Severe Thunderstorm Warning 396, NWS Shreveport, LA

Area Forecast Discussion
National Weather Service Shreveport LA
626 AM CDT Tue Aug 19 2025

...New AVIATION...

.KEY MESSAGES...
Issued at 121 AM CDT Tue Aug 19 2025

 - Oppressive heat wave will continue today, with more widespread
   triple digit temperatures expected. Combined with the humidity,
   more widespread heat indices in excess of 110 degrees are
   expected across extreme Southern Arkansas and much of North
   Louisiana, with an Extreme Heat Warning issued for these areas.

 - Afternoon convection should be more isolated this afternoon,
   before diminishing during the evening.

 - Slightly cooler but very hot temperatures will return Wednesday,
   with scattered showers and thunderstorms increasing through
   the day, eventually yielding needed rainfall and cooler
   conditions, which will continue into Thursday and Friday.

&&

.DISCUSSION...
Issued at 121 AM CDT Tue Aug 19 2025

The early morning upper air analysis again indicates a large area
of expansive ridging extending from the Srn Rockies E through the
Cntrl/Srn Plains into the Mid MS/TN Vallies to the Mid-Atlantic
states, and remains progged to hold firm for one more day before
finally beginning to retreat to the W by Wednesday as weak
troughing begins to dig SSE through the MS Valley. Satellite
imagery still reveals mainly elevated convective debris lingering
over much of E TX/Wrn LA/portions of Srn AR early this morning,
associated with slowing diminishing convection that continues to
propagate SW through SE TX. These cigs should eventually thin with
time through daybreak, but should help hold temps up so that we
get a head start on another day of brutal heating.

The overall trend in temps in the last few days has been a
gradual uptick as the topsoils continue to dry out, and with the
overall synoptic pattern unchanged, the potential for even hotter
than Hades conditions exist today. Slightly drier air did
backdoor SW into the region Monday afternoon, but not before more
widespread 110+ heat indices peaked by early afternoon before
settling back a tad due to the mixing of the drier air as well as
the increase in isolated to scattered convection. However, a key
difference today than Monday is the lack of any weakness aloft
depicted in the various short term progs this morning, despite the
1.7-2.0 inch PW's that are expected to remain over the area.
Thus, believe that more in the way of isolated (than scattered) convection
is expected this afternoon in this air mass, but should do little
to interfere with strong diurnal heating that will commence by
mid- morning. For these reasons and after coordination with
adjacent WFO's, have upgraded the existing Heat Advisory to an
Extreme Heat Warning today for extreme Srn AR, much of North LA,
and portions of adjacent E TX through 01Z Wednesday, with max heat
indices possibly reaching as high as 115 degrees.

As stated above, the retreating ridge will allow for weak
troughing to settle S through the Ozarks Wednesday, with PVA
advancing S ahead of it atop the hot, moist, and unstable air mass
contributing to an increase in scattered convection especially
during the afternoon across the region. It's to difficult to gauge
the extent of convection coverage Wednesday afternoon given the
very weak shear and weak forcing aloft, with the convection being
more mesoscale driven. The various MOS output are also not very
bullish at all with pops Wednesday afternoon, which leads credence
to increased uncertainty as to the extent of convection
development. For these reasons, have tapered back likely NBM pops
to high chance over much of the region Wednesday afternoon, and
will adjust as needed closer to the forecast period should
mesoscale features be more pronounced. Heat headlines will likely
be needed over much of the area Wednesday prior to the convection
initiation, although increased cloud cover/rain cooled air and the
potential for additional redevelopment Wednesday night/Thursday
will result in cooler temps and a break for the more oppressive
heat for the latter half of the work week.

The various ensembles are a bit faster in translating the weak
trough/shear axis S into S TX/Cntrl and S LA by Friday, which
would focus mainly scattered diurnal convection along/S of I-20,
before a deeper wedge of drying commences in its wake ahead of the
Four Corners ridge as it begins to expand back ESE into the Lower
MS Valley this weekend. Thus, a return to the oppressive heat is
expected by this time, but may be tapered somewhat as the ridge
begins to flatten over the Srn Plains at the end of the forecast
period early next week in response to more pronounced troughing
progged to develop from the Nrn Plains/Midwest into the OH Valley.

Thank you WFO's LZK/JAN for coordination this morning.

15

&&

.AVIATION...
(12Z TAFS)
Issued at 623 AM CDT Tue Aug 19 2025

Mainly VFR conditions to prevail across area terminals through
the forecast period ending 20/12Z. A weak pressure gradient will
allow for northeast winds near 5 knots this afternoon. Winds to
again become light and variable after 20/00Z. Otherwise, VCTS
conditions may be possible across most terminal sites except for
LFK during the late afternoon into the early evening. /05/

&&

.SPOTTER INFORMATION STATEMENT...
Issued at 1210 AM CDT Tue Aug 19 2025

Spotter activation should not be needed through tonight. /15/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV 104  78  99  76 /  20  10  50  40
MLU 102  75  98  73 /  20  10  50  40
DEQ 103  72  96  71 /  20  30  40  20
TXK 105  77  99  74 /  20  20  50  30
ELD 102  73  97  72 /  20  20  50  30
TYR 100  77  97  74 /  20  10  50  40
GGG 102  75  98  74 /  20  10  50  40
LFK  98  75  98  73 /  20  10  50  40

&&

.SHV WATCHES/WARNINGS/ADVISORIES...
AR...Heat Advisory until 8 PM CDT this evening for ARZ050-051-059>061.

LA...Heat Advisory until 8 PM CDT this evening for LAZ017>020-022.

OK...Heat Advisory until 8 PM CDT this evening for OKZ077.

TX...Heat Advisory until 8 PM CDT this evening for TXZ096-108>111-124-
     125-136-137-149>153-165>167.

&&

DISCUSSION...15
AVIATION...05

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