431
FXUS64 KLZK 081800
AFDLZK

Area Forecast Discussion
National Weather Service Little Rock AR
1200 PM CST Wed Jan 8 2025

...New AVIATION...

.SHORT TERM...
(Today through Thursday Night)
Issued at 349 AM CST Wed Jan 8 2025

An upper low will be located over northwest Mexico to begin the
period. The upper low will gather strength as it moves across
northern Mexico tonight. Northwest flow over Arkansas will become
southwest late tonight.

An area of low clouds over the southeastern part of the state
will continue to move eastward early this morning. However, high
clouds will continue to stream across mainly south Arkansas. Cold
Canadian high pressure will continue to build over the southern
Plains today. The center of the surface high will be over Arkansas
tonight. High pressure and dry weather will continue over the
state through tonight with cold temperatures. High temperatures
today will be mainly in the 20s to lower 40s. Lows tonight will be
in the teens to mid 20s.

&&

.LONG TERM...
(Friday through Tuesday)
Issued at 349 AM CST Wed Jan 8 2025

Continuing to monitor model guidance trends early this mrng
regarding winter storm potential acrs the FA on Thurs-Fri. An incrsg
trend in QPF has been maintained over the past few updates, largely
due to a better consensus in the GFS/ECMWF depiction of upper lvl
features that wl drive this event. Due to incrsg confidence of the
primary snowfall accumulation footprint, portions of the Winter
Storm Watch have been upgraded to a Winter Storm Warning.

Current WV imgry depicted the initial semi-cutoff upper low over the
Baja CA, preceded by another vorticity max upstream, coming ashore
over the Pac-N/W. Through the day today, the upstream vorticity max
is progged to quickly dig S/Wrd into the Four Corners region, w/
high amplitude, troughing expected to develop over the Cntrl US. The
basal region of the ejecting trof wl be extended further S/Wwrd as
it interacts w/ the antecedent semi-cutoff upper low, resulting in a
split jet stream regime, e.g., strong Nrly flow upstream and strong
S/Wrly flow extending fm the Ern Pacific/Wrn Mexico into the Srn
Cntrl US by Thurs evng. Guidance has indicated a slower forward
translation of this trof, w/ consensus landing towards ECMWF trends,
leading to incrsg QPF values and greater PW`s w/ greater residence
time for lower to mid tropospheric moisture advection.

What does this necessarily translate to? Greater QPF wl lkly lead to
slightly higher fcst snow totals, as has been evidenced by trends in
deterministic GFS/ECMWF output, and ensemble mean guidance. However,
less efficient SLR`s due to warmer low-lvl temp profiles and bouts
of mixed-precip wl lkly still be a limiting factor for overall
accumulations.

Regarding snowfall accumulations, there are no major changes to
report w/ this fcst update. The primary footprint of greatest
accumulations (generally 5-6 inches or more) remains rooted along a
W-E axis over Cntrl AR, just south of I-40, w/ greater amounts
possible in the higher terrain regions of the Ouachita Mountains.
Local mesoscale banding appears possible as well w/in this region,
as the previous fcst update touched on. An analysis of cross-
sections through deterministic GFS/ECMWF/NAM guidance suggest some
marginal capability for CSI, though local mesoscale features such as
these are very difficult to pin down until nearly real-time analysis.
Nevertheless, the potential for some banding and locally greater
snowfall amounts/rates over the Cntrl third of the state is quite
plausible. Elsewhere in the state, a downward gradient of
accumulations is expected, w/ b/w 2-4 inches acrs N/Wrn to Nrn AR,
and far Srn AR.

Uncertainties remain over far Srn AR, where mixed-precip types wl be
more prevalent, at least thru the early portion of the event (Thurs
aftn to evng). Most point fcst soundings have continued to advertise
a borderline thermal profile near the onset of winter precip over
S/Wrn to Srn AR Thurs aftn, w/ nearly isothermal profiles (relative
to the 0C isotherm) through the "warm layer" (or at least what would
normally be considered the warm layer).

As of now, initial bouts of light freezing rain/drizzle may still be
seen thru this time frame over the AR/LA border region, and possibly
as far N as Cntrl AR, given ample isentropic ascent expected to be
ongoing. At most, a light glazing could result in hazardous road
condns prior to the onset of snow acrs the region.

Covg of winter precip is expected to incrs initially acrs S/Wrn AR
early Thurs aftn, and expand to state covg by Thurs night (lkly
after 00Z), w/ primarily snow persisting over at least the Nrn two
thirds of the FA thru the overnight PD. Srn AR wl lkly still see
mixed precip modes thru the night given warmer column temp profiles.
As the primary sfc low cont`s to move Ewrd along the Gulf Coast Fri,
covg of precip should taper off fm W to E thru the day, w/ Ern AR
possibly still seeing a light wintry mix by Fri evng.

Thru the weekend and the remainder of the long term PD, more settled
and dry condns w/ cooler (near nrml to slightly below nrml) temps
prevailing initially (possibly influenced by a residual snow pack).
By early next week, temps look to moderate upwards.

&&

.AVIATION...
(18Z TAFS)
Issued at 1155 AM CST Wed Jan 8 2025

MVFR conditions will prevail across the northern terminals
this afternoon before all sites return to VFR conditions for the
duration of the period. A sprawling upper level trough will move
into the high plains by the end of period with moisture levels
starting to increase in response. The onset of widespread precip
will occur after the period concludes but scattered flurries can
not discounted during the morning hours. Winds will gradually
shift to the southeast with time.

&&

.PRELIMINARY POINT TEMPS/POPS...
Batesville AR     32  18  35  28 /   0   0  10  90
Camden AR         42  21  38  29 /   0   0  40 100
Harrison AR       28  15  37  26 /   0   0  20  80
Hot Springs AR    38  20  35  28 /   0   0  50 100
Little Rock   AR  36  23  36  30 /   0   0  40 100
Monticello AR     41  23  39  31 /   0   0  30 100
Mount Ida AR      38  19  36  26 /   0   0  60 100
Mountain Home AR  29  15  37  27 /   0   0  10  80
Newport AR        32  20  35  29 /   0   0  10  90
Pine Bluff AR     39  21  38  30 /   0   0  30 100
Russellville AR   36  20  36  29 /   0   0  40  90
Searcy AR         34  19  36  28 /   0   0  20  90
Stuttgart AR      36  23  37  30 /   0   0  20 100

&&

.LZK WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from Thursday afternoon through Friday
afternoon for ARZ006>008-014>017-024-025-031>034-121>123-221>223.

Winter Storm Warning from noon Thursday to 6 PM CST Friday for
ARZ039-042>047-052>057-062>069-130-137-138-140-141-230-237-238-
240-241-340-341.

&&

$$

SHORT TERM...51
LONG TERM....72
AVIATION...56