Area Forecast Discussion
Issued by NWS Little Rock, AR

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FXUS64 KLZK 280530 AAA
AFDLZK

Area Forecast Discussion...Update
National Weather Service Little Rock AR
1230 AM CDT SUN AUG 28 2016

.AVIATION...

VFR conditions will prevail through much of the period. Patchy areas
of fog are expect to form later tonight and into Sunday morning.
Some visibilities will be reduced to MVFR and isolated IFR. Winds
will be light and variable or east at less than 5 mph overnight.
Convection will be more isolated on Sunday. Winds on Sunday will
be northeast to southeast at 5 to 10 mph. (59)

&&

.PREV DISCUSSION...(ISSUED 243 PM CDT SAT AUG 27 2016)

SHORT TERM...Today Through Monday

Regional radar imagery showed scattered showers and thunderstorms
draped along a line from Mountain Home to Mena with some spotty/
isolated showers and thunderstorms found elsewhere across the
state. The band of scattered shower and thunderstorms is the most
likely to persist this afternoon through sunset...so kept the
highest POPs across northwest Arkansas aligned with this band
through early this evening. Without any obvious large scale
forcing mechanism supplying lift for this activity...think that
most of it will dissipate shortly after sunset.

Afternoon water vapor satellite imagery showed that the large
scale flow pattern over the region was dominated by upper level
ridging centered over the southeast United States. On the
periphery of this upper ridge...there were a couple of mid-level
cyclonic disturbances that the National Hurricane Center
continues to watch for potential upscale growth into an organized
tropical low-pressure system. Deterministic model guidance
continues to indicate that this is a low...but non-zero
probability in the week ahead. The closest disturbance to Arkansas
was located just over the Gulf of Mexico near the Texas and
Louisiana coasts. This system has not strengthened any of the past
24 hours...so it appears unlikely to become a direct threat to
Arkansas. It could potentially move north off the Gulf coast and
bring some deep tropical moisture over the state next week...but
even this seems unlikely based on the consensus of 12z model
guidance.

In the short term...the GFS/NAM/ECMWF all indicate that the upper
level ridge over the southeastern CONUS will extend west and bring
weak ridging aloft over Arkansas through Monday afternoon. This
ridging appears to be very weak in nature and is not expected to
send significant forcing for subsidence over the state. It`s main
influence will be to divert the weak disturbance off the TX/LA
coasts to the west towards Texas and away from Arkansas. With this
in mind...have a very similar forecast for Sunday and Monday.
Highs are expected to be slightly above normal...topping out in
the lower 90s for most locations while low-level humidity remains
high. Afternoon heat index values should top out in the 100-105
degree range each day. Due to weak ridging aloft...thunderstorms
will still be possible each afternoon...but the coverage should
trend towards isolated versus scattered. No significant severe
thunderstorm threat or flooding threat is expected due to the
limited coverage and duration of convection through Monday
afternoon.

Cavanaugh

LONG TERM...Monday Night Through Saturday

Weak upper ridge will weaken some Tuesday and allow a weak cold front
to sag into the state and likely to become stationary. The front will
be difficult to analyze due to the surface wind flow also associated
with and area of low pressure across southern LA. This front will
have only minimal impacts on temperatures, but it may increase the
chance for mainly afternoon showers or thunderstorms Tue and Wed.
With the light NE surface flow, slightly drier air may work into the
northeast half of the state. The front is likely to sag further
south on Thu resulting in lessening chances for showers with the best
chances of showers likely confined to western third of AR Thu and
Fri. A slight chance of showers or storm returns statewide on Sat as
with the upper ridge redeveloping well east of us again and
continued low pressure along the Texas and LA coasts.

Worth watching is what happens to Tropical system 99L. ECMWF is
bringing this into the Gulf of Mexico and indicates a rapidly
strengthening tropical system into the Mobile, AL vicinity by Friday
afternoon, while the GFS suggests a much weaker system hanging out
near the TX/LA coastal border.
&&

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

$$



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