Area Forecast Discussion
Issued by NWS Shreveport, LA

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FXUS64 KSHV 271128
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
628 AM CDT Sat May 27 2017

.AVIATION...
MVFR cigs will continue to affect most terminals through late
morning/early afternoon. Sly winds 10-15 kts with higher gusts
will help cigs to lift into the VFR. Cigs to lower once again
overnight, with wind speeds diminishing to around 10 kts after
sunset. A few tstms will be possible late in the pd, mainly across
our nrn areas, which could affect KTXK. Have opted for VCTS attm
due to uncertainty in timing and coverage. /12/

&&

.PREV DISCUSSION... /issued 330 AM CDT Sat May 27 2017/

DISCUSSION...
A rather moist low level atmosphere is quite noticeable early this
morning across the Four-State Region, as southerly sfc winds
maintain dewpoints in the 70s and a stratus deck blankets region
/temp-dewpoint depressions less than 5 degrees/. The stratus deck
will erode by mid-morning by high level cloudiness will remain in
its wake. Despite the cloud cover, daytime temps are still expected
to warm into the upper 80s /with a few lower 90s/. Attention will
quickly turn to an UA trough extending from an UA low across Canada
southwest to across the Southern Rockies. As the said disturbance
shifts east-southeast throughout today, its sfc counterpart  across
the Panhandles Region will also shift eastward to near the Red River
Valley this aftn and promote a slightly tightened pressure
gradient, leading southerly wind speeds of 10-15 mph /which is
below Lake Wind Advisory wind speed criteria/. It is interesting
to note that model guidance shows rather light QPF signals across
portions of the FA this aftn, which is likely overdone given a
strong capping inversion in place. However, an approaching cold
front from the northwest will aid in cooling temps aloft and thus
eroding the cap. Computer models hint at the front impinging
southeast OK and extreme northeast TX after midnight, between
27/09Z-27/12Z. An ongoing MCS/multi-cell storm complex exhibited
along the front will have the potential to move across the
aforementioned areas, and encounter a rather moist atmosphere,
MUCAPE values of 3000-4000 j/kg and 0-6 km bulk shear of 40-45
kts. This will raise concern for large hail and damaging wind
gusts. In addition, helicity values of 200-300 m2/s2 across the
northwest zones coupled with a frontal boundary suggests the
potential for isolated tornadoes. It is no wonder that the Storm
Prediction has an Enhanced Risk of severe storms across portions
of southeast OK and extreme southwest AR, with a Slight Risk of
severe storms portions of northeast TX, northwest LA, and
southwest AR. Keep in mind, the placement of the current Enhanced
Risk has shifted a tad north from earlier iterations due to model
solutions struggling a bit with the speed of the front thus, this
could change so be sure to stay abreast to the latest wx
information. Furthermore, locally moderate to heavy rainfall will
be possible with some of the thunderstorms activity.

The cold front will be slow to push southeastward throughout the day
tomorrow, and the MCS/multi-cell storm complex is progged to wane
during the morning hours tomorrow. Though additional isolated to
scattered showers and thunderstorms will not be hard-pressed to
develop during the aftn-evening due to a moist airmass in place,
frontogenetical forcing provided by the front and embedded impulses
within the west-southwest flow aloft resulting in increased UL
support. In fact model solutions agree that the best resurgence in
precip will occur late tomorrow aftn/early evening coinciding with
then when the aforementioned embedded impulses will arrive. Daytime
destabilization, the presence of a frontal boundary and MUCAPE of
2000-3000 j/kg will once again raise concern for strong to severe
storms, with large hail and gusty winds the main threats /deep
layer shear is progged to be rather weak so would think tornadoes
may be difficult to develop/. It is the reason as to why a Slight
Risk of severe storms for the entire CWA tomorrow is noted per the
Storm Prediction Center. The front will push just south of the
CWA tomorrow night, but will quickly retreat north back as a warm
front, thus maintaining an unsettled wx pattern throughout the
week. As such, each day next week will be plagued by cloudy,
rainy and subsequently cooler wx /daytimes temps dropping into the
lower to middle 80s/. /29/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  88  74  86  68 /  10  20  40  60
MLU  88  74  88  69 /  10  20  40  60
DEQ  87  71  82  60 /  10  60  30  20
TXK  87  72  83  63 /  10  50  50  50
ELD  86  72  83  64 /  10  30  40  50
TYR  89  74  85  67 /  10  20  50  60
GGG  89  75  85  67 /  10  20  50  60
LFK  91  77  89  71 /  10  10  30  70

&&

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

$$

12/29


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