sun Jan 29 2023

Warm sector elevated convection this morning continues across the
I-20 corridor with more expected through the afternoon as a cold
front associated with a sfc low located across E/OK advances east,
now entering our NW zones. As the boundary moves east, this will
only help to enhance showers and storms this afternoon adding to
the rain totals already present from this mornings thunderstorms.
With the advancing front and timing of its arrival, temperatures
across the NW zones will fall through the afternoon and evening.
Morning sounding out of Norman, OK where the boundary had passed
by the 12z launch time indicated a shallow airmass at roughly
2100ft. Given the higher terrain upstream of the airmass, it may
be difficult for the airmass to deepen further before the damming
effect occurs around the Ouachita Mountains later on in the
forecast. For now, the forecast continues to stay on pace this
morning. No changes have been made to the high temp forecast as
highs will settle in the mid to upper 60s near 70 behind the
decaying warm front, with an early finish to daytime heating
across NW zones as the front rolls in. Any subtle breaks in the
clouds ahead of the front may allow for a brief period of further
warming before coverage quickly returns.

/53/

&&

.SHORT TERM...
(Sunday through Monday)
Issued at 240 AM CST Sun Jan 29 2023

Latest sfc analysis shows the retreating warm front has moved
just about completely north of our CWA attm in advance of the
leading edge of arctic air spilling south and east across NE OK
into the Upper Red River Valley of N TX and SW OK. Looking aloft,
southwest flow continues to dominate our region early this morning
and weak upper forcing combined with isentropic processes has
resulted in a continuation of scattered to numerous showers and
isolated thunderstorms across what has become a pretty widespread
warm sector in the wake of the returning warm front at the
surface. As we move through the day, look for the greatest storm
coverage to be oriented across the southeast half of the warm
sector, or mainly near and to the south and east of the I-20
Corridor. The leading edge of the very cold airmass to our
northwest will slowly bleed into our region by mid morning, likely
not making it into NW LA until late this afternoon. Therefore,
expect high temperatures today to be reached this morning across
our northwest half with falling temperatures along with a wind
shift throughout the day behind the cold front.

Precipitation should end from northwest to southeast across our
region this evening, just about the time we see subfreezing
temperatures move into our far northwest zones after midnight
tonight. Trended overnight low temperatures below NBM values,
closer to a blend of the warmer MAV MOS and much colder MET MOS
temperatures.

For Monday, again, trended temperatures closer to the colder
MET MOS temperatures as NBM/MAV MOS values just appear too warm
with the very shallow, yet very cold airmass that will settle into
our region. We should begin the day on the dry side but look for
increasing rain chances overspreading out region from west to east
during the late morning and afternoon with continued disturbances
moving our way providing the necessary forcing in southwest flow
aloft. Kept returning precipitation across our region during the
day Monday of the liquid variety but that my change as we enter
the overnight period Monday Night across our far northwestern
zones but more on that in the long term discussion below.

13

&&

.LONG TERM...
(Monday through next Friday)
Issued at 215 PM CST Sat Jan 28 2023

During the upcoming work week, a closed upper trough will continue
to slowly dig south across the California coast into the Baja and
Northern Regions of Mexico, while a large ridge will be firmly in
place across the Central Gulf of Mexico. This will keep a persistent
SW Flow aloft pattern in place over the region during the upcoming
work week, with an overrunning weather set-up likely developing. This
wet period could lead to possible flooding concerns through next
weekend.

By Monday evening into Tuesday morning, the combination of
isentropic upglide and weak disturbances moving along the flow, will
ramp up precipitation across the region. However, this overrunning
precip will be moving over a shallow cold airmass that will be in
place in wake of the previous day frontal passage. This is where the
forecast gets tricky. Long-term progs are hinting at enough cold air
to support freezing rain in portions of the region. But, the extent
of the freezing rain is the biggest question mark.  Most of the
progs keep the freezing precip in extreme northern McCurtain County
Oklahoma. However, the NAM, which historically performs well with
shallow airmasses, wants to bring the chance for freezing rain as
far south as the I-30 corridor of East Texas and SW Arkansas. At
this time, decided to stay with NBM and keep frozen precip confined
to McCurtain County , as this event is still a few days out and the
NAM is the outlier. Regardless, it appears ice accumulations will be
very small, as temps will be hovering right at the freezing mark
during this event.

Overrunning is expected to continue across the region through the
remainder of the upcoming work week, as more disturbances will move
along the flow ahead of the Baja trough that will continue to slowly
progress eastward towards the region. Models suggest temps will
modify as we move through the work week, but with the rain and cloud
cover, afternoon temps will remain well below normal. There is an
additional chance for freezing rain again late Tuesday night into
Wednesday morning across northern McCurtain County, but the ice
accumulations also look to be minimal as well. The main concern
continues to be the potential for flash flooding, along with
flooding to area waterways, as storm total QPF amounts are
indicating widespread 3-5+ inches of rainfall.

By Thursday, the Baja trough will start to eject out of Northern
Mexico into Texas, before shifting into the Lower Mississippi Valley
and the SE CONUS by Friday. Precipitation will finally come to an
end, as the pattern will shift into a drier northwest Flow aloft.
These dry conditions should remain over the area through next
weekend, with near normal temperatures. /20/

&&

.AVIATION...
(18Z TAFS)
Issued at 1137 AM CST Sun Jan 29 2023

Mix of flight categories once again present across all terminals
as low CIGs, TSRA, SHRA and BR are present. Expect this trend to
continue through the early and middle stages of the 29/18z TAF
period as a cold front cuts through the airspace later this
evening and overnight. With this in mind, while the RA may
decrease as the boundary moves through, guidance continues to
highlight lowering ceilings with BR through the late stages of the
TAF period with IFR conditions possible, potentially even a few
LIFR conditions at select terminals, especially eastern terminals,
as the boundary approaches by the morning. NW winds post boundary
are already ongoing across NW and western terminals. This theme
will carry from west to east as the period progresses, generally
between 5-10kt with an occasional gust or two.

/53/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  46  52  42  43 /  50  30  60  60
MLU  48  55  42  43 /  70  20  40  40
DEQ  34  44  36  41 /  20  20  70  80
TXK  42  47  38  41 /  30  20  70  80
ELD  42  48  36  39 /  50  20  60  60
TYR  35  42  39  41 /  10  40  70  80
GGG  39  47  41  43 /  30  40  70  70
LFK  45  52  46  50 /  30  40  50  50

&&

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

$$

SHORT TERM...13
LONG TERM....20
AVIATION...53

NWS SHV Office Area Forecast Discussion