Area Forecast Discussion
Issued by NWS Shreveport, LA

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494
FXUS64 KSHV 221216
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
716 AM CDT Fri Jun 22 2018

.AVIATION...
For the 22/12Z TAF period, a mixed bag of flight categories this
morning with mostly MVFR/IFR cigs as low stratus deck continues
to overspread area terminals. The cigs will gradually lift into a
cu field later today with VFR conditions returning areawide by
late morning toward midday. Convection will begin to increase
across south Arkansas and north Louisiana this afternoon through
this evening, and possibly extend farther west into east Texas
along the I-20 corridor. The best odds for SHRA/TSRA continue to
favor the ELD/MLU/SHV/TXK sites due to the stronger forcing with
a shortwave shifting SE along a stalled frontal boundary near the
I-30 corridor. Stronger storms will have the potential to produce
heavy downpours, hail, gusty winds, and frequent lightning. S/SW
winds around 10-12 kts with higher gusts will aid in Gulf moisture
transport and result in low stratus returning overnight and MVFR
cigs affecting most sites prior to the end of this TAF period at
23/12Z.

/19/

&&

.PREV DISCUSSION... /issued 431 AM CDT Fri Jun 22 2018/

SHORT TERM.../Today through Saturday/

A warm and muggy start this morning is a precursor to a very hot
and humid day ahead with a frontal boundary perched along and near
the I-30 corridor. Convection is already ongoing this morning with
this stalled boundary with a weak shortwave impulse transitioning
along the middle Red River Valley. A much more potent upper level
shortwave is noted across the TX/OK panhandle region on the latest
water vapor imagery. This feature is what is likely to aid in the
development of much stronger convection later today through this
afternoon and into this evening. Moisture pooling along the front
coupled with rapidly increasing instability and unusually high
deep layer shear for this time of year will combine to produce an
increasing threat for severe thunderstorms, especially during the
afternoon and early evening as noted by the SPC Day 1 Convective
Outlook which places much of south Arkansas and north Louisiana in
a Slight Risk where the greatest forcing appears to reside today.
The remainder of the region is in a Marginal Risk, and the full
suite of severe weather possibilities will be in play to include
isolated tornadoes with a S/SW propagating line of thunderstorms,
which seems to be best handled by the latest 06Z run of the NAM.
The threat should quickly diminish as we approach midnight with
any lingering convection shifting south of the I-20 corridor in
the mid to late evening hours.

As the stalled frontal boundary begins to lift back northward on
Saturday, temperatures will continue to climb higher this weekend
and rain chances will be dropping over much of the region although
the north third of the area will still see a chance of additional
showers and thunderstorms with another series of upper shortwaves
transitioning E/SE from the Plains. However, severe weather does
not appear to be as much of a threat Saturday compared to today.
The bigger story will be the heat and increasing potential for a
heat advisory as heat index values approach or exceed 105 degrees.
Although a few areas may be close today, better chances of seeing
this criteria met across a broader area will come over the weekend
so stay tuned for any potential heat advisory headlines over the
coming days as upper level ridging returns across the region and
rain chances become greatly diminished.

/19/

LONG TERM.../Saturday Night through Friday/

Weak shortwave energy across the Middle Red River Valley of
Southeast Oklahoma, Northeast Texas into Southwest Arkansas will be
sliding eastward Saturday Night into early Sunday and will likely be
the trigger necessary for scattered convection. It does not appear
at this time that the convection will make it as far south as the
I-20 Corridor but will continue to watch this possibility for the
weekend with future forecasts.

Beyond Sunday, weak upper ridging will continue building across our
region of the country through early next week. By Tuesday, the
southern end of an upper level trough across the Central Plains will
try to clip our region Tuesday into Wednesday but Medium Range progs
do not hold out much hope for precipitation so have left that
possibility out for now. In the wake of this trough, a stronger
ridge of high pressure will build into the Southern/Central Plains
and will likely expand eastward, encompassing the the Mid
Mississippi Valley by the end of the upcoming work week. If this
pattern holds, it will result in virtually no chances for rainfall
and hot temperatures through the extended periods.

Concerning temperatures, stayed close to MOS overnight Min temps
through the extended but bumped up MOS daytime highs through the
extended given the strengthening ridge of high pressure developing
by the middle and latter half of next week.

13

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  95  77  95  76 /  30  20  10  10
MLU  91  75  93  75 /  60  20  10  10
DEQ  92  74  93  74 /  30  40  30  40
TXK  92  77  93  76 /  40  30  20  30
ELD  90  76  93  75 /  60  30  20  20
TYR  96  75  94  76 /  20  20  10  10
GGG  95  76  95  75 /  20  20  10  10
LFK  94  76  94  76 /  10  10  10  10

&&

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

$$

19/13



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