LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1251 AM CDT Sun Oct 23 2022
Valid 231200Z - 241200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE CENTRAL PLAINS TO THE UPPER MISSISSIPPI VALLEY...
...SUMMARY...
Severe thunderstorms capable of damaging gusts and hail are possible
from the central Plains into the Upper Mississippi Valley Sunday
evening into early Monday morning. Additional isolated severe
thunderstorms may produce strong gusts and hail across parts of the
southern Plains early Monday morning.
...Central Plains to Upper MS Valley...
Upper trough is advancing inland across the Intermountain West early
this morning. Mid-level flow will increase across the southern
Rockies early in the period then a 500mb speed max (90kt+) will
translate into eastern SD by 24/12z. In response to this speed max,
lee cyclone will shift east into the central Plains by late
afternoon then lift north across the upper Red River Valley after
midnight.
Boundary-layer moisture is not particularly rich across the warm
sector at this time with 60F surface dew points just now to DAL.
However, it appears 50s dew points will extend along a sharpening
dry line from KS into southeast SD by peak heating where surface
temperatures will likely warm into the lower-mid 80s with
near-dry-adiabatic lapse rates in the lowest 3 km of the sounding.
Despite the somewhat marginal moisture (PWs around 1 inch), forecast
soundings exhibit ample buoyancy for the potential for isolated
thunderstorms, as convective temperatures are breached ahead of the
boundary. Additionally, very strong wind fields favor organized
rotation, and a few supercells are possible. With 50kt southerly
flow forecast in the lowest 1km AGL, relatively low sub-cloud RH
values may enhance the wind potential with this late afternoon
convection. Primary large-scale forcing, in association with the
left exit region of the aforementioned jet, will shift north during
the evening, and increasing warm advection is expected to contribute
to elevated convection during the overnight hours. Hail is the
primary risk with this activity, but some wind potential is also
possible as moisture increases across the Red River Valley (of the
North) late in the period ahead of the well-defined surface low.
...Southern Plains...
Low-latitude trough currently observed off the Baja Peninsula is
forecast to eject northeast across northern Mexico toward far west
TX late in the period. Forcing along the leading edge of this
feature should approach the western plume of boundary-layer Gulf
moisture over west TX late. Low-level confluent flow favors
scattered thunderstorm development by sunrise Monday. RAP forecast
sounding for ABI at 24/12z exhibits SBCAPE on the order of 600 J/kg
with a fairly moist profile/modest lapse rates through 9 km.
Forecast shear favors a potential squall line developing into the
early day2 period. Wind/hail are the primary risks with this
activity.
..Darrow/Lyons.. 10/23/2022
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