Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0744 AM CDT Sun Mar 24 2024
Valid 241300Z - 251200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
CENTRAL/SOUTHERN PLAINS...
...SUMMARY...
Large hail, damaging gusts and a few tornadoes are possible this
afternoon and evening over parts of the central/southern Plains.
...Synopsis...
The dominant mid/upper-level feature for this period will be a
major, synoptic-scale trough progressing eastward across the western
CONUS. Moisture-channel imagery indicates a closed cyclone,
centered over near-coastal southwestern OR, with troughing south-
southeastward roughly along the CA/OR coastline then west of Baja.
Ahead of that, a shortwave trough was evident over the lower
Colorado River Valley region. The OR low will dissipate today while
the basal shortwave trough pivots eastward across southern AZ to
eastern NM, reaching near a GCK-CVS axis by 00Z. A new closed
500-mb low should form this evening over the southwestern KS
vicinity, temporarily decelerating into erratic/cycloidal motion
over the same area until early day-2.
At the surface, a low was analyzed near LHX, with warm front across
northern KS to near MKC. The low should move little through most of
the day, remaining over the High Plains of eastern CO near the KS
line as the mid/upper shortwave trough approaches. The warm front
should pivot northwestward and merge with an initially separate
surface trough over NE. The low should shift eastward over western
KS tonight as a wave along a frontogenetic zone. By 12Z, the low
should reach north-central KS, with cold front trailing across the
TX Panhandle to east-central/northeastern NM, and warm front
northeastward to the YKN region then eastward over northern IA.
A dryline will become better-defined through the afternoon from a
frontal intersection in the GLD-ITR area to southwestern KS, then
across western OK to west-central/southwest TX, as moist advection
occurs to its east and diurnal heating/mixing to its west. A wind
shift and Pacific cold front, preceding the shortwave trough, will
move across eastern NM today and west TX this evening, overtaking
the dryline tonight. That combined boundary should shift eastward
across OK and north/central TX, reaching near a BVO-PRX-SAT line
then southwestward into northeastern Coahuila by 12Z tomorrow.
...Central/southern Plains...
Isolated to scattered thunderstorms are expected to develop near the
dryline this afternoon, some of which should become supercells
offering large hail and locally damaging to severe gusts as they
move obliquely across the narrow warm/moist sector. A couple
tornadoes also are possible as well, especially late afternoon into
early evening when a time window of overlap between surface-based
inflow and LLJ-maximized hodographs may develop. Tonight,
additional thunderstorms are possible as the dryline and Pacific
front merge, with isolated potential for all hazards.
Ahead of the ejecting shortwave trough, strong height falls, along
with left-exit region upper-jet forcing, midlevel DCVA, and
accompanying large-scale ascent/cooling, should reach the KS/OK
portion of the dryline around midafternoon. Those processes will
further reduce already cold mid/upper-level temperatures, especially
in areas between I-40 and I-70 before dark. A plume of elevated,
non-severe convection/precip should form in moistening, low-level
warm advection across parts of western OK into southern KS the next
few hours and shift eastward over those states today. Behind that,
and beneath the stronger cooling aloft, a narrow sector of diurnally
heated moist-sector air should develop -- perhaps only 40-70 nm wide
in OK.
However, even limited insolation should erode capping considerably
over OK and KS while midlevel lapse rates steepen, and moist
advection offsets mixing enough to maintain or even increase
boundary-layer moisture. Surface dewpoints in the low/mid 50s F
already are common from north TX to portions of south-central KS,
and should persist or increase somewhat. This will support 500-1200
J/kg MLCAPE in that post-precip/pre-dryline plume. 40-60 kt
effective-shear magnitudes are possible over parts of central/
southern KS and western OK, with very large hodographs (effective
SRH 300-600 J/kg). As the stronger cooling aloft and frontal
forcing extend over increasing moisture tonight, under nearly
boundary-parallel mid/upper flow, a line of strong/locally severe
convection may form between southern OK and the Edwards Plateau and
move eastward. Activity should weaken late overnight to near the
end of the period as it encounters a cooling/stabilizing boundary
layer.
..Edwards/Grams.. 03/24/2024
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