Area Forecast Discussion
Issued by NWS Shreveport, LA

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FXUS64 KSHV 241136 AAA
AFDSHV

Area Forecast Discussion...UPDATED
National Weather Service Shreveport LA
636 AM CDT Mon Apr 24 2017

.AVIATION...
VFR conditions will continue through the 24/12Z TAF period. Sfc
ridging anchored over the region this morning will gradually shift
E of the area this afternoon and evening. Should begin to see a
bit of an increase in thin cirrus by afternoon over E TX, and
possibly over the remainder of the region this evening. Lt/Vrb
winds this morning will become S 4-7kts after 18Z over E
TX/extreme SW AR/Wrn LA. Winds will begin to increase late tonight
to 10-12kts over E TX, although MVFR cigs should not affect the
TYR terminal until just beyond the 12Z TAF period. /15/

&&

.PREV DISCUSSION... /issued 351 AM CDT Mon Apr 24 2017/

DISCUSSION...
Clear skies early this morning and rather light/calm sfc winds
courtesy of a sfc ridge practically overhead has lead to temps
dropping into the 40s CWA wide per 08Z metars. Before sunrise, would
not be surprised to see temps near/equate the upper 30s particularly
across portions of southeast OK and southwest AR. Aloft, a flattened
UA ridge will progress eastward across the Four-State Region today,
whilst the sfc ridge pushes east and sfc lee troughing aids in
returning sfc winds to a srly flow. As a result, will see temps warm
into the upper 70s to lower 80s.

The dry airmass we have experienced the last few days due to the
fropa will take a little while to recover, with a notable surge in
PWATS anticipated to occur by tomorrow /0.75-1.15 inches/ due to a
persistent upslope sfc regime. Concurrently, an UA trough will be
pushing east-southeast to across the Four-Corners region thus
veering near zonal flow aloft to the southwest, as well as deepening
sfc lee troughing resulting in a tightened pressure gradient and
subsequently, breezy southerly winds that may equate Lake Wind
Advisory criteria tomorrow aftn.  As the said disturbance draws
near, the atmosphere continues to recover from the dry airmass with
top-down moistening noted per progged model soundings and hence,
PWATS increasing to between 1.40-1.60 inches by Wednesday morning,
which is perfect timing as the said disturbance is poised to move
across the region on Wednesday. Precipitation will be focused along
a cold front that will impinge on the region from west to east, and
with MUCAPE of 2000-2500 j/kg and 0-6 km bulk shear of 30-60 kts,
this suggest some of the storms could become strong to severe, with
hail and damaging wind gusts being the primary threats. However,
can not rule out an isolated tornado or two, given low LCL/s and
progged hodographs exhibiting low level curvature. Furthermore,
model solutions hint at moderate rainfall with the Weather
Prediction Center showing rainfall amounts of 1.00-1.25 inches
mainly north of the Interstate 20 corridor, but if the activity
evolves into a line of storms, moderate rainfall could occur just
about anywhere. It is therefore not surprising to see that the
Storm Prediction Center now has a Slight Risk of severe storms on
Wednesday across portions of east TX, deep east TX, northern LA
and all of southwest AR.

The fropa will dry out the atmosphere by Thursday but it will make a
quick recovery by Friday, just in time for the next potential severe
wx maker. Uncertainty amongst the long term solutions still exist as
the ECMWF is slightly slower and has the center of the
disturbance much farther north than the slower GFS. Keeping in
mind that the fine details still needs to be ironed out, may see
showers and thunderstorms develop ahead of the system along and
north of a warm front on Friday, which could near our northern
zones. The main convection is expected to occur along a cold front
from west to east commencing Saturday night. Once again, the
severe indices are indicative of storms having the potential of
becoming severe /MUCAPE > 2000 j/kg and 0-6 km bulk shear of 30-50
kts/ with an additional threat of moderate to heavy rainfall.
Thereafter, quiet wx will ensue and temps will be slow to warm
above the 70s. /29/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  80  55  86  68 /   0   0  10  10
MLU  78  52  84  64 /   0   0   0  10
DEQ  78  51  85  66 /   0   0   0  20
TXK  78  55  85  67 /   0   0   0  20
ELD  79  50  83  66 /   0   0   0  10
TYR  79  59  87  69 /   0   0  10  20
GGG  79  56  87  69 /   0   0  10  10
LFK  80  58  87  71 /   0   0  10  10

&&

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

$$

15


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