SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0801 PM CDT Thu Apr 21 2022
Valid 220100Z - 221200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
CENTRAL KANSAS...SOUTHEAST NEBRASKA AND FAR SOUTHWEST IOWA...
...SUMMARY...
Large, damaging hail, severe gusts, and perhaps a tornado are
possible with any thunderstorm that can develop over parts of
south-central Kansas. Large hail is also possible across parts of
southeast Nebraska this evening into tonight.
...Southern and Central Plains...
Latest surface analysis shows a most airmass in place across much of
the southern and central Plains. Backed easterly upslope flow has
backed the moist airmass into parts of western Kansas where surface
dewpoints are now in the 60 to 65 F range. A warm front extends
eastward across south-central Kansas with a dryline in place from
southwest Kansas southward into northwest Oklahoma. Convective
initiation has taken place over the last hour to the east and
northeast of Dodge City along a bulge in the dryline where low-level
convergence is maximized. The storms will continue to take root in
the boundary layer over the next couple of hours. Although
large-scale ascent is relatively weak across the central Plains, the
strengthening low-level jet will provide support for continued
convective development.
The storms are located in a favorable thermodynamic environment,
with the RAP estimating MLCAPE in the 2000 to 3000 J/kg range and
700-500 mb lapse rates near 7.5 C/km. In addition, a mid-level speed
max in central Kansas is contributing to 0-6 km shear in the 40 to
50 knot range. This will support supercells with large hail.
Hailstones of greater than 2 inches in diameter will be possible,
and perhaps an isolated tornado threat could occur with the stronger
cells. The storms are expected to remain relatively isolated, moving
north-northeastward into north-central Kansas over the next few
hours. But the cap is forecast to re-strengthen by late evening
which should weaken any surface-based storms.
Further to the north into southeast Nebraska, model forecasts
suggest that elevated thunderstorm development will take place as
the low-level jet strengthens late this evening into the early
overnight period. RAP forecast soundings around 06Z in southeast
Nebraska have a sharp temperature inversion below 850 mb but show
steep lapse rates from 700 to above 300 mb. MUCAPE is forecast in
the 1200 to 1800 J/kg range, with effective shear near 60 knots.
This would be favorable for large hail with supercells that remain
elevated. The threat could develop northeastward into parts of the
mid Missouri Valley after midnight.
...Ozarks/Lower to Mid Missouri Valley...
Latest surface analysis shows a east-to-west warm front located
across south-central Missouri. A moist airmass is in place south of
the front across much of the Ozarks, where surface dewpoints are
mostly in the mid 60s F. The RAP currently has MLCAPE along and
south of the front around 1000 J/kg. A small area of thunderstorms
is ongoing near the front to the northeast of Springfield. These
storms will likely persist for a few more hours. Deep-layer shear
appears adequate for a marginal severe threat, with hail and a few
strong wind gusts possible. Further north, elevated thunderstorms
are expected to develop across northern Missouri and southern Iowa
tonight, in associated with a strengthening low-level jet. Enough
instability is forecast in the mid-levels for a hail threat with the
stronger cells.
..Broyles.. 04/22/2022
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