881
FXUS64 KLZK 302347
AFDLZK

Area Forecast Discussion
National Weather Service Little Rock AR
647 PM CDT Sun Jun 30 2024

...New SHORT TERM, LONG TERM, AVIATION...

.SHORT TERM...
(Tonight through Tuesday)
Issued at 629 PM CDT Sun Jun 30 2024

Widespread convection Sunday afternoon and early this evening
along with abundant cloud cover has resulted in heat index values
that are well blow criteria for any type of heat related
headlines. As such, the excessive heat warnings and heat
advisories have been cancelled early.

Latest surface analysis places a slow moving cold front somewhere
over central Arkansas. This boundary will reach the Arkansas and
Louisiana border early Monday morning. Slightly cooler but much
drier air will continue to filter into the forecast area which
will reduce the heat stress related conditions for at least a day
or so, even through temperatures themselves will be very close to
seasonal averages.

&&

.LONG TERM...
(Tuesday Night through next Sunday)
Issued at 226 PM CDT Sun Jun 30 2024

In general west-northwest flow aloft will be in place over the
central CONtinental United States (CONUS) from Saturday night
through Wednesday. In the absence of a powerful upper level trough
or ridge, shortwave troughs will generally provide the perturbations
that cause the geostrophic flow aloft to alternate between pure
westerly and shifts to northwesterly flow aloft. These shifts are
important because they will have a cascading impact on surface
weather conditions east of the Rockies to the Mississippi River.
When the flow aloft is oriented westerly, as the westerly flow
moves from the high terrain of the Rockies to the lower terrain of
the plains, the atmospheric column expanding in depth will cause
a surface trough to develop over the higher plains east of the
Rockies. This is due to the conservation of potential vorticity
which effectively creates surface troughing due to the atmosphere
moving from a compressed to expanded vertical state simply due to
elevation change alone.

With westerly flow aloft causing cyclogenesis over the high plains,
periods of northwest flow aloft will drive weak/Pacific type cold
frontal boundaries southeast, providing synoptic scale lift east of
the surface cyclones or troughs that develop during conditions of
westerly flow aloft. The western troughs will cause south or
southeasterly low-level flow to set up over Arkansas pumping
moisture rich Gulf of Mexico air north across the state. Because
this period exists in early June, the sun angle is just about as
high as it gets over the CONUS leading to extremely efficient
heating each day. The positive moisture flux combined with the
efficient daytime heating will be consistent drivers of
thunderstorm energy across the state Sunday through Wednesday.
Everytime one of the pacific type cold fronts interacts with this
energetic airmass, it will kick off a line of thunderstorms that
will continue downstream into the axis of hot and humid air. As a
result, this type of pattern is well known to send multiple linear
mesoscale convective systems (MCSs) across the central CONUS this
time of year. Each linear MCS will bring with it a threat for
damaging winds and at least a marginal threat for hail and quick
spin up tornadoes. Localized flooding is also possible, but
widespread flooding is not common because these types of storm
systems tend to move and don`t sit in one place all that long.

This cycle of linear MCS, reset the atmosphere with southerly winds,
just in time to allow another linear MCS roll through will continue
throughout the extended forecast period will continue through Monday
when a stronger upper trough digs southeast over the western Great
Lakes region driving a Pacific type cold front well south of
Arkansas interrupting the moisture reloading cycle of this weekend
through early next week. After Wednesday drier air will move across
the state leading to a period of drier weather beginning Thursday
and likely continuing into next weekend.

&&

.AVIATION...
(00Z TAFS)
Issued at 629 PM CDT Sun Jun 30 2024

Convection associated with a slow moving cold front continues to
slowly wane with the loss of daytime heating but a few showers and
thunderstorms will remain possible over the central and southern
TAFS through mid evening. VFR conditions will continue with winds
generally light and variable through the period.

&&

.PRELIMINARY POINT TEMPS/POPS...
Batesville AR     67  85  64  93 /  10   0   0   0
Camden AR         75  92  68  98 /  20  10   0   0
Harrison AR       67  87  65  95 /  10  10   0   0
Hot Springs AR    73  90  69  97 /  30  10   0   0
Little Rock   AR  75  89  69  95 /  20   0   0   0
Monticello AR     77  91  69  96 /  20   0   0   0
Mount Ida AR      73  89  68  95 /  20  10   0   0
Mountain Home AR  67  84  64  93 /  10  10   0   0
Newport AR        68  85  64  92 /   0   0   0   0
Pine Bluff AR     74  89  67  95 /  20   0   0   0
Russellville AR   73  89  68  95 /  20  10   0   0
Searcy AR         70  87  64  93 /  20   0   0   0
Stuttgart AR      74  87  67  93 /  20   0   0   0

&&

.LZK WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

SHORT TERM...56
LONG TERM....67
AVIATION...56