SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1242 AM CDT Fri Sep 16 2022
Valid 161200Z - 171200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL
PLAINS...
...SUMMARY...
Severe thunderstorms are possible across portions of the central
Plains on Friday.
...Central Plains...
Latest water-vapor imagery depicts a well-defined mid-level
short-wave trough over NV, advancing east in line with latest model
guidance. 500mb speed max is forecast to translate across southern
NV into western CO by 18z, then into NE during the late evening.
This feature should encourage a weak surface lee low to back into
northeast CO by peak heating, then to be dislodged into NE/northern
KS where weakening is expected by 17/12z.
Strong boundary-layer heating will once again be noted along the lee
trough from west TX into southwestern NE and southeast WY. Forecast
soundings suggest convective temperatures may be breached by 21-22z,
and large-scale support ahead of the aforementioned short wave
appears favorably timed for scattered robust convection. NAM 22z
sounding for OGA exhibits surface-6km bulk shear in excess of 40kt
with steep surface-3km lapse rates. It appears supercells will
evolve by late afternoon across the central High Plains where SBCAPE
will likely be on the order of 1000-1500 J/kg. While initial
activity should evolve near the lee trough, a synoptic front draped
along the SD/NE border may focus convection as it oscillates across
this region through the end of the period. Large hail can be
expected with these storms, along with possible severe gusts.
Scattered strong/severe convection should spread into central NE by
late evening. Subsequent movement should allow this activity to
spread toward the mid MO River Valley late as LLJ veers into this
portion of the central US.
..Darrow/Jirak.. 09/16/2022
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