SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0259 PM CDT Sun Apr 24 2022
Valid 242000Z - 251200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
WEST TEXAS...NORTH TEXAS/SOUTHERN OKLAHOMA...AND THE MID MISSISSIPPI
VALLEY INTO LOWER MICHIGAN...
...SUMMARY...
Scattered large hail, isolated severe wind gusts, and a brief
tornado remain possible across parts of the southern Plains this
afternoon and evening. Scattered damaging winds, marginally severe
hail, and a tornado or two may also occur this afternoon into early
evening from the Mid Missouri Valley to Lower Michigan.
...20Z Update...
Severe probabilities have been compressed/reduced behind an ongoing
cluster of thunderstorms across north TX and southern OK. A cold
front draped over this region will continue to move slowly southward
this afternoon and evening. The best potential for isolated severe
hail and damaging winds should remain focused along and south of
this boundary as convection spreads eastward over the next several
hours.
Otherwise, a thunderstorm has recently initiated in the vicinity of
the dryline/cold front intersection in west TX. Greater instability
and steep mid-level lapse rates are present over this region
compared to farther east in TX. 35-45 kt of deep-layer shear will
likely support supercells with any thunderstorms that can be
sustained as lingering convective inhibition gradually erodes. Large
hail, with some potential for 2+ inch hail, and damaging winds
should be the main threats with this activity through the evening as
it develops slowly east-southeastward. Reference Mesoscale
Discussion 557 for additional details.
Farther north, isolated to scattered convection has developed this
afternoon from parts of central IL to Lower MI. Although the
thermodynamic environment across this region remains marginal owing
to limited low-level moisture, deep-layer shear is fairly strong.
Some attempt at a more cellular mode has recently been observed.
Isolated damaging winds, marginally severe hail, and perhaps a
tornado should remain a threat with these thunderstorms through the
early evening. See Mesoscale Discussions 556/558 for more
information on the near-term severe threat across this region.
..Gleason.. 04/24/2022
.PREV DISCUSSION... /ISSUED 1130 AM CDT Sun Apr 24 2022/
...North Texas/southern Oklahoma...
Storms are expected to persist and further develop/intensify through
the afternoon within a west/southwest-east/northeast-oriented
corridor across north Texas and southern Oklahoma. Bouts of large
hail should be the primary overall risk, although damaging wind
potential may increase as the boundary layer warms ahead of the
southeast-advancing front and any clustering of storms.
...West Texas...
Near the Concho to Lower Pecos Valleys and the western Edwards
Plateau, a few discrete supercells may develop during the early
evening along the trailing portion of the front intersecting with
the dryline. Despite weak low-level flow, 40-50 kt effective bulk
shear in conjunction with MLCAPE around 2000 J/kg should support a
threat for large hail. It is plausible that a slow-moving cluster
may shift east-southeast along the composite convective outflow/cold
front during the mid to late evening with a threat for isolated
severe wind gusts before convection wanes tonight.
...Midwest including Illinois to Lower Michigan...
A relatively moist air mass precedes an eastward-moving cold front
with a semi-narrow regional axis of upper 50s/lower 60s F surface
dewpoints. Limited mid-level height falls will occur with the
primary upper-level trough centered to the north along the
international border, but one or more weak MCVs will influence the
region. Overall convergence will remain muted and cloud cover will
remain semi-prevalent across the warm sector, but a diurnal
intensification of storms is nonetheless probable across the
southern and eastern halves of Illinois into western/northern
Indiana and Lower Michigan. While transient supercells are possible,
much of the activity should tend to evolve into linear bands and
clusters. Strong to isolated severe wind gusts may result in
scattered damaging winds, but a tornado or two could also occur
given the moderately strong low-level shear/SRH. The overall severe
threat should diminish after sunset. For additional short-term
details, see Mesoscale Discussion 555.
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