Area Forecast Discussion
Issued by NWS Shreveport, LA

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FXUS64 KSHV 031059
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
559 AM CDT Mon Aug 3 2020

.AVIATION...

Very isolated, elevated showers in the VCTY of the ELD terminal,
otherwise high based cu field and/or low based AC field is
filtered across our airspace this morning. A cold front was
located near the I-30 Corridor at this time this morning as well
and as we go through the day, could see isolated to widely
scattered convection develop near and in the vicinity of this
boundary. Chances do not warrant a mention however. Otherwise,
should see winds come around to the northwest in the wake of the
boundary and north to northeast late tonight across our western
terminals. Look for increasing mid level cloud cover late tonight
across our western terminal airspace as well.

13

&&

.PREV DISCUSSION... /issued 324 AM CDT Mon Aug 3 2020/

SHORT TERM.../Today through Tuesday/

Pleasant conditions attm across the Four State Region but an
unseasonably strong upper trough axis remains entrenched across
our region this morning with northwest flow aloft noted along the
western flank of the trough. It`s this flow that is helping to
push a reinforcing shot of slightly cooler/drier air in the form
of a cold front which as of 07z was located just north and west of
the I-30 Corridor of NE TX into SE OK and SW AR. It`s this sfc
boundary and an elevated boundary north of this one around the
850mb layer, combined with a narrow tongue of higher PWAT near 1.5
inches oriented just downwind of both troughs that could help to
generate isolated to widely scattered pops today. The front will
help to taper temps somewhat across our northwest zones but kept
temps pretty much on the persistence side of things ahead of the
frontal boundary as compressional warming ahead of the boundary
cannot be ruled out but looks rather negligible.

Overnight, kept isolated to widely scattered pops into the early
evening hours generally just south of the I-20 corridor across NE
TX and near the corridor across NW LA but by this time, winds
should veer around to the northwest even ahead of the sfc
boundary which should limit sfc frontal forcing with the boundary
likely near a LFK/MLU line by 00z this evening. Stayed close to a
NAM/GFS MOS blend concerning overnight temps with lows as cool as
the lower/middle 60s across the Ouachitas of SE OK into SW AR.
Late tonight, will need to watch for a weakness aloft in northwest
flow that coincides with 700mb thetae ridging which could result
in some nocturnal convection across our western third after
midnight into the morning hours on Tuesday. The NAM/CMC is much
more in favor of this convection developing vs the operational
EC/GFS but having said this, decided to add slight chance pops
across our western third to account for this possibility.

Assuming we do see isolated to widely scattered convection across
our western third late tonight, held this over in the pop
department for the first half of Tuesday, limiting pops back to
our southwest third only for Tuesday afternoon.

13

LONG TERM.../Tuesday Night through Sunday Night/

The beginning of the long-term period will find our region in a
pattern more typical of early to mid June characterized by
northwesterly flow aloft with a longwave trough over Eastern North
America and an upper ridge over the Desert Southwest, which will
gradually move east with time. A shortwave trough embedded in the
flow will round the top of the ridge and slowly move southeast
toward the Lower Mississippi Valley. This trough should help to
initiate a convective complex over the High Plains of Eastern
Colorado. The thunderstorms should ride the gradient of a 700 hPa
theta-e axis southeast towards the region. Compared to previous
model runs, the upper ridge is more amplified and less flat, which
keeps the shortwave and the convective complex farther southwest and
closer to our area. The thunderstorms should be weakening as they
approach the forecast area, but slight chance to low-end chance PoPs
are still warranted for Southeast Oklahoma, much of East Texas, and
portions of Southwest Arkansas for Wednesday morning.

A similar situation should occur Thursday morning, but rain chances
should be slightly higher as convective initiation should occur over
Eastern Oklahoma, and the storms will have less distance to travel
to reach us. However, with the shortwave trough southeast of the
area, the decreased vertical ascent could hinder how much
development occurs. Severe weather is not anticipated, but depending
on the evolution of any potential MCSs are the development of any
bowing segments, an isolated damaging wind threat could be in play.

By Thursday afternoon, the upper ridge will centered directly over
Texas and will be expanding over our area. Rain chances will become
primarily limited to daily showers and thunderstorms associated with
the sea-breeze south of Interstate 20 each afternoon through the
remainder of the extended. Unfortunately, that also means the heat
and humidity will build. Daytime high temperatures should be well
into the mid 90s for most locations by the end of the weekend, and
heat index values could easily be over 105 degrees F.

CN

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  92  69  90  71 /  20  20  10  10
MLU  93  68  89  67 /  20  20  10   0
DEQ  88  63  87  66 /  10  10  10  20
TXK  87  66  87  68 /  10  10  10  10
ELD  89  64  87  66 /  20  10  10   0
TYR  92  70  92  72 /  20  20  20  10
GGG  92  69  91  71 /  20  20  20  10
LFK  95  70  94  73 /  20  20  20   0

&&

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

$$

13/13/CN



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