Severe Storm Outlook Narrative (AC) Issued by NWS
000
ACUS02 KWNS 120600
SWODY2
SPC AC 120558
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1258 AM CDT Tue Mar 12 2024
Valid 131200Z - 141200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER
MO VALLEY...
...SUMMARY...
Severe thunderstorms capable of large to very hail and a tornado or
two are possible across the Lower Missouri Valley from Wednesday
afternoon through Wednesday night.
...Synopsis...
Deep upper troughing is expected to be in place across the western
CONUS early Wednesday morning, with strong mid-level flow extending
from the Pacific Northwest into the Southwest states throughout the
western and southern periphery of the trough. Several shortwave
troughs will be embedded within this larger trough, including one
that is forecast to eject northeastward through the central Plains
during the day.
Surface low associated with this shortwave is expected to progress
into the central Plains just ahead of its parent shortwave, likely
ending the period near the KS/NE/MO border intersection. A dryline
will accompany this low, gradually pushing eastward across KS and OK
throughout the day and into the early evening before then stalling
until the cold front arrives early Thursday morning. A warm front is
also expected to extend southeastward from this low, with this front
gradually moving northward throughout the day. By 00Z this warm
front is expected to extend from the low over north-central KS
east-southeastward into central MO. Thunderstorm development is
anticipated in the vicinity of the surface low and warm front, with
isolated development possible south along the dryline as well.
...Lower MO Valley...
Dewpoints will likely be in the mid 50s across much of eastern KS by
the late afternoon, possibly reaching into far southeast NE. Some
locally higher dewpoints are possible along the warm front as well.
These dewpoints, combined with surface temperatures in the mid 70s
and cold mid-level temperatures, should be sufficient for airmass
destabilization. Large-scale ascent attendant to the approaching
shortwave trough coupled with low-level convergence near the surface
low and warm front are expected to provide the lift needed for
convective initiation. Initiation is currently expected to occur in
the 21Z to 00Z time frame over north-central/northeast KS. The
strongest mid-level flow will likely be displaced south of the
region, but vertical shear should still be strong enough for
supercells. Given the steep mid-level lapse rates some large to very
large hail is possible. Veering low-level wind profiles with height
also suggest some tornado potential exists, particularly near the
warm front where low-level southeasterlies are more likely.
Thunderstorm coverage will likely grow during the evening as the
low-level jet strengthens, with a warm-air advection increasing as
well. These storms would likely be elevated north of the warm front,
with steep mid-level lapse rates and moderate vertical shear
supporting hail with any more mature updrafts.
...Southeast KS...Central/Eastern OK...Far Northeast TX...
A more conditional severe threat exists in this region versus
farther north across the Lower MO Valley. Here, upper 50s to low 60s
dewpoints are likely, but warmer mid-level temperatures look to cap
the airmass, precluding widespread destabilization. Even so,
convergence along the dryline may be able to overcome this
inhibition in isolated instances, and the overall environmental
conditions support supercell thunderstorms capable of all severe
hazards if convective initiation is realized.
..Mosier.. 03/12/2024
$$