Area Forecast Discussion
Issued by NWS Little Rock, AR
FXUS64 KLZK 260536 AAC
Area Forecast Discussion...UPDATED
National Weather Service Little Rock AR
1236 AM CDT FRI AUG 26 2016
Updated for the 06z aviation discussion below.
Upper level high pressure continues over Tennessee. A short wave on
the west side of this high continues to bring showers and isolated
thunderstorms to Arkansas, mainly central and south. Additional
showers will move through central and south sections for the next 2-
3 hours. Rest of the night should be dry, but another short wave
rotates around the high Friday for more showers and thunderstorms.
VFR and MVFR conditions are expected.
.PREV DISCUSSION...(ISSUED 736 PM CDT THU AUG 25 2016)
Showers and isolated thunderstorms continue across the central and
south. Additional showers and thunderstorms are moving into the
area from the south. Expect the precipitation to diminish before
midnight. Adjusted pops, cloud cover, and rainfall amounts to
reflect this continuing rainfall.
PREV DISCUSSION...(ISSUED 315 PM CDT THU AUG 25 2016)
SHORT TERM...Tonight Through Saturday
As expected...SCTD convection noted acrs the FA this aftn. The
activity was occurring on the WRN periphery of an upr high that was
centered ovr TN...with a plume of tropical moisture /PW values in
excess of 2 inches/ conts to advect into the region. Do expect the
bulk of this activity to diminish shortly aft sunset this evening.
Opted to keep small rain chcs in the fcst later tngt as a weak
impulse is fcst to lift NWD thru the area.
Not much chg noted with the overall pattern heading into the
weekend. High pres aloft wl rmn centered well E of AR. The resulting
upr flow wl keep plenty of tropical moisture in place ovr the FA.
Sctd convection wl rmn the fcst Fri and Sat...mainly diurnal in
nature. Meanwhile...a fntl bndry wl attempt to apch NWRN AR Fri into
Sat...but wl encounter SWLY flow aloft...which may inhibit it fm
making into the FA.
High temps the next few days wl range fm the mid 80s to lower 90s...
thanks to contd rain chcs/cloud cover. Aftn heat index values are
fcst to rmn blw critical lvls each day...so not headlines planned.
LONG TERM...Saturday Night Through Thursday
The extended weather pattern is contingent upon a couple of
important factors. The first is the quasi-stationary front that is
expected to push into northwestern Arkansas before Saturday night.
By Sunday...all 12z model guidance indicates that this boundary will
dissipate or wash out leaving no discernible low-level convergence
or baroclinic signature to speak of. This is contingent upon
thunderstorm activity along the front Friday and Saturday though.
Numerous thunderstorms along and northwest of the front could
reinforce the baroclinicity of the front and cause it to remain in
place on Sunday. Seeing as no models support this solution at this
time...only kept pops in the 20 to 30 percent range.
Assuming the front has dissipated by Sunday...the forecast for
Sunday through Thursday will be very similar. Weak upper level
ridging will prevent any organized weather systems from impacting
Arkansas. We will remain fairly warm and humid from Sunday through
next week...so isolated to scattered thunderstorms can be expected
during the peak heating hours of the day each day with a dry
forecast likely after sunset and through the morning hours of the
day each day. Highs will generally be near or slightly above normal
due to weak high pressure aloft.
The second important contingency to the forecast is keeping a close
eye on any organized tropical system that may develop in the warm
waters of the Gulf of Mexico. The consensus of the 12z model
guidance indicates that any tropical system will remain well east of
Arkansas...however previous model runs indicated that a decaying
tropical system could move over the state next week. This forecast
does not account for any decaying tropical system at all...so if
that looks more likely in later forecasts...significant changes to
the forecast will be necessary in the future. The primary concern in
this unlikely outcome would be heavy rain and the associated
potential for flooding. This is something we will certainly be
keeping an eye on in future forecasts...but the probability is so
low as this time it is unlikely that any decaying tropical system
will impact Arkansas for the next 7 days.