LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1234 AM CDT Sat Oct 15 2022
Valid 151200Z - 161200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SOUTHWEST OKLAHOMA
TO EASTERN ARKANSAS...
...SUMMARY...
Afternoon and evening thunderstorms are expected to evolve from
Oklahoma to the Tennessee Valley area. Isolated large hail and
strong gusts will accompany these thunderstorms. Additional strong
storms may produce sporadic hail and gusty winds across portions of
southeast California central and southern Arizona.
...Synopsis...
Early-morning surface observations across the southern Plains reveal
a cold front beginning to stall across southern KS and northern OK.
This boundary will meander southward into central OK/AR through the
day and will be the impetus for thunderstorm development later this
afternoon and tonight. Across the Southwest, an upper low noted off
the coast of southern CA in water-vapor imagery will drift east
through the day and support widespread shower and thunderstorm
development across southern CA and southern AZ.
...Southern Plains...
The stalling cold front across OK/AR is expected to undergo
frontolysis through the day amid ample daytime heating across the
region. Diurnal boundary-layer mixing coupled with a modest increase
in low-level moisture (dewpoints climbing into the 50s and low 60s)
should result in 1000-2000 J/kg MLCAPE with minimal inhibition
across eastern OK into central AR by late afternoon. Initial
thunderstorm development is probable along the I-40 corridor where
low-level confluence along the boundary will likely be maximized and
inhibition should be weakest. Initially discrete cells will pose a
severe hail/wind threat before storm motions along the boundary
foster gradual upscale growth and an increasing wind threat into the
evening hours for eastern OK/AR.
Further west into central/western OK, stronger inhibition should
limit convective development until after 00 UTC when lift along the
remnant frontal zone increases due to 1) a strengthening low-level
nocturnal jet and 2) ascent associated with the approach of an
embedded mid-level perturbation (noted in water-vapor imagery over
northern MT). Rapid upscale growth is anticipated given mean flow
along the boundary, which will predominantly favor a wind threat
through the overnight hours, through severe hail is possible with
the initial development.
...Southern High Plains...
Isolated to scattered convection is expected to move out of
Chihuahua, Mexico and into the southern High Plains by the late
afternoon/evening hours. This activity will migrate into a
deeply-mixed air mass conducive for strong to severe downburst
winds. While there is some uncertainty regarding the timing of
convection with peak daytime heating/mixing, most guidance suggests
a reasonable potential for isolated strong/severe gusts to warrant
probabilities.
...Lower Colorado River Valley into southern Arizona...
Broad ascent evident in satellite imagery across northern Mexico and
southern AZ/NM should remain over the Southwest over the next 24
hours as the upper low drifts to the east. While the 00 UTC TUS
sounding sampled very dry boundary-layer conditions, GOES PWAT
imagery suggests a reservoir of higher quality low-level moisture is
in place through the lower CO river valley and southern AZ where
dewpoints are in the 50s. This moisture, coupled with steepening
mid-level lapse rates, should support 1000-1500 J/kg MLCAPE by late
afternoon. Shower and thunderstorm activity will likely gradually
increase through the day in tandem with increasing buoyancy. Strong
upper-level flow associated with the wave should support some
hodograph elongation and the potential for a few organized cells
capable of severe hail/wind.
..Moore/Broyles.. 10/15/2022
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