Area Forecast Discussion
Issued by NWS Shreveport, LA

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663
FXUS64 KSHV 160452 AAA
AFDSHV

Area Forecast Discussion...UPDATED
National Weather Service Shreveport LA
1052 PM CST Mon Jan 15 2018

.DISCUSSION...
Overall, very few changes were made to the forecast. Cold air is
rapidly sinking south across the area, and at 0430z, the leading
edge of the wintry precip appears to be near a line from Bullard
TX, to Gladewater TX, to Rodessa LA, to between Arkadelphia AR and
Camden AR. So far, the event has unfolded just a bit slower than
anticipated. However, cold air advection should increase during
the overnight hours as northerly winds also increase in speed and
become quite gusty. Precip coverage and intensity should also
increase after midnight as a large scale ascent increases ahead of
an approaching vort max that is still well to the north. No
changes were made to expected snowfall or ice accumulations. Wintry
precip should begin to affect the Shreveport- Bossier City area
between midnight and 2 AM CST.

The gusty north winds combined with the cold air will result in
wind chill values falling into the single digits across much of
the area tonight and even below zero across portions of McCurtain
Country and the terrain of Southwest Arkansas. The north winds
will also increase to above 15 kts with gusts as high as 25 kts
for much of the area. Therefore, a Wind Chill Advisory and Lake
Wind Advisory were also added to mix for this event.

/09/

&&

.PREV DISCUSSION... /issued 539 PM CST Mon Jan 15 2018/

AVIATION...
A cold front will move across the region overnight with north
winds increasing to around 15 kts with higher gusts behind it.
Rain behind the cold front will transition to a -ra/sn/pl mix by
16/06Z followed by prevailing -sn through daybreak. Snow to
gradually diminish by 16/18Z. Otherwise, IFR ceilings expected
across area terminals overnight, gradually improving during the
day Tuesday. /05/

PREV DISCUSSION... /issued 416 PM CST Mon Jan 15 2018/

DISCUSSION...
Our much anticipated winter weather event is imminent now as the
strong Arctic air mass is already beginning to spill south along
the I-30 corridor with the much warmer air still in place farther
south where we have climbed into the lower 60s over much of east
Texas and north Louisiana. However, these temperatures will soon
go by the wayside as this Arctic front rapidly sweeps through the
rest of the region this evening through the early Tuesday morning.

Unlike most winter weather events, model solutions have been very
consistent in a rapid cooling through the entire atmosphere such
that a transition from rain to snow will occur quickly with only a
small window of opportunity for any wintry mix which would likely
include sleet and much less chance of freezing rain. As the quick
transition to snow takes place, heavier bands are expected to line
up generally along and between the I-30/I-20 corridors where our
Winter Storm Warning takes affect at 9 PM tonight. These areas are
likely to see a broad swath of 3-4 inches of snowfall through the
first half of Tuesday before snow gradually tapers off from north
to south. To the immediate north and south of the warning, the
remainder of the CWA is only being included in a Winter Weather
Advisory due to lower forecast snowfall accumulations of generally
1-2 inches with isolated higher amounts up to 3 inches possible.
The northern advisory runs from 6 PM this evening through noon on
Tuesday, and the southern advisory begins later on Tuesday morning
at 3 AM and continues through 6 PM that evening.

Additional advisories and warnings will likely be forthcoming with
this Arctic air mass to include a Hard Freeze Warning and a Wind
Chill Advisory, but I have opted not to include these products in
this forecast package due to the other winter weather headlines
taking precedence.

As referenced above, the other major story aside from the wintry
precipitation will be the strong winds accompanying the front and
the bitter cold temperatures which will carry through the next 72
hours. In fact, daytime temperatures are not expected to get above
freezing on Tuesday which will create very hazardous travel
conditions as snow turns to slush on area roadways and then
quickly refreezes. This will be especially concerning on elevated
surfaces such as bridges and overpasses as well as less traveled
secondary roads. To make matters worse, temperatures will really
take a nosedive Tuesday night into Wednesday morning with lows in
the teens areawide. Due to this extremely low temperatures, highs
on Wednesday still may not get above freezing in some locations so
the travel woes will linger through Thursday in these areas where
additional refreezing will occur overnight Wednesday into Thursday
morning.

We will finally see some light at the end of the tunnel by late in
the week as much warmer temperatures will return on Friday through
the weekend ahead of another cold front. This next front will be a
Pacific front so temperatures are expected to remain well above
freezing with widespread showers and isolated thunderstorms likely
by Sunday with frontal passage. The front will clear the region
Sunday night and with a dry start expected for the new work week.

Thanks to all of our neighboring WFOs for the outstanding work and
collaboration today.

/19/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  24  29  15  33 / 100  70   0   0
MLU  25  28  15  32 /  90  80   0   0
DEQ  17  26  12  34 /  70  10   0   0
TXK  19  27  12  32 / 100  30   0   0
ELD  21  27  12  33 / 100  60   0   0
TYR  21  29  15  33 / 100  30   0   0
GGG  22  29  15  33 / 100  60   0   0
LFK  27  31  17  38 / 100  80  10   0

&&

.SHV WATCHES/WARNINGS/ADVISORIES...
AR...Winter Storm Warning until 6 PM CST Tuesday for ARZ059>061-
     070>073.

     Wind Chill Advisory until noon CST Tuesday for ARZ050-051-
     059>061-070>073.

     Winter Weather Advisory until noon CST Tuesday for ARZ050-051.

LA...Lake Wind Advisory until 9 AM CST Tuesday for LAZ001>003-010>014-
     017>022.

     Winter Storm Warning until 6 PM CST Tuesday for LAZ001>004-006.

     Wind Chill Advisory until noon CST Tuesday for LAZ001>004-010.

     Winter Weather Advisory from 3 AM to 6 PM CST Tuesday for LAZ005-
     010>014-017>022.

OK...Lake Wind Advisory until 9 AM CST Tuesday for OKZ077.

     Wind Chill Advisory until noon CST Tuesday for OKZ077.

     Winter Weather Advisory until noon CST Tuesday for OKZ077.

TX...Lake Wind Advisory until 9 AM CST Tuesday for TXZ096-108>111-
     124>126-136>138-149>153-165>167.

     Winter Storm Warning until 6 PM CST Tuesday for TXZ097-108>112-
     124>126-136>138-149>151.

     Wind Chill Advisory until noon CST Tuesday for TXZ096-097-
     108>112-124>126-136>138-149>153.

     Winter Weather Advisory from 3 AM to 6 PM CST Tuesday for TXZ152-
     153-165>167.

     Winter Weather Advisory until noon CST Tuesday for TXZ096.

&&

$$

09/05/13



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