Area Forecast Discussion
Issued by NWS Shreveport, LA

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FXUS64 KSHV 222341

Area Forecast Discussion
National Weather Service Shreveport LA
641 PM CDT Fri Sep 22 2017

Isolated showers have dissipated across portions of North Central/
Northeast Louisiana with VFR conditions expected to prevail
through the evening hours. Conditions should begin deteriorating
in the form of patchy dense fog and IFR/LIFR ceilings across area
terminals after midnight through the mid morning hours on Sat. The
worst fog potential will likely be across the MLU/LFK/GGG
terminals with low ceilings likely at those terminal in addition
to the TYR terminal. Otherwise, IFR/MVFR ceilings will be possible
shortly after sunrise at the remaining terminal locations for at
least a couple hours through mid morning before ceilings scatter
out and fog lifts areawide on Saturday by mid to late morning. VFR
conditions should prevail beyond 17z on Sat through the afternoon



.PREV DISCUSSION... /issued 314 PM CDT Fri Sep 22 2017/

An UA ridge draped from the Great Lakes region southwest to
across the majority of the Four-State Region has led to sea-breeze
convection having a tough time making it to the region /versus
what we have seen the last several days/. Only a few isolated
showers were nearing/moving across Deep east Texas late this
afternoon. However, a weak shear axis on the eastern periphery of
the aforementioned UA ridge have aided in developing isolated
showers across northeast LA and southwest AR, nearing Monroe LA
and Texarkana AR respectively. Per radar analysis, the precip
activity across all locations were not strong at all /which is not
surprising given lack of UL support/ and per the HRRR solution,
will diminish shortly after sunset. Furthermore, 21Z metars
reported temps in the lower 90s, making it unseasonably warm for
the first day of the Fall season. Tonight, clear skies, light
southerly winds and moist sfc conditions /dewpoints in the 60s
and 70s/ will result in another round of patchy fog mainly along
and south of the Interstate-20 corridor. Portions of east TX and
deep east TX may once again experience patchy dense fog, though
confidence is not high enough to issue a Dense Fog Advisory attm.
Will let later shifts see if dense fog comes into fruition.

Slightly better chances for isolated to scattered showers and
thunderstorms will occur this weekend, courtesy of a westward
drifting weak UA disturbance, originating from the southeast
CONUS. This disturbance providing for a bit of UL support will
interact with a relatively moist low level atmosphere as southerly
sfc winds ensue /PWATs on the order of 1-1.50 inches/. Attm, do
not expect storms to reach strong levels given the that the
disturbance is not overly strong by any means. This general
weakness will remain nearby through Monday, before commencing to
shift east and wane significantly by Tuesday.

The eastward shift of the aforementioned weak disturbance is due to
a longwave UA trough translating east across the Rockies. Long term
solution hint at the longwave trough breaking into two defined
pieces: the northern periphery ejecting quickly northeast to across
the Northern Plains and into Canada by mid-week, whilst the southern
periphery progresses much slower eastward across the Desert
southwest/New Mexico Boot heel by late week. With a cold front
expected to impact the Four-State Region from northwest to
southeast on Wednesday, combined with a slow eastward propagation
disturbance to our west, will result in much better chances for
wetting rains initially across the northwest zones, then spreading
to the remainder of the area throughout the week. This welcomed
pattern change will result in daytime temps dropping from the
lower 90s down into the 70s and 80s, with overnight temps cooling
into the 50s and 60s by late week.



SHV  73  94  73  92 /  10  20  10  20
MLU  71  93  71  91 /  10  20  10  20
DEQ  69  92  69  91 /   0  10  10  20
TXK  71  92  71  91 /  10  10  10  20
ELD  70  92  70  90 /  10  20  10  20
TYR  72  92  71  92 /  10  20  10  10
GGG  71  93  70  92 /  10  20  10  20
LFK  71  93  71  92 /  10  20  10  20




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