Rocky Branch, Louisiana Weather Forecast Discussion

161
FXUS64 KSHV 230621
AFDSHV
Area Forecast Discussion
National Weather Service Shreveport LA
121 AM CDT Tue Sep 23 2025
...New AVIATION, SPOTTER INFORMATION STATEMENT...
.KEY MESSAGES...
Issued at 1248 AM CDT Tue Sep 23 2025
- Strong to severe thunderstorms possible Tuesday evening through
   most of Wednesday, including a risk for damaging winds, large
   hail and tornadoes Tuesday evening into early Wednesday.
- Rainfall totals of 1 to 3 inches are possible through Thursday
   afternoon, and locally heavy rain rates may pose a risk for
   flash flooding late Tuesday and into early Wednesday.
- Dry weather after Thursday with temperatures expected to be
   near seasonal norms.
&&
.DISCUSSION...
Issued at 1248 AM CDT Tue Sep 23 2025
A positively-tilted upper trough currently over the Central
Rockies will gradually move into Kansas by early Wednesday
morning. In response, a surface low and associated cold front are
expected to strengthen and become better defined during the day
Tuesday. Hot and humid conditions will continue areawide Tuesday.
Afternoon temperatures in the upper 80s to mid 90s and dewpoints
well into the 70s areawide will yield peak heat index values near
or over 100 degrees F in most locations. Several models suggest a
scattered showers and thunderstorms may develop across portions
of Louisiana and East Texas Tuesday afternoon in the warm air
advection regime, especially with the amount instability in place.
The most likely areas should be southeast of a line from Lufkin,
to Shreveport to Monroe.
More robust convection should develop along the advancing cold
front from North Texas, into Oklahoma, and into Western Arkansas.
There is considerable disagreement among the models regarding the
arrival time of the storms into our area. Most of the guidance
brings the convection into areas north of Interstate 30 late in
the evening between 03z-06z (10 PM CDT-1 AM CDT). However, a few
of the higher resolution CAMs, notably the HRRR, are faster and
bring convection into McCurtain County shortly after 00z (7 PM
CDT). The slower arrival time is more consistent with previous
forecast issuances and model runs, however, I did increase pops
north of I-30 between 00z-03z for this forecast package to account
for the CAMs. Instability and deep layer shear should be
sufficient for at least a few severe thunderstorms Tuesday evening
and into early Wednesday morning, especially as the convection
first moves into the area. Damaging winds, large hail, and a brief
tornado or two will be possible. PWAT values of over 2 inches
will be well over the observed 90th percentile in the climatology.
Combined with somewhat slow storm motions, efficient rainfall
producers may yield locally heavy rainfall rates and a localized
flash flood threat in Southeast Oklahoma and adjacent portions of
Southwest Arkansas and extreme Northeast Texas Tuesday evening
through Wednesday morning.
Showers and thunderstorms will continue to spread southeast,
expanding in coverage, during the day Wednesday. While overall
rain duration may last longer south of I-30 on Wednesday, rain
rates are expected to be lower during the day as the convection
shouldn`t be as intense. There is still a Marginal Risk for severe
thunderstorms Wednesday, but this should mainly be Wednesday
afternoon and evening for locations that can remain in the warm
sector ahead of the front and build some instability. The most
favored area will be southeast of line from Lufkin to Monroe. The
precip should finally begin to slowly diminish from northwest to
southeast Wednesday evening The NBM is still holding onto PoPs and
QPF through the day Thursday. However, most of the latest model
guidance show the rain should completely exit the area Thursday
morning. Typically, the NBM is too slow with the ending of the
precip, and it could very well be underestimating the post-frontal
dry air advection in this case.
Beyond Thursday, dry conditions should return as ridging aloft and
at the surface dominate. Temperatures should cool back to near
seasonal norms for Friday through Tuesday.
Nuttall
&&
.AVIATION...
(06Z TAFS)
Issued at 109 AM CDT Tue Sep 23 2025
For the 23/06Z TAF update, MVFR/IFR vis/cigs will arrive from
23/10Z-23/15Z with patchy fog before clearing to VFR through the
rest of the period. Southerly surface winds will continue at 5-10
kts. /16/
&&
.SPOTTER INFORMATION STATEMENT...
Issued at 109 AM CDT Tue Sep 23 2025
Spotter activation is not expected at this time, but could become
necessary by Tuesday afternoon and through the overnight hours.
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV  94  77  87  69 /  20  30  80  40
MLU  94  75  89  69 /  20  10  80  60
DEQ  90  69  80  62 /  20  70  60  10
TXK  94  74  82  65 /  10  60  80  10
ELD  91  70  82  63 /  30  30  90  30
TYR  93  74  81  65 /  10  50  80  20
GGG  93  74  84  65 /  10  40  80  30
LFK  93  74  91  68 /  30  10  80  50
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
DISCUSSION...09
AVIATION...16

NWS SHV Office Area Forecast Discussion