FXUS64 KLZK 200008
Area Forecast Discussion
National Weather Service Little Rock AR
708 PM CDT Sun May 19 2019
.AVIATION...20/00Z TAF CYCLE
Sctd convection wl linger early this evening ovr far SE AR, with
VCTS included at KLLQ, ahead of a weak bndry. Otherwise, VFR conds
wl prevail thru much of tngt. The bndry wl eventually lift back to
the N on Mon, with MVFR CIGS forming along it ovr S AR Mon mrng.
Low end VFR CIGS can be expected ovr much of the FA Mon aftn, with
VCTS mentioned at most sites. /44/
.PREV DISCUSSION...(ISSUED 305 PM CDT Sun May 19 2019)
SHORT TERM...Tonight Through Tuesday
19z objective surface analysis indicates a weak cold front
across northwest sections of of the forecast area. This feature
is expected to move to southern sections overnight before
stalling. Mesoscale analysis indicate moderately unstable
conditions have formed ahead of the boundary. Forcing along the
boundary appears to be weak, and any development through late
afternoon should be limited.
Southerly low level flow will develop and deepen on Monday, in
response to approaching upper level energy from the southwest and
west. Lift may be sufficient for widely scattered convection late
Monday and Monday night across western sections.
Numerical guidance continues to advertise the potential for a
strong convective event for Tuesday. Linear MCS development is
likely, which would be moving into western sections of the state
by early afternoon. Forecast soundings suggest damaging wind gusts
would be the primary threat with this event.
LONG TERM...Tuesday Night Through Sunday
The period opens with a sharp shortwave trough and associated
modified surface cold front dragging eastward across AR. Dynamics
and associated instability (CAPE values 2,800+ ahead of the
system) will lead to widespread showers and thunderstorms as the
system progresses eastward across the state. Precipitable water
values connected with the system approach two inches so brief
flash flooding is but one of the severe weather modes expected for
this event. Fortunately, the system will begin to weaken somewhat
with the loss of daytime heating as it moves into central and
eastern AR Tuesday evening so the system may not have enough time
to bring widespread flooding to the region. Damaging wind gusts
and perhaps an isolated tornado will also be possible Tuesday
night in the strongest storms.
For Wednesday, some showers and isolated thunderstorms will still be
possible in the moist airmass that will be in place across the
region. However, the forecast area will start to come under the
influence of strong high pressure building aloft from the southeast
US and this will work against precipitation development. Highs
Wednesday afternoon will be somewhat above normal and generally
range from the mid to upper 80s area-wide.
For Thursday through Sunday, generally precipitation-free but humid
conditions are expected as the upper high over the southeast US
strengthens and expands westward across the northern Gulf of Mexico.
Temperatures across AR will remain above normal through this four
day period as weak south to southwest surface flow persists. Highs
will generally range from the lower 80s over the higher terrain of
northern AR to near 90 over the south.
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