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fxus64 klzk 211158 

Area forecast discussion
National Weather Service Little Rock Arkansas
558 am CST Thu Nov 21 2019

Aviation...21/12z taf cycle

A band of rain showers is currently moving through cntrl/ern AR, with
scattered rain showers and possibly isolated thunderstorms and rain expected this
afternoon, but have kept thunder limited to thunderstorms in the vicinity. Widespread MVFR
ceilings and visible are being seen at most terminals. MVFR ceilings are
expected to prevail through most of thurs afternoon before
deteriorating to IFR ceilings from nrn to cntrl terminals thurs
evening. Additionally, have added ws group for all terminal sites
through late thurs morning.


Previous discussion...(issued 412 am CST Thu Nov 21 2019)
short through Friday night

Current WV satellite imagery is painting a dynamic upper-level
pattern over the Continental U.S. This morning. A large vorticity maxima
embedded within a potent trough is currently positioned over the
swrn US. Broad ridging is shifting ewrd over the Midwest/nern US,
with a small shortwave embedded upstream of the ridging over the
nrn plains. This upper-level perturbation is contributing to upper
mass divergence and driving a strong sfc cyclone centered in IA,
with a tailing cold front moving through northwest MO/ern Kansas and extending
swrd into OK. Locally, a band of rain showers is currently moving
ewrd through the state, with scattered showers expected to continue
through the day.

Thurs...the aforementioned sfc cyclone will quickly lift north into
the Great Lakes region through thurs afternoon. The natural state
will remain within the warm sector of this cyclone through most of
the day, with modest srly sfc flow and warm air advection contributing to
isentropic ascent. Strong srly flow has contributed to an
unseasonably moist airmass over the fcst area, with anomalous and
even some record pwats between 1-1.5". Modest ascent and anomalous
moisture will allow for scattered showers across the state thurs.
Temperatures over the region will not vary greatly, with highs
around the upper-60s and even some 70s in the south. The tailing
cold front will slowly sag swrd through the afternoon, entering
the state from the northwest thurs evening. As this front encounters the
moist airmass in place, a second round of precipitation and maybe
even a few rumbles of thunder is expected over the nrn portions of
the state. Rainfall totals thurs will range from 1-2" over nrn
AR, with isolated larger amounts possible.

Fri...the cold front will slowly move swrd through the state Fri,
with sufficient low-level moisture and enhanced sfc convergence
along the boundary remaining the Focal Point for rain showers and a
few isolated thunderstorms. Rain chances will slowly taper off
through Fri from west to east as the front clears the state, with
cooler/drier air filtering in behind. Temps Fri afternoon will be
cooler than the day prior due to the fropa. Over cntrl/srn AR, highs
will be in the mid-50s to upper-60s ahead of the front, while to the
north of the boundary, upper-40s can be expected. Fri night into Sat
morning, lows will flirt with the freezing mark in north/nwrn Arkansas with
lower-40s for the remainder of the state.

Long term...Saturday through Wednesday

The period will initiate with the h500 shortwave trough making
eastward progress across the mid Mississippi Valley and the surface
cold front continuing to move well east of the area. The flow aloft
will remain northwesterly with surface ridging holding in place,
providing for cool and dry conditions.

Temperatures begin to moderate for the first couple of days of the
new work week as the flow aloft becomes more westerly and surface
ridging shifts east of the area providing swrly flow. In the zonal
flow aloft, a new h500 shortwave trough will approach from the Great
Basin on its way toward the Central Plains. At the surface, an area
of low pressure will develop to the west of the state with a cold
front trailing to its southwest.

Ahead of these features, some rain is expected to develop by mid-
week. There is still some disagreement regarding strength and timing
of the upper trough amongst model solutions, but the output is much
more consistent than what was observed 24 hours ago.


Lzk watches/warnings/advisories...none.

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