Area Forecast Discussion
Issued by NWS Little Rock, AR

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893
FXUS64 KLZK 212341 AAA
AFDLZK

Area Forecast Discussion...UPDATED
National Weather Service Little Rock AR
641 PM CDT Fri Apr 21 2017

.AVIATION...
Warm/quasi-stationary front will meander around over the next few
hours before the cold front and associated surface low move
across. Initially, there will be showers/isolated storms, but
these should become more widespread as the system moves into the
state. These will continue into the morning Saturday. Lowest
conditions will be in the northern sites, with prevailing IFR
through the period, as the surface system moves through, and upper
low swings across tomorrow. Over the remainder of the area,
expect gradual deterioration this evening. Winds will be erratic
in the vicinity of the stalled front, then gradually shift to the
west and northwest behind the cold front. Precip will diminish
during the day Saturday. Tafs already out.
&&

.PREV DISCUSSION...(ISSUED 239 PM CDT Fri Apr 21 2017)

DISCUSSION...

Main concerns in this forecast cycle are chances of convection and
any risk of severe storms in the first 24 hours. Dry and cooler
weather after the cold front pushes through the state for Saturday
night, Sunday and into Monday. Then a warming trend with some
chance of rain back in the forecast. Severe thunderstorm watch is
in effect until 3 pm for parts of west-central AR.

The area of showers and thunderstorms this morning moved off to
the northeast, while the line of storms currently moving across
the northern half of the state continues to have heavy rain, gusty
winds and possible small hail. This line has be showing signs of
weakening as it moves northeast.

The convection was associated with the frontal boundary and an
upper level shortwave as it moves over the area. The front was
near the Little Rock area, with temperatures in the 60s north of
it, while the 70s to lower 80s to the south. We have seen a few
strong to severe storms, with strong winds being reported in
spots. This area of storms will continue to move northeast and
weaken this evening.

SHORT TERM...Tonight Through Sunday Night

Will keep a good to likely chance of showers and thunderstorms
over AR this evening and tonight, until the cold front and upper
system move through the region. Some risk of isolated strong to
severe storms will continue this afternoon, evening and early
into the overnight, mainly over central to southern areas. Some
rain chances will be possible on Saturday from wrap around from
the upper and surface low pressure, and forecast will show this.
Temperatures will cool behind the cold front back to below normal
temperatures, especially in the north to central, with lows in the
50s to upper 40s, while highs in the 60s to 70s. Dry for Sunday
with mild temperatures. A warming trend into next week.

LONG TERM...Sunday Night through Friday

Sunday Night through Tuesday Night...Cooler and drier air will
remain in place across Arkansas Sunday night into Monday morning.
Upper level ridging will keep mostly clear skies in place and will
keep rain chances near zero. Light and variable winds for much of
the day on Monday are expected to become southerly Monday night as
surface low pressure deepens on the lee side of the Rockies. Tuesday
will remain dry as southerly winds bring humidity back across the
state. Temperatures are expected to remain in the 70s on Monday but
will climb back towards 80 on Tuesday as southerly winds work to
bring heat and humidity back across the state.

Wednesday through Friday...Models indicate that a strong upper level
storm system will bring a chance of thunderstorms across Arkansas
mid to late week...however the details on the timing and strength of
this system have been varying quite a bit from model to model. The
12Z GFS and 00Z ECMWF would indicate that a line of thunderstorms
will move across Arkansas Thursday afternoon and evening...so have
30 POPs in the forecast at this time. There is a chance of
thunderstorms before this system arrives in general weak lift and
warm air advection on Wednesday...but only went with a 20 POP to
cover this activity for now.

Complicating matters...model guidance is consistently advertising a
second and stronger upper level storm system moving into the Plains
this weekend which will keep some warm air advection and weak lift
in play from late this week through next weekend. With some doubt in
the placement and strength of synoptic scale features just have low
POPs sprinkled out through the remainder of the forecast at this
time.

Wherever storms develop across Arkansas with the first storm
system...some severe weather appears likely...but confidence
regarding the details on the timing and strength of these storms is
currently low. From Thursday through next weekend...the weather
pattern certainly appears to be more active with a couple of rounds
of severe weather and heavy rainfall possible.
&&

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

$$


Aviation...57



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