SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1227 PM CDT Thu Apr 28 2022
Valid 291200Z - 301200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM PORTIONS
OF FAR SOUTHEAST NEBRASKA INTO CENTRAL/EASTERN KANSAS AND
NORTH-CENTRAL OKLAHOMA...
...SUMMARY...
Severe thunderstorms capable of all hazards are possible Friday
afternoon into Friday night across portions of the southern and
central Plains into the lower Missouri Valley.
...Synopsis...
Very little change in the overall thinking of the forecast compared
to the earlier Day 2 outlook issuance. A strong mid- to upper-level
speed max will quickly move southeast from the eastern Great Basin
into the central/southern Plains during the period. In the low
levels, a surface low initially over the central High Plains will
develop east into central KS by mid afternoon before moving to
southeast SD by daybreak Saturday. A triple point over KS during
the day will feature a north-south dryline into the southern Great
Plains near/immediately west of the OK I-35 corridor. A cold front
will push east/southeast across KS and into OK Friday night.
...Southern NE south to OK/north TX...
Model guidance continues to show run-to-run consistency in the
evolution of a mid-level shortwave trough into the region during the
afternoon/evening. Increasing southerly low-level flow will advect
moisture northward beneath a stout capping inversion, as a warm
sector destabilizes from near the triple point southward along/east
of the dryline and becomes moderately to very unstable by early/mid
afternoon. Models show surface dewpoints into the lower to mid 60s
F over the central Great Plains to the mid-upper 60s from southern
KS southward. Increasing large-scale ascent will overspread this
region, with 30-60 m 12/hr 500 mb height falls expected by early
evening from I-40 in central OK northward into NE. Scattered
thunderstorms are forecast to develop as the cap erodes initially
near the triple point and a severe risk accompanying the stronger
storms. A couple of tornadoes and large to very large hail will be
the primary threats with these storms. Farther south from
south-central KS into parts of north TX, storm coverage will likely
become increasingly isolated, especially south of I-40. However,
impressive combination of low- to mid-level flow (700 mb flow 40-50
kt) amidst a very unstable boundary layer, will conditionally
support a very favorable environment for discrete supercells. Very
large to potentially giant hail (2-3+ inches in diameter) will
probably occur with any sustained storm (i.e., supercell). Hail,
along with the possibility for a couple of tornadoes (perhaps an
intense tornado), are expected beginning late in the afternoon
through the early-mid evening. Main questions at this time include
both storm coverage and moisture quality with the latter playing a
critical role in both storm coverage and tornado potential.
By early evening, coalescing of storms over KS/NE will likely lead
to upscale growth with some of these storms likely developing along
the front during the evening. Hail/wind will likely evolve to be
the main threats late in the evening with this risk perhaps
lingering into the overnight.
...Portions of northwest KS into western/central NE...
Strong to severe thunderstorms are expected to develop near the
deepening surface low across northwest KS by mid-afternoon.
Boundary-layer moisture will be lower quality compared to further
east, with dewpoints in the 50s to near 60 F. However, very steep
midlevel lapse rates will support moderate instability. Effective
bulk shear values will support initial supercells capable of large
to very large hail. With time, this convection may develop into
bowing line segments as convection shifts northeast into NE.
..Smith.. 04/28/2022
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