Area Forecast Discussion
Issued by NWS Little Rock, AR

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FXUS64 KLZK 111134 AAA
AFDLZK

Area Forecast Discussion...UPDATED
National Weather Service Little Rock AR
634 AM CDT Tue May 11 2021

.UPDATE...

Updated to include the 12Z aviation discussion.

&&

.AVIATION...

TSRA will expand across the area today and affect all sites,
although confidence is highest at central/southern terminals in
the 11/18Z-12/02Z time frame. Activity will diminish after around
12/00Z, but cigs will lower through the evening with MVFR to IFR
restrictions expected overnight. Winds remain E to NE and will
increase late in the period with speeds up to 15 kts.

&&

.PREV DISCUSSION...(ISSUED 417 AM CDT Tue May 11 2021)

SHORT TERM...Today Through Wednesday Night

The most persistent convective activity this morning has been
confined to far southern AR and adjacent areas in LA/TX/OK/MS,
coincident with a pool of enhanced low-level moisture and warm air
advection. Mosaic radar does show additional isolated showers
over much of the rest of AR, generally along and south of a 850 mb
front analyzed from near FSM eastward to near MEM. Will see this
trend continue through the morning with the highest coverage of
rain initially over the south/west and more isolated activity
elsewhere.

As a large-scale mid/upper trough moves into the Plains today and
another low-amplitude wave moves across TX, broad forcing for
ascent will increase and the low-level mass field response will
advect rich moisture over the area. Rain and thunder coverage will
increase as a result with most of the area seeing rain today.
Modest instability (MLCAPE on the order of 1000-2000 J/kg) will be
most favored across southern AR and perhaps into central sections,
so kept highest thunder probabilities over those locations. We
still have moderately steep lapse rates in place aloft, so
wouldn`t be surprised to see hail again in storms today, although
the overall severe threat is low.

Temperature-wise... abundant cloud cover and rainfall will limit
high temperatures today and did undercut initialized guidance,
especially over western AR. Readings will range from the mid/upper
50s over the western half of the state with low 60s elsewhere.
Lows tonight will fall into the 40s and 50s again (no
complaints... we will be hurting for this once summer really kicks
in...).

The heaviest rain and overall highest QPF is anticipated along
and south of the aforementioned 850 mb front, which is progged to
wobble over northern/central AR through the period. While we are
not anticipating the magnitude of rain that folks south of us will
see over the next few days, central AR could pick up on the order
of 0.5 to 1 inch, give or take, with 1 to 2 inches or more over
southern AR. Isolated higher totals are be possible with these
more driven by heavy convective rain in an environment
characterized by PWAT values of 1.5+ inches. Isolated flash
flooding will be possible with the highest relative threat over
southern sections.

Tonight through Wednesday night, the Plains trough will continue
pushing east with deep tropospheric moisture gradually waning.
Increasing static stability and subtle subsidence in the wake of a
passing mid- level wave tonight should knock back precipitation
coverage with rain and thunder lingering over southern AR. By
Wednesday and Wednesday night, rain should be south of the state.
While temperatures will moderate some by Wednesday afternoon,
values will remain below average.

LONG TERM...Thursday Through Monday Night

A large area of high pressure will build over the region from the
north Thursday and Friday. Under the high, it will be dry with
below average temperatures.

By the weekend, the high will slide to the east, and return
flow will bring progressively warmer temperatures and increasing
moisture. As this happens, a storm system over the Rockies
will slowly head toward the Plains, with an even larger system to
follow from the Pacific Northwest. Ahead of the systems, strong
riding will occur from the Great Lakes to Florida. This will
slow the systems down.

As the systems slowly approach, have isolated scattered showers
and a few thunderstorms in the forecast Saturday and Sunday.
Precipitation will be mostly confined to northern/western sections
of the state. Chances of rain will go up in much of the state
on Monday.

Given the pattern, this looks like mainly a heavy rain event
without much in the way of severe weather. Much of the event
will unfold after the end of the period, and will know more
what will happen as additional data is received.

&&

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

$$


Aviation...DTC


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