724
FXUS64 KSHV 201425 AAA
AFDSHV

Area Forecast Discussion...UPDATED
National Weather Service Shreveport LA
925 AM CDT Mon May 20 2024

...New UPDATE...

.UPDATE...
Issued at 911 AM CDT Mon May 20 2024

Our 12Z SHV sounding shows a stouter cap than yesterday, which
should help put a lid on any convection today. Earlier we did have
some very isolated and light showers in our northwestern zones and
this was mainly in association with the bottom end of a mesoscale
convective vort in the wake of intense storms north of the Red
River (and well to our NW) late yesterday. These showers have
already pretty rapidly diminished and will this evolution should
yield partly to mostly sunny skies through the day. Temps should
peak a degree or two warmer than yesterday, which will put most
locales in the Four State region peaking in the 90 to 95 degree
range for highs this afternoon. Combined with the low level
humidity, this will likely yield peak heat index values in the 95
to 100 degree range. These values are well above normal for the
date, but still well below official current heat advisory
criteria. That said, try to take it easy and drink plenty of water
if having to work or spend a lot of time outdoors midday through
afternoon today. Otherwise, the previous forecast seems to handle
the situation well through the evening and updates were very
minor. /50/

&&

.SHORT TERM...
(Monday through Tuesday)
Issued at 127 AM CDT Mon May 20 2024

Persistence remains the best forecast tool through the short-term
as this stagnant weather pattern is forecast to continue across
the Southern Plains/Lower Miss Valley.

Upper ridging remains entrenched across the Ohio and Tenn Valleys,
into the Lower Miss Valley with a longwave trough noted across the
Pacific Northwest into the southwest Great Basin. This ridging
will remain in place for the most part tonight into Tuesday as
pieces of energy rotate out of the upstream longwave trough,
remaining well north and west of our region. The lack of any kind
of forcing, either in the low or mid levels due to the
suppressing influence of the upper ridge axis despite increasing
diurnally driven instability, will result in virtually no rain
chances in the short term.

Concerning temperatures, stayed on the higher side of guidance
today given recent trends. Even with the induction of southerly
winds today, should see a little mixing down of afternoon
dewpoints given slightly lower pwats in place. Those pwats will
increase for Tue which will result in less mixing and higher
afternoon dewpoints and thus, higher heat indices. Afternoon heat
indices on Tuesday will likely approach triple digits across some
locations given the higher dewpoints in place with ambient
temperatures mostly in the lower to middle 90s.

13

&&

.LONG TERM...
(Tuesday Night through Monday)
Issued at 127 AM CDT Mon May 20 2024

By Wednesday, the upper ridge axis gets shunted to our east and
this will allow for more in the way of upscale forcing from the
broad trough across the Great Basin. Upper flow will become
southwesterly aloft and ripples in this flow will allow for
the upper forcing necessary for scattered convection across our
northwest half Wed thru Thu. Coverage may be a little greater Wed
Night into Thu depending on the proximity of a cold front that
appears to pull up stationary just northwest of our far northwest
zones by sunrise Thu Morning.

Diurnally driven instability will result in some of the storms
across our north and northwest zones Wed and Thu aftn/evng
becoming strong to severe thus the SPC Slight Risks for severe
thunderstorms both days. There appears to be a stronger forcing
signal perhaps impacting more of our region late Thu/Thu Night
bringing with it the possibility of more widespread convection
with heavier rainfall across at least our northern half before it
exits the region towards sunrise Fri Morning.

Kept low pops in the fcst Fri into Sat across mainly our northern
half even through forcing appears to be weaker than what our
region will have experienced Wed into Thu. With less in the way of
rain chances, that will result in hotter temperatures with
ambient readings well into the 90s both Sat into Sun with triple
digit afternoon heat indices across our southwest half Sat and
nearly areawide by Sun into Mon.

There appears to be a upper level pattern change just beyond this
7-day forecast as the broad upper trough across the Great Basin to
our west gets replaced with strong upper ridging across the
Intermountain West with the broad trough migrating eastward into
Upper Midwest into the Great Lakes. The closer we get to June,
this introduces northwest flow aloft season and the influx of MCSs
across the Southern Plains. We will watch this flow very carefully
through much of next week.

13

&&

.AVIATION...
(12Z TAFS)
Issued at 633 AM CDT Mon May 20 2024

Patchy fog will continue to affect some locations, most notably
KELD, through 20/15z resulting in MVFR/IFR visibilities. However,
VFR flight conditions should return by mid to late morning. Some
ceilings around 5 kft which are the remnants of convection that
occurred farther northwest over Oklahoma during the previous
evening should move eastward today affecting areas north of
Interstate 20. Elsewhere, scattered daytime cu are also expected.
Increasing low-level southerly flow may advect low clouds and fog
northward late in the period resulting in more MVFR/IFR flight
conditions.

CN

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  94  73  93  76 /   0   0   0   0
MLU  92  70  91  72 /   0   0   0   0
DEQ  91  68  90  72 /  10   0   0  10
TXK  92  71  92  75 /  10   0   0   0
ELD  91  69  91  72 /   0   0   0   0
TYR  90  72  91  75 /   0   0   0   0
GGG  92  71  91  75 /   0   0   0   0
LFK  92  71  93  75 /   0   0   0   0

&&

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

$$

SHORT TERM...13
LONG TERM....13
AVIATION...09