Area Forecast Discussion
Issued by NWS Little Rock, AR

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FXUS64 KLZK 142340
AFDLZK

Area Forecast Discussion
National Weather Service Little Rock AR
540 PM CST Tue Nov 14 2017

.AVIATION...
An area of light precipitation continues to move through northern
AR at this time. A few showers will be possible this evening at
KBPK and KHRO along with MVFR to occasional IFR conditions. VFR
conditions are expected at the remainder of the terminals with
ceilings lowering with time. A cold front will move across all
the terminals except KLLQ during the period with winds shifting
to the NW in its wake. Only light amounts of precipitation and a
return to MVFR conditions are expected with this front.

&&

.PREV DISCUSSION...(ISSUED 255 PM CST Tue Nov 14 2017)
DISCUSSION...

Main concerns in this forecast cycle are chances of convection
each day of the week, any strong to severe storm threat late week
and into the weekend, then a temperature forecast with above and
below trends.

Currently an area of light convection continues to move east over
western AR and gradually weakens, then regenerates over northwest
AR. Short range models show low end lift moving over the area and
helping develop the light convection. Most rain amounts have been
less than a tenth of an inch. Mid and high clouds also continue to
stream in over AR from the west, and partly to mostly cloudy
conditions have been seen today. The cloud cover has held
temperatures below normal today, as well as some of the light
rain. Otherwise, surface high pressure is off to the east, and a
southeast wind flow has brought moisture levels up a bit, and as
and upper short wave system moves through the region and has
developed the light rain and showers. The forecast has had the
best rain chances over northern AR.

SHORT TERM...Tonight Through Thursday

Forecast will start with a low chance of light convection this
evening with weak lift. Later tonight, rain chances will focus
more over northwest AR, as a cold front and upper lift move
toward the southeast Plains. Good chances of showers with some
thunder on Wednesday, as the cold front and upper support move
through the region. Models vary on how far south the cold front
will drop in AR, but looks to be over southern AR where the front
will become stationary due to zonal flow. Then it will begin to
lift northward Thursday night as a warm front ahead of the next
storm system. Some rain chances will remain in the forecast as
this occurs. Lift is primarily seen over northern to western AR,
while the weakest over the south. Also, overall rain amounts will
be a few tenths to less than half an inch. Patchy fog will also be
seen late night to early morning. Temperatures will be around
normal values.

LONG TERM...Thursday night through Tuesday

The highlight of the long term forecast will be a cold front making
its way through the area this weekend.

The cold front that is expected to move through most of Arkansas and
stall out in the southern portions of the state will begin to lift
northward back through Arkansas on Thursday night and Friday, as
lower level high pressure to our northeast shifts surface winds out
of the south. The advancing warm front will keep slight rain chances
in the forecast and allow temperatures to jump into the upper 60s
and 70s for highs on Friday.

At this point we can take a look at the synoptic set up which will
be responsible for bringing another cold front through on Saturday.
At 00z Thursday, the upper level trough is forecast to be making its
way onto the pacific northwest`s shore.

The upper level trough which is associated with an upper level low
far to our north in Canada, will swing eastward through the plains
and impact the southeast by the Friday night/Saturday time frame. At
this point, the cold front looks to enter into the northwestern
portions of Arkansas overnight Friday or early Saturday morning, and
eventually pass through the state by Saturday evening/Sunday
morning.

Overall forcing with this system has remained relatively steady from
the 00z to 12z run of the GFS, but the model has trended closer to
the ECMWF. However, the ECMWF continues to stay about 6 hours
behind the GFS model solution, and is slightly less enthused about
the strength of the system as it crosses Arkansas. Depending on
the exact timing of the front, and other features such as
available moisture and instability, some of the storms associated
with this system could be strong to severe. For now, have included
slight rain chances to start the overnight period on Friday and
have gradually increased chances through Saturday.

After the cold front leaves the state early Sunday morning, the
forecast will take on a drier and cooler pattern for several days
with temperatures gradually warming each day through the start of
the week.

A secondary embedded shortwave trough associated with the same upper
level low that brought our previous cold front, will move through
the area late in the period. Although it is too early to forecast
the specifics, this could be our next chance for rain and colder
temperatures just before Thanksgiving.

&&

.LZK Watches/Warnings/Advisories...NONE.
&&

$$


Aviation...56



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