still slight/marginal for most of the metro
But this has to be one of the most bullish SPC discussions ever
As the mid-level jet ejects
northeastward across the southern High Plains this afternoon and
evening, a tornado outbreak is likely across the southern Plains.
The tornado outbreak is expected to continue into the overnight
period.
This event should result in a significant threat to life and
property. RAP forecast soundings late this afternoon along the instability
corridor from Childress, Texas northeastward to Clinton, Oklahoma
show MLCAPE values of 3000 to 4500 J/kg with 0-6 km shear in the 50
to 65 kt range. In addition, hodographs are large and looped with
0-1 km shear values in the 30 to 40 kt range. This environment
should be very favorable for supercells and tornadoes. 0-3 km
storm-relative helicities are forecast to steadily increase from
about 300 m2/s2 in the late afternoon to about 450 m2/s2 by early
evening as an anomalously strong low-level jet becomes better
focused.
This will be ideal for a tornado outbreak with strong
tornadoes upstream and to the west of the low-level jet.
The current thinking concerning the details is that the first round
of severe storms will begin early as thunderstorms initiate in west
Texas and move northeastward into the eastern Texas Panhandle by mid
to late morning. Initially, large hail will be the main threat but
as these storms mature, tornadoes will be possible with the stronger
and more dominant cells. Additional supercells with tornado
potential are expected to initiate near the warm front in western
and central Oklahoma. A tornado threat will transition to large hail
and wind damage as the storms move into Kansas to the north side of
the boundary. This first round of severe storms is forecast to move
northeastward, away from the warm sector, allowing for the
development of extreme instability during the mid to late afternoon
from northwest Texas into southwest Oklahoma.
The second round of severe storms is expected to start during the
late afternoon as repeat initiation takes place in west Texas. Rapid
supercell formation is forecast along the I-27 corridor from the
vicinity of Lubbock northward to just south of Amarillo. A cluster
of tornadic supercells is then forecast to move northeastward into
northwest Texas and the southeastern Texas Panhandle during the
early evening. Additional tornadic supercells are forecast to
rapidly develop in southwest Oklahoma and move northeastward into
west-central Oklahoma.
At that time, the strengthening low-level jet
will couple with a highly progressive and seasonably strong
mid-level jet, making conditions favorable for long-track strong
tornadoes and possibly violent tornadoes.
