Area Forecast Discussion
Issued by NWS Shreveport, LA
FXUS64 KSHV 220547
Area Forecast Discussion
National Weather Service Shreveport LA
1147 PM CST Sat Jan 21 2017
Showers increasing from the south and west late this evening and
those showers are helping to mix down some stronger winds across
our NE TX terminals at this time with southwest winds gusting
upwards of 30kts at times. East of this activity where skies have
cleared...dealing with visibility issues where vsbys have dropped
below 3 miles in a few locations. We should not have any ceiling
issues with the shower activity overnight and as the showers
spread north and east overnight...that should squash the limited
Upper trough moves ovhd on Sunday and with it...expecting to see
increasing convection across SE OK and SW AR with that activity
dropping southward towards the I-20 corridor during the afternoon.
Cannot rule out the possibility of isolated strong to severe
thunderstorms given the cold temperatures aloft passing overhead.
The other concern will be a very strong surface pressure gradient
in place ahead of and in the wake of a frontal boundary. Winds
will pick up from the WSW...shifting to the NW with sustained
winds of 15 to 20 mph with gusts upwards of 35 mph in a few
locations. Temporary low ceilings will be possible in the wake of
the cold front but kept them just above MVFR criteria for now.
.PREV DISCUSSION... /issued 941 PM CST Sat Jan 21 2017/
Tor watch in effect until 9 pm had to be extended until midnight
for north central La and extreme south central AR, as a persistent
band of stg to svr redeveloping tstms btwn I-20 and AR state line.
Also raised overnight lows a few degrees given continued cloud
cover and dew point trends./VII/.
PREV DISCUSSION... /issued 314 PM CST Sat Jan 21 2017/
A sheared and highly unstable atmosphere awaiting trigger for
convection to rapidly occur later this aftn. Special 18z soundings
at KSHV and KLZK showing dry adiabatic lapse rates in the 800-600
mb layer. Fairly lgt winds at sfc keeping low lvl shear at
moderately high lvls and suggesting primary threat to be very
large hail in storms, but still with existence of tornado and
damaging wind threat. Storm initiation expected within next hour
or two at the most...across se OK and extreme eastern TX, with
storms intensifying by early eve as they track across north LA
into sw AR. Commahead shape of this upper low as it wraps around
backside of low, will bring moisture swd back into area later
Sunday mrng. Low topped convection may occur with continued steep
mid lvl lapse rates beneath a stg upper lvl inversion. Low lvl
speed shear indicated in sfc westerly to nw wind veering profile.
Cold core low hail threat appear possible with this convection
although overall coverage will be low, should it materialize at
all. Cooler air finally movg into area with overnight lows back
into the 40s early next week, and mostly zonal flow suggest that
at least a few days of dry wx upcoming thru extended period.
.PRELIMINARY POINT TEMPS/POPS...
SHV 55 64 43 65 / 20 20 0 0
MLU 58 64 43 62 / 50 30 10 0
DEQ 51 60 37 61 / 20 30 0 0
TXK 54 61 40 62 / 20 30 0 0
ELD 55 62 40 62 / 20 30 10 0
TYR 54 63 43 66 / 20 10 0 0
GGG 54 63 42 64 / 20 10 0 0
LFK 56 65 43 67 / 20 10 0 0
AR...Lake Wind Advisory from 9 AM to 9 PM CST Sunday for ARZ050-051-
LA...Lake Wind Advisory from 9 AM to 9 PM CST Sunday for LAZ001>006-
OK...Lake Wind Advisory from 9 AM to 9 PM CST Sunday for OKZ077.
TX...Lake Wind Advisory from 9 AM to 9 PM CST Sunday for TXZ096-097-