Area Forecast Discussion
Issued by NWS Little Rock, AR

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FXUS64 KLZK 262317 AAA

Area Forecast Discussion...UPDATED
National Weather Service Little Rock AR
617 PM CDT Tue Oct 26 2021

Updated for 00Z terminals...

Gradually, clouds will increase over the next 24 hours, as system
over the Southern Plains shifts toward the region. By the end of
the period, SHRA/-RA will be prevalent with ceilings in most areas
becoming mvfr or lower (especially over the north and west).

.PREV DISCUSSION...(ISSUED 306 PM CDT Tue Oct 26 2021)
SHORT TERM...Tonight Through Thursday

Metsat imagery this afternoon is showing low and mid level cloud
cover spreading across the state, with upper level cloud cover
expanding across the south and west. Over the next few days, we`ll
be watching an upper SWT, currently over the SW desert region, and a
surface low, moving from the Rockies towards the ESE.

Models are in agreement with the upper SWT deepening to a closed
upper low as it digs into the south-central U.S. moving into the mid-
week period, providing widespread forcing for ascent across the
region. At the same time, the surface low will track ESE, moving
into OK by Wed morning and moving across AR Thurs, creating low-
level convergence across the state.

These features will be moving into a moisture-rich environment.
Ensemble and deterministic guidance forecasts PWAT values above the
climatological 90th percentile value of 1.36 inch, with between 1.5-
2+ inches across the southern parts of the state. At this time,
forecasting one to two inches potential rainfall with this
system. Locally higher amounts are possible in stronger storms.

Severe Potential...

Forecast CAPE looks unimpressive, but using the Theta-E difference
between the surface and the top of the omega layer indicates
potential for convection/buoyancy. We also have the 500mb low
upstream, providing widespread forcing for ascent across the region.
The cold core of the low looks to be placed over Wern OK at the time
of possible QLCS moving across the state. During this time, upper
level flow looks to be out of the SW, so the buoyant layer looks to
be low enough in the atmosphere that lightning potential appears
low. Forecast sounding are also showing 0-1km SRH 200-400+ m2/s2,
indicating potential for low-topped supercells in the inflow notches
of the QLCS. Greatest potential for severe storms appears to be
across the southern portions of the state, with damaging winds and a
few tornadoes being the most likely storm modes. The severe
potential portion of the forecast is conditional on the basis that a
secondary line of convection develops behind the main area of
precipitation Wed afternoon/evening.

LONG TERM...Thursday Night Through Tuesday

At the beginning of the period on Thursday night into the day on
Friday, the surface low pressure will be centralized over the
Missouri Bootheel and chances of rain will be confined mainly to
portions of northern Arkansas.

FRIDAY: The position of the surface low will continue eastward away
from the CWA into middle portions of Tennessee; however, behind in
its wake, will be a strong pressure gradient with brisk
northwesterly winds that will bring colder and drier air into the
region. Rain chances begin to drastically taper off and become non-
existent by end of day on Friday for the CWA. High temperatures on
Friday will be confined to the mid 50`s across the northern portion
of the state, lower 60`s across the middle and southern sections of
the state.

SATURDAY: An airmass of much colder air is ushered into the region
by strong northwesterly winds behind the surface low/cold front that
is now positioned over the mid-Atlantic CONUS region. Low
temperatures Saturday morning will be in the lower 40`s across the
northern portion of Arkansas while reaching into the middle and
upper 40`s elsewhere statewide. Winds will begin to lighten as the
surface pressure gradient weakens and clouds will begin to exit the
region throughout the day. High temperatures will remain into the
low 60`s across the northern part of the state while delving into
the middle to upper 60`s from the I-40 corridor in central Arkansas
and locations southward. A few locations may even reach 70 degrees.

SUNDAY: Low temperatures on Sunday morning begin in the low to mid
40`s statewide. During the day, the 500mb ridge begins to intensify
over the Natural State. The ridge will allow high temperatures
through the day to peak into the middle 60`s across northern
Arkansas and low to mid 70`s will be present southward as you
traverse the state. No need to be afraid, Halloween weekend overall
looks chilly, but dry across the Natural State.

MONDAY/TUESDAY: Into the next workweek, Monday trends to be much
like the conditions we see over the weekend however, big changes
once again are knocking on the door as our next cold front
approaches the CWA by Tuesday. Details on specifics will still need
to be ironed out as we remain seven days out, but latest model
guidance do agree on a FROPA occurring during the day on Tuesday
with accompanying chances for rain along this boundary.


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


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