Scientific Forecaster Discussion
fxus64 kshv 240414
Area forecast discussion
National Weather Service Shreveport la
1114 PM CDT Fri Jun 23 2017
quick zone update just sent to make a few minor adjustments to
pops tonight. The gust front from the earlier Arkansas mesoscale convective system continues to
makes steady progress SW across NE Texas/north la attm, with additional
sct strong to occasionally svr convection developing along this
gust front as it intersects a weak sfc front extending across North Texas
just north of the dfw metroplex east to just S of prx to near txk, and
extreme nrn la, where it has been convectively reinforced from the
earlier mesoscale convective system. The air mass remains quite unstable ahead of the
ongoing bndrys where sbcapes of 3000-4000+ j/kg remains present
across much of East Texas/wrn la. However, weak mid level winds and and
the lack of deep lyr forcing should keep this convection loosely
organized, with the initial shortwave driving the earlier Arkansas mesoscale convective system
having already dropped southeast across the Delta Region/lower MS valley
where the air mass is more stable. However, the short term progs
do hint at additional development occurring overnight across the
middle Red River valley as a second shortwave noted on the
evening water vapor imagery over West Texas/cntrl OK helps to initiate
additional sct/numerous convection as it spreads southeast across the
region. The only fly in the ointment is the fact that how much
instability will remain and whether the existing gust front/cold
front slow overnight, but could help to focus additional
convection as forcing increases late with the approaching
shortwave. The short term progs remain all over the place with
where/how much convection will develop as only the 18z NAM
actually initialized best on the Arkansas MCS, with the hrrr playing
catchup all night and also lacking convective development over
much of East Texas. However, believe the svr threat will remain isolated
given the weak overall forcing and especially as the gust front
continues to propagate SW and cool/stabilize the air mass.
In the update, did lower pops to chance across southeast OK/SW AR, but
maintained likely pops over much of East Texas/north la with the ongoing
convection. Did not make any changes to forecast min temps, but
will be dependent on the gust front/sfc front passage.
Grids will be available shortly.
Previous discussion... /issued 727 PM CDT Fri Jun 23 2017/
for the arklatex, VFR for now, but a convective complex is looming
to our north from near kdeq to kllq in Arkansas. This feature will have
life potentially all night as a cold front is draping in as well.
This ts activity will likely be affecting Arkansas sites and perhaps la
tafs as well during the late evening and early morning. The cold
front will filter north/NE low level winds just as the morning stratus
is lifting after daybreak and may crop up some early convection.
Improvements back to VFR may take time in the afternoon on Sat.
Preliminary point temps/pops...
shv 74 82 69 85 / 60 70 30 30
mlu 74 82 69 85 / 60 70 20 20
deq 69 82 62 85 / 40 40 10 10
txk 71 80 65 84 / 50 60 20 10
eld 71 81 64 85 / 50 60 10 10
tyr 75 83 68 85 / 70 70 40 40
ggg 73 82 68 85 / 70 70 40 30
lfk 76 86 71 85 / 50 70 50 60