000
FXUS64 KSHV 222339
AFDSHV
Area Forecast Discussion
National Weather Service Shreveport LA
539 PM CST Fri Jan 22 2021
.AVIATION...
For the 23/00z TAFs, a few scattered showers will move eastward
across Northeast Texas, Southern Arkansas, and Northern Louisiana
early in the period. However, this activity is not expected to
affect the TAF sites. Flight conditions should generally fall into
the IFR/LIFR categories areawide as low ceilings and patchy fog,
including patchy dense fog, develops before 23/06z. Visibilities
should quickly improve after sunrise. Ceilings will be much slower
to lift, but MVFR flight conditions are expected at all TAF sites
after 23/18z.
CN
&&
.PREV DISCUSSION... /issued 308 PM CST Fri Jan 22 2021/
SHORT TERM.../Tonight through Saturday night/
The leading edge of the drier sfc air continues to seep S across
Lower E TX and NCntrl LA this afternoon, just S of the I-20
corridor where dewpoints have fallen off into the upper 40s to
near 50 degrees. While the afternoon water vapor imagery indicates
a considerable wedge that has advected E across much of the region
this afternoon, a few isolated areas of light rain have
redeveloped across portions of E TX/N LA where weak elevated
isentropic lift remains atop the shallow cool air mass in place.
Even as this shallow air mass continues to settle S into SE TX ad
Scntrl LA tonight, the H925 flow will become E this evening and
then SE late tonight, thus ending the erosion of the back edge of
the stratocu across SW AR this evening, with this cloud cover
quickly returning back N over these area by or shortly after
daybreak Saturday. The global and hi-res short term progs are in
agreement with weak overrunning commencing over the area atop the
shallow cool air dome this evening, with even very light amounts
of QPF through the overnight hours over E TX/N LA along and S of
I-20. Given the very light QPF forecast amongst the majority of
the progs, have inserted slight chance pops tonight for these
areas, with this overrunning progged to gradually spread back to
the NE during the day Saturday. Thus, have added slight chance
pops for these areas given the overall agreement amongst the
various models with the very light QPF in the weak overrunning
regime.
Weak cold advection ongoing attm through tonight will result in
cooler min temps tonight, but the considerable stratus/stratocu
field should keep the extent of cold advection at bay, and thus
have continued the trend with temps a bit above the colder NBM,
with the coldest temps expected to be over SE OK/Nrn sections of
SW AR where the stratocu has temporarily cleared/scattered over
these areas this afternoon. Also continued the trend of max temps
Saturday cooler than the NBM given the extensive low stratocu
field and damp conditions.
The upper flow will begin to transition back to SW by Saturday
night well ahead of the upper troughing now digging through Cntrl
CA, which will wobble through the state Saturday before entering
the Desert SW Sunday. Weak PVA remains progged to increase
Saturday night within the SW flow, with sct SHRA increasing during
the evening across E TX, before spreading across the remainder of
the region overnight. This will be near and N of a warm front,
which will begin its Nwd advance across E TX/N LA Saturday night,
and into the Red River Valley and Srn AR Sunday. Variability still
exists amongst the progs with the placement/extent of QPF, and
thus have maintained high chance pops for much of E TX/NW LA/SW
AR/extreme SE OK, tapering pops to mid and low chance farther E
across Ncntrl LA/SCntrl AR. Min temps Saturday night will likely
be achieved during the evening, before temps slowly rise overnight
as the warm front lifts N into E TX/N LA.
15
LONG TERM.../Sunday through Friday/
By Sunday morning, a warm front along the coast and extending back
across east central Texas will quickly begin lifting back northeast
across our region. The warm front will bring increasing moisture
from the Gulf along with increasing showers, which will gradually
expand in coverage and intensity by Sunday afternoon with isolated
thunderstorms also developing. The warm front should clear the area
late in the day as warm air advection will push high temperatures
into the 60s to lower 70s on Sunday despite the thick cloud cover
and increasing convection throughout the day.
By Sunday night into Monday, expect convection to become even more
concentrated with increasing upper level support from a significant
shortwave trough pivoting east from the Desert Southwest into the
Southern Plains. Due to the unseasonably warm and moist atmosphere
in place ahead of the trough and accompanying cold front, look for
thunderstorms to become more numerous during this timeframe as the
lift and forcing ahead of the sfc and upper level features is near
peak intensity. The limiting factor still appears to be instability
in the lower levels and near the sfc, but mid-level lapse rates look
to be quite impressive at over 8C/km coupled with increasing bulk
shear. As such, the potential for at least some isolated strong to
severe thunderstorms cannot be ruled out from Sunday night through
Monday morning. This threat, if it materializes at all, does appear
to be greatest along and north of the I-30 corridor with large hail
and damaging winds as the primary threats.
The upper level shortwave and cold front will quickly shift east of
the area by Monday afternoon, and this will allow for any lingering
convection to quickly come to an end. Dry conditions will resume for
Tuesday before another upper level trough ejects out of the Rockies
on Tuesday night into Wednesday. Moisture availability ahead of this
trough still looks to be quite limited with rain chances generally a
bit higher across our eastern half and lower farther to the west. An
upper level ridge will quickly build across the region on Thursday
and allow for some welcome sunshine through the end of next week.
/19/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 46 54 50 68 / 20 20 50 80
MLU 44 52 49 68 / 20 20 30 70
DEQ 36 46 41 62 / 10 20 50 70
TXK 40 48 45 64 / 10 20 50 80
ELD 38 49 43 65 / 10 20 40 90
TYR 47 57 53 69 / 20 20 50 90
GGG 46 55 51 69 / 20 20 50 80
LFK 52 63 57 72 / 20 20 50 70
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
09/20
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