Area Forecast Discussion
Issued by NWS Little Rock, AR

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FXUS64 KLZK 172048

Area Forecast Discussion
National Weather Service Little Rock AR
248 PM CST Sun Dec 17 2017

.SHORT TERM...Sunday Night through Tuesday Night

After some much needed rainfall overnight, low clouds and fog have
lingered through the afternoon hours. Therefore, the main change to
the forecast today will be the high and low temperatures. Have
decreased temperatures by quite a few degrees keeping highs mostly
below 50 degrees. Additionally, the dense cloud cover is not
expected to dissipate any time soon and will continue overnight, so
have increased overnight low temperatures a little. Expect to
stay in the mid to lower 40s.

Southwesterly flow through the mid and upper levels will help advect
moisture into the region which will increase PWAT values. Model
guidance suggests a range from .6 inches in the northern portions of
Arkansas to 1.7 inches across the south by Tuesday night. Based on
sounding climatology, the average for this time of year is around
0.5 inches, with the daily max around 1.4 inches. Therefore, with an
approaching upper level low and stalled frontal boundary across
the southern portions of the state, more than 3 and a half inches
could be seen through Wednesday in the southern portions of
Arkansas. However, the central and northern portions of the state
could see less than an inch.

Rainfall should begin Tuesday evening and continue into the long
term portion of the forecast. Thunderstorms are possible on Tuesday
afternoon and evening, with the most favored area being in the far
southern portions of the state. It appears that the strongest
thunderstorms could form after 00z Wednesday when CAPE and shear
values increase as the aforementioned vort max approaches the
area, so stay tuned for updates.


.LONG TERM...Tuesday Night through Saturday

All attention of late has been
on the potential for winter weather as the Christmas holiday
weekend gets started. I`ll certainly get to that, but first let me
discuss the Tuesday night time frame as it deserves to be

In general the long term period will continue to be a warm one, with
above normal temperatures. Current shortwave trough energy south of
Arizona will eventually eject eastward towards Arkansas as a compact
cutoff low, moving across the state right at the beginning of the
long term period. There are two aspects of this system to discuss,
and those are flash flooding and the possibility of some severe
storms in the southeast. Let`s address the flash flooding aspect.
This system will draw Gulf moisture northward into northern
Louisiana and southern Arkansas on Tuesday. Forecast PWAT values
from numerical guidance show top 10 values (roughly 1.60") for the
North Little Rock sounding location, and around 1.80" in the
southeast part of the state Tue afternoon/evening. With that kind of
moisture in play, and decent convection forecast, it is possible
that heavy rains could produce some localized flash flooding. The
system overall will be quick moving so I don`t expect widespread
problems there. The other aspect of this is the possibility of
severe storms. Again, the focus will be in the south and southeast.
This is a marginal case as the timing will be late Tue evening and
into the overnight hours. However forecast soundings indicate some
modest surface instability Tue evening, with wind shear supportive
of organized convection and a marginal damaging wind threat.

After the Tue night low passes, the region will remain beneath zonal
upper flow while a strong upper trough dives from the Pac NW
towards the Four Corners region on Wed and into Thu. Surface winds
will remain out of the south so warmer than normal temperatures are
expected to continue. Strong surface low pressure develops in the
plains in response to this incoming trough Thursday night into
Friday, with the associated cold front moving into Arkansas by late
Friday afternoon. Over the last 24 hours there has been much better
consensus on this type of evolution of the upper pattern late in the
week. Regarding the chances of winter weather, this type of pattern
would favor another widespread rainfall event across Arkansas on
Friday ahead of the front, with the possibility of rain changing to
a rain/sleet/snow mix on the backside of the precipitation shield as
cold air rushes in before it comes to an end. I would stress at
this point that It`s still early and things can change, so I would
advise you to closely monitor forecasts for the upcoming Christmas


Batesville AR     42  60  48  64 /   0   0  20  40
Camden AR         43  63  53  69 /  10  10  50  80
Harrison AR       41  59  46  63 /  10   0  10  20
Hot Springs AR    43  62  50  66 /   0  10  30  70
Little Rock   AR  43  62  50  66 /   0   0  30  70
Monticello AR     44  62  53  68 /  10  10  50  80
Mount Ida AR      41  62  50  68 /   0  10  30  70
Mountain Home AR  42  59  45  63 /  10   0  10  20
Newport AR        42  59  47  64 /   0   0  20  40
Pine Bluff AR     43  61  51  66 /  10   0  40  70
Russellville AR   42  61  47  64 /   0   0  20  60
Searcy AR         42  61  48  64 /   0   0  20  50
Stuttgart AR      43  61  50  66 /   0   0  30  70

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


Short Term...CROSS / Long Term...64 is the U.S. government's official web portal to all federal, state and local government web resources and services.