Area Forecast Discussion
Issued by NWS Shreveport, LA

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000
FXUS64 KSHV 182346
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
646 PM CDT Mon Jun 18 2018

.AVIATION...
Isold convection across areas mainly near and north of I-30 will
diminish by sunset, along with south winds around 10 to 15 kts,
diminishing to 5 to 10 kts after sunset. Deep moisture will be on
the increase as juicy tropical air slowly movg nwd toward the
region, from a low riding slowly newd along the TX coast to near HOU
by late in the fcst cycle. Bands of convection will spread inland
to near the klfk terminal by early mrng, and spread nwd to near
I-20 by around 19/15-18z. Most tstm activity concentrated along
these banded features, with cells generally movg to the n/nw.
Heavy rain, gusty winds, and mostly mvfr cigs can be associated
with these bands of convection durg the day Tue./07/.


&&

.PREV DISCUSSION... /issued 334 PM CDT Mon Jun 18 2018/

SHORT TERM.../Tonight through Tuesday Night/

Outflow boundary that came northward from the coast early this
morning is currently across SC AR this afternoon and has squashed
a lot of the heating, instability across the northern half of LA
and as a result, convection has wained a bit. further to the south
and west, this is not the case as scattered showers and isolated
thunderstorms have been developing and this should continue to be
the case through the early evening hours, more so across the Lower
Toledo Bend and Sam Rayburn Country of Deep East Texas. This all
due in part to an elongated area of low pressure aloft which was
oriented southwest to northeast along the lower and upper Texas
Gulf Coast. This feature is forecast to move a little further
inland overnight into the day Tuesday across SE/Central and
Eastern Texas into NW LA and SW AR. This should result in slightly
higher coverage of showers with embedded thunderstorms across our
southwest half during the day Tuesday and have thus beefed pops
upwards accordingly. The cloud cover and increased rain chances
will also help to hold temperatures down somewhat on Tuesday with
daytime highs struggling to hit 90 degrees across most areas.

This weakness aloft will morph into an inverted trough of low
pressure late Tuesday into Tuesday Night and will pretty much
remain anchored across our region through at least early
Wednesday. Given the tropical-like airmass in place with PWATs
near 1.7 inches, you add a little heating and we should at least
see high scattered pop coverage across most of the region into
Wednesday.

13

LONG TERM.../Wednesday through Monday night/

As midweek arrives apparently so will more of the tropical moisture
out of the Western Gulf. Some of this tropical connection of higher
PWATS will be drawn Northeastward with the approach of an upper
trough in the Westerlies. The GFS and ECMWF agree on a surface
1021mb high pushing off the front range under the mid level trough
that will be edging out into the plains states. The surface high
soon melts away, but the upper trough spins up into a closed low
over NB on both models around 5750dam. This low continues to deepen
over KN by early Thursday and bottoms out at 5710dam while the ECMWF
only at 5740dam.

Either way, on paper the system looks occluded with a negative tilt,
but with the surface high gone and for this event at this time of
year it will mean a gathering of the tropical moisture for us
especially through late week. The WPC day 4 and 5 QPF are the most
helpful days, but the overall 5 day total has some 2 to 3 inches
possible from E TX into SW AR. For days 6 and 7 we zero out as the
low will lift away into the Great Lakes by late Friday and this will
essentially push the deeper moisture out of reach for us this
weekend. This will allow the Bermuda high aloft to bridge back
toward the Mexican upper high late in the period. So it will be back
to hot and dry pretty quick, but a nice reprieve of lower than
average highs will remain possible at least for the mid to late week
time frame.

/24/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  73  87  72  86 /  40  50  30  60
MLU  71  89  72  90 /  30  40  20  50
DEQ  71  88  70  83 /  20  40  30  60
TXK  71  88  71  83 /  30  40  30  60
ELD  70  88  70  83 /  30  40  20  50
TYR  74  85  73  84 /  40  60  40  60
GGG  73  87  72  85 /  40  60  40  60
LFK  73  83  74  86 /  60  70  50  60

&&

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

$$



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