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FXUS64 KSHV 231324
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
724 AM CST Sat Feb 23 2019

.AVIATION...

A warm front continues to push northward across the region this
morning. Ahead of the warm front, dense fog is prevailing mostly 
north of a line from KLFK to KSHV to KMLU. At the same time 
strong to severe thunderstorms will develop and move eastward across
the terminals through noon. Visibilities and ceilings will drop 
flight conditions down to MVFR/IFR/LIFR for most locations. Flight
conditions will improve behind the convection as it moves eastward but
southwest winds 15-20 mph with gusts near 30 mph will move into 
the region. A cold front will eventually move across the region 
late this evening and winds will shift to the northwest. /20/

&&

.PREV DISCUSSION... /issued 537 AM CST Sat Feb 23 2019/ 

SHORT TERM.../Today through Sunday/

A complex forecast is in store for the region today. First thing
first, a warm front continues to slowly move northward over the
area. Its currently located along a line from Hemphill Texas to
Jena Louisiana. Along and north of the front, Dense Fog continues
to develop across the region. Decided to extend the Dense Fog
Advisory as far north as the Interstate 30 corridor until 9am to 
account for this trend. In addition to the fog, our well advertise
severe weather threat still looks possible. The previous mentioned
warm front is expected to continue its slow push northward before
stalling and mixing out along a line from Lufkin Texas to
Shreveport Louisiana to Magnolia Arkansas. Warmer and more humid
air will move into areas south of the warm front. At the same 
time a longwave trough will become negatively tilted as it 
continues to eject into the TX/OK Panhandle region. The trough and
associated cold front will rapidly push towards the region today.
Ahead of the front, a pre-frontal trough will develop over east 
Texas near sunrise. As the pre-frontal trough shifts eastward, 
large scale forcing will develop resulting in a broken line of of 
convection across East Texas. The convection will begin to 
intensify as in gets into the area south of the aforementioned 
warm front, where mid level lapse rates will approach 8.5 C/km 
along with effective bulk shear near 60 kts and Cape values over 
1000 J/kg. Freezing levels should also be below 13 kft along with 
plenty of buoyancy around -20 C. These parameters should yield an 
environment primed for severe weather. The Storm Prediction Center
has issued a slight risk for areas generally east of a line from 
Lufkin Texas to Hope Arkansas, with an Enhanced Risk east of a 
line from El Dorado Arkansas to Columbia Louisiana. The broken 
line should eventually consolidate into a MCS as it rapidly 
advances eastward across the region. Damaging wind gusts, large 
hail, and isolated tornadoes will be possible with this line along
with some brief heavy rain. Can't rule out some localized flash 
flooding in some of the stronger storms, especially across south- 
central Arkansas and north-central Louisiana, where 2-3 inches of 
rain has has occurred over the past couple of days. The convection
should move out of the region by mid afternoon today. Gusty 
southwest winds 15-20 mph will move into the region, with gusts as
high as 30 mph. A Lake Wind Advisory will likely be issued by mid
morning to account for this. Highs today may approach the mid to 
upper 70s today as strong dry southwest winds typically yield warm
temperatures across the region. The trough and associated cold 
front will move through the region by midnight tonight bringing 
much cooler and drier air. Overnight lows will fall into the upper
30s to low 40s across most of the region. A much drier and cooler
day expected Sunday with mostly clear skies and highs near 60 
degrees. /20/

LONG TERM.../Sunday Night through Saturday/

The drying trend continues into early next week with near zonal flow 
noted in the mid levels of the atmosphere. That flow does become 
slightly southwest by Tuesday with good model consensus now of some 
light precipitation possible in the Tue thru Friday timeframe. 
Temperatures during this time frame will be near normal for late 
February with no real cold air to speak of. 

As we move into late next week into next weekend, medium range progs 
diverge with the GFS bringing a surge of cold air into the Southern 
Plains late Friday into Saturday with the aid of a 1040mb sfc ridge 
moving into the Central Plains. The Canadian is similar but delays 
this shot of cold air until just beyond this forecast period and the 
ECMWF is even slower than that. Needless to say this cold air will 
be a change from next weeks pattern whenever it arrives and will be 
watched closely in future model runs. 

13


&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  73  42  60  36 /  90   0   0   0 
MLU  77  44  60  36 /  90   0   0   0 
DEQ  70  36  58  30 /  60   0   0   0 
TXK  72  38  58  34 /  70   0   0   0 
ELD  73  40  59  30 /  90   0   0   0 
TYR  71  40  60  37 /  60   0   0   0 
GGG  72  40  60  37 /  70   0   0   0 
LFK  73  42  63  38 /  90   0   0   0 

&&

.SHV WATCHES/WARNINGS/ADVISORIES...
AR...Dense Fog Advisory until 9 AM CST this morning for ARZ059>061-
     070>073.

LA...Dense Fog Advisory until 9 AM CST this morning for LAZ001>006-
     010>014-017>019-021.

OK...None.
TX...Dense Fog Advisory until 9 AM CST this morning for TXZ096-097-
     108>112-124>126-136>138-149>153-165>167.

&&

$$

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