Area Forecast Discussion
Issued by NWS Shreveport, LA

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203
FXUS64 KSHV 190929
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
429 AM CDT Thu Oct 19 2017

.DISCUSSION...
A shifting upper level pattern and returning southerly flow in the
low levels continue this morning as temperatures are running some
5-10 degrees warmer compared to 24 hours ago. Water vapor imagery
bears out this shift with an upper ridge axis now oriented east of
the Rockies down across the Southern Plains and into our region. A
weak shortwave is seen pivoting across the Rio Grande near El Paso
with abundant cirrus spreading across Texas into the western half
of our CWA. This thin cirrus will not have much effect on daytime
temperatures as highs will still manage the lower 80s areawide as
abundant sunshine is expected once again today. This warmer air
mass will also produce noticeably warmer overnight temperatures
compared to earlier in the week. Expect mid 50s to lower 60s for
lows on Friday morning with additional cloud cover moving in as
the shortwave feature translates farther east across Texas with
isolated convection developing prior to daybreak Friday morning.
The chance of isolated showers and even a few thunderstorms will
carry through the day on Friday across much of the region, but
better rain chances still await as we head into the weekend.

A tightening pressure gradient will develop by Saturday as low
develops east of Rockies as an upper trough swings out across the
Plains helping to advance a strong cold front eastward. This front
will shift toward our region late Saturday in an increasingly warm
and unstable environment which will be supportive of potentially
severe storms along a developing squall line east of I-35 from
eastern Oklahoma down into northeast Texas. The primary threat
with this line of storms will be damaging winds as is typically
the case with a linear storm complex with some bowing structures
possible within the line. Of course, these QLCS features can also
produce brief tornadoes so don`t want to completely rule out that
potential at this juncture. The current SPC Day 3 outlook does put
our NW zones in the slight risk area for Saturday evening with the
marginal risk area stretching a bit farther south and extending
from near Magnolia to Shreveport to Mount Enterprise. This severe
potential could extend into early Sunday morning, but we begin to
lose some of the instability and the overall threat appears to
weaken with time as the line of showers and storms shifts east
into southern Arkansas and northern Louisiana. The silver lining
with this system will be the beneficial rainfall so desperately
needed after weeks of very dry conditions. Rainfall amounts still
appear to be in the 1-2 inch range for most locations with higher
amounts possible along and north of the I-30 corridor.

Some guidance discrepancies remain in how quickly the trough will
exit the region as the EMCWF has reverted back to closing off a
low near DFW on Sunday evening resulting in a slower progression
through our region. Meanwhile, the GFS shows a low closing off as
well but well to the east along the MS River delta region with the
cold front departing our region by Sunday night into early Monday
morning and will continue to favor this faster exit for now until
better consensus is reached over the next few days. The remainder
of the extended period looks dry with cooler than normal readings
for much of next week in the wake of the cold front with longwave
troughing across the entire eastern half of the country.

/19/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  82  60  82  66 /   0  10  20  20
MLU  82  55  82  63 /   0   0  10  20
DEQ  81  54  80  62 /   0  10  20  20
TXK  81  57  80  64 /   0  10  20  20
ELD  81  54  80  63 /   0   0  10  20
TYR  82  62  81  67 /   0  20  30  30
GGG  82  60  82  66 /   0  20  20  30
LFK  83  63  80  67 /   0  20  30  30

&&

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

$$

19



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