LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1234 AM CDT Thu Mar 30 2023
Valid 301200Z - 311200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
CENTRAL AND SOUTHERN PLAINS...
...SUMMARY...
Isolated strong to severe storms are possible over parts of the
southern and central Plains Thursday evening and overnight.
...Central and Southern Plains...
Late-evening model guidance suggests upper low off the central CA
Coast will advance inland early in the period as the primary speed
max translates through the base of the trough across the lower CO
River Valley, increasing to near 100kt at 500mb over NM by the end
of the period. In response, LLJ will increase markedly across the
southern/central Plains which will prove responsible in transporting
higher-PW air mass from south TX into OK by mid day, ultimately with
significant moistening expected into a notable warm-advection
corridor over NE into southern MN during the overnight period. Early
this morning, 60s surface dew points are limited to the lower-middle
TX Coastal region; however, 60F dew points should reach the I-40
corridor around 31/00z, and I-70 over KS after midnight.
Current thinking is the warm sector will remain strongly capped much
of the period. However, strong boundary-layer heating within a
post-dryline environment will allow temperatures to warm into the
upper 70s across western KS and to near 80F over west TX by 21z.
This should weaken the cap such that isolated convection may develop
along the boundary. If so, strong shear will support sustained,
rotating storms. It's not entirely clear how many storms will evolve
along the dryline but supercells are possible if deep convection
materializes. Otherwise, elevated convection appears more likely
within the warm advection zone as it shifts north. Continued
moistening during the overnight hours across the southern Plains,
along with a weakening cap along the I-35 corridor may lead to
near-surface-based thunderstorms toward the end of the period. These
late-night storms would pose mostly a hail/wind threat, but a
tornado can not be ruled out.
Farther north, sharpening/moistening warm advection zone will serve
as the focus for a corridor of elevated convection from northern NE
into southwest MN. Forecast soundings suggest parcels should be
lifted near/above 850mb, but significant MUCAPE is evident (perhaps
in excess of 1000 J/kg). Hail is the primary risk with these
elevated storms after 31/00z.
..Darrow/Weinman.. 03/30/2023
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