Area Forecast Discussion
Issued by NWS Shreveport, LA

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515
FXUS64 KSHV 081206
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
606 AM CST Thu Dec 8 2016

.AVIATION...
For the ArkLaTex, IFR/MVFR cigs and some vsby with -ra/dz will
all be assuming VFR. An Arctic cold front has moved through with
gusty N/NE winds 10-20KTS. Low levels are N/NE 20-30KTS up to
4-5kft, then slack and back to West by 7kft with increasing
Westerlies flow with 50KTS at the freezing level and 70-100KTS
into upper flight levels. The low clouds are drying in the wind,
but VFR cigs will linger all day as a short wave in the pattern is
over El Paso and is moving E at 50KTS. Next rain late weekend. /24/

&&

.PREV DISCUSSION... /issued 348 AM CST Thu Dec 8 2016/

DISCUSSION...
A longwave trough progressing east towards the middle to upper
Mississippi Valley early this morning, has sent down a cold front
which was seen on radar moving south nearing the I-20 corridor at
09Z. Thus, areas once plagued with fog across southeast OK and
southwest AR has scoured out given the slightly breezy northerly
cold front ushering in a drier airmass /dewpoints have fallen into
the 20s and 30s/, but bkn-ovc skies persisted. South of the front, a
stratus deck accompanied by periods of drizzle/light rain were the
main weather features. The HRRR and NAM hints at this precip
activity shifting south of the FA by mid-late morning due to the
impingement of the cold front and drier air entrainment. The 1045
mb sfc ridge across KS is driving the cold front, and producing
pressure rises on the order of 4-6 mb per 3 hours, hence northerly
wind speeds have increased into the 10-14 kt range /with 15-20 kt
gusts/ behind the front, with breeziest conditions noted across
east TX. Models suggest such speeds will ensue throughout the day
/so will hold off on a Lake Wind Advisory attm/, and finally ease
up shortly after sunset as the gradient relaxes. The CAA is
commencing to slowly ooze in across the northern zones, evident by
temps dropping 3-4 degrees in the last 4 hours, but the cold air
will make its presence known soon enough, starting with temps
this aftn not looking much different from what is occurring
currently /upper 30s north to middle 40s south/.

Tonight, with wind speeds relaxing, skies clearing and 850 mb temps
dipping to between 0C to -5C, excellent radiational cooling will
take place and the cold air will definitely garner your
attention. We will see temps range from the upper teens across
southeast OK and portions of southwest AR to lower to middle 20s
elsewhere, which is nearing Hard Freeze criteria. Due to this air
being the coldest we have seen since the Winter of 2015 here are a
few reminders: cover exposed pipes, bring pets indoors if possible
and cover sensitive vegetation.

The sfc ridge and associated CAA will start to shift east of the
region on Friday, but it will still have a grip on the Four-State
region with temps in the 40s and Friday night temps in the 20s. A
southerly sfc wind will make a return on Saturday, thus temps will
rebound into the 50s and 60s by late weekend-early next week. We may
get another shot at drizzle/light rain late weekend into early next
week, courtesy of a couple of eastward propagating ul disturbances
to our north. However, this progressive pattern will get interrupted
by yet another cold air dump, exhibiting to occur by mid-late week
of next week. How cold will the airmass be, is a bit hard to say
this far out in advance, however guidance suggesting daytime
temps in the 40s and overnight temps in the 20s to lower 30s seems
reasonable attm.

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  43  25  43  27 /  20   0   0   0
MLU  45  24  42  25 /  30   0   0   0
DEQ  39  18  41  23 /   0   0   0   0
TXK  41  20  40  25 /  10   0   0   0
ELD  42  20  41  22 /  20   0   0   0
TYR  41  23  44  29 /  20   0   0   0
GGG  42  23  44  27 /  20   0   0   0
LFK  47  25  48  28 /  30   0   0   0

&&

.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&

$$

24/29



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