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fxus64 kshv 202106 

Area forecast discussion
National Weather Service Shreveport la
406 PM CDT sun Oct 20 2019

Short term.../tonight through Monday night/

Despite an abundance of low clouds and patchy fog this morning,
temperatures have climbed well into the 80s this afternoon. Some
areas along and south of I-20 have even managed the upper 80s for
highs as a warm front has shifted north today. In addition, dew
points have also surged into the lower 70s across much of these
same areas. This is all occurring ahead of a cold front which is
primed to move into our northwest zones around midnight and quickly shift
southeast across the region overnight through Monday morning, setting the
stage for a potential severe weather event across our entire
four-state region. Although low-level instability may initially
decrease slightly after sunset, expect it to increase once again
with the approaching cold front as MUCAPE values spike toward the
2000-2500 j/kg range overnight and perhaps a bit higher in some
locations. Add in the increasing low-level jet in the range of
50-60 kts and veering wind profiles with increasing wind shear, a
very robust line of convection will develop and spread southeast toward
the I-30 corridor where an enhanced risk of severe weather is
noted in the Storm Prediction Center day 1 outlook. This line will continue on to the
southeast across the remainder of the region with a primary damaging wind
threat coupled with the lower threats of large hail and isolated
tornadoes, which would likely be embedded within the evolving
qlcs. Rainfall amounts will average near an inch across the region
with isolated higher amounts possible over the next 24 hours.

The line of convection should exit the region by early to mid
afternoon on Monday with cooler and drier spilling south across
the region. Highs on Monday afternoon will range through the 70s
while overnight lows will fall into the 40s to near 50 degrees in
wake of the cold front on Monday night under clear skies and light
northwest winds.


Long term.../Tuesday through Sunday night/

A departing trough of low pressure extending from the Great Lakes
into the lower miss valley on Tuesday will result in milder
temperatures and drier conditions through at least Wednesday. By
Thursday, the westerlies will remain rather active as yet another
trough of low pressure moves out of the intermountain west and into
the Great Plains. Low level moisture should increase quickly Wed
night into Thu with perhaps some diurnally driven isolated to
scattered convection possible across our western half on Thursday
and then chance pops areawide Thu night into Friday.

There continues to be considerable discrepancies concerning how this
late week trough will evolve with the European model (ecmwf)/Canadian solutions
suggesting the base of the trough will cut itself off from the
westerlies on Friday in the Lee of the southern rockies while the
more progressive GFS suggests the trough will be much more open and
quickly brings an end to the rainfall across our area on Friday. The
differing solutions remain dug-in in regards to the above features
so tried to blend the varying solutions which would result in rain
chances lingering at least into the first half of Saturday.
Regardless, look for much cooler conditions with a frontal passage
sometime late Thursday or Friday with a cool upcoming and possible
wet first half of next weekend.



Previous discussion... /issued 1257 PM CDT sun Oct 20 2019/


For the 20/18z taf period, flight conditions continue to improve
as lower cigs lift/clear with VFR now at our East Texas terminals
and shv while MVFR/IFR conditions linger at txk/eld/mlu into the
early afternoon. However, these sites are expected to go VFR in
the next hour or two as a warm front continues to lift northeast.
Convection will be very isolated through the remainder of today
but begin to increase later tonight ahead of a cold front. Strong
to possibly severe convection will follow overnight through early
Monday along the front with a solid line of thunderstorms expected
to develop with strong and gusty winds spreading southeast across
all sites through Monday morning. In the meantime, winds will be
generally around 10 kts or less from the S/SW ahead of the front
and then quickly veer north/northwest with fropa as speeds increase to near
15-20 kts with higher gusts, especially invof of the front/along
the line of convection. Cigs/vsbys will also deteriorate quickly
as this convection advances across the region on Monday morning,
likely prevailing MVFR/IFR through the end of the taf period.



Preliminary point temps/pops...
shv 69 77 50 74 / 80 80 0 0
mlu 71 77 50 74 / 30 90 10 0
deq 60 73 41 72 / 90 20 0 0
txk 64 73 46 72 / 90 50 0 0
eld 68 76 46 72 / 70 80 0 0
tyr 63 74 48 74 / 90 40 0 0
ggg 66 74 47 73 / 80 50 0 0
lfk 71 78 50 77 / 70 80 0 0


Shv watches/warnings/advisories...

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