SPC AC 220559
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1259 AM CDT Wed Mar 22 2023
Valid 221200Z - 231200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF
NORTHEASTERN KANSAS EASTWARD TO NORTHERN INDIANA...
...SUMMARY...
Isolated/elevated strong to severe thunderstorms -- capable of large
hail -- are possible from far northeast Kansas eastward to northern
Indiana late tonight.
...Synopsis...
An upper trough across the western U.S. will move gradually eastward
with time, with the broader cyclonic flow field to encompass roughly
the western half of the country through the period. As this trough
advances, downstream ridging centered over the Gulf of Mexico will
amplify a bit, with a trend toward a bit of anticyclonic curvature
within the westerlies across the central and eastern U.S. with time.
At the surface, a low initially over the northern Minnesota vicinity
is forecast to shift quickly northeastward into -- and then across
-- Ontario through the period. Meanwhile, the trailing cold front
will become an increasingly west-to-east quasi-stationary front from
the central Plains into the Midwest. This boundary -- or more
specifically, a zone of warm advection focused to the cool side of
the front -- will focus a zone of elevated convection through the
period.
...Northeastern Kansas to northern Indiana...
Elevated showers and isolated/embedded thunderstorms are forecast to
be ongoing at the start of the forecast period across the northern
Missouri vicinity -- i.e. portions of the MRGL risk area. This
convection is forecast to shift eastward across the Midwest region
through the day.
Meanwhile, as a southwesterly low-level jet redevelops later this
evening, a gradual increase in new, elevated convection is expected,
in tandem with the increase in low-level warm advection atop a
surface-based stable layer.
With continued low-level theta-e advection within the 900 to 700 mb
layer, and some steepening of lapse rates aloft, the elevated
destabilization will likely be sufficient to support locally
strong/vigorous updrafts. This, combined with favorably strong
speed shear through the cloud-bearing layer, will likely support
locally severe storms, capable of producing large hail. With time,
an expanding convective cluster is forecast to spread eastward,
crossing central Illinois and eventually northern Indiana through
the end of the period.
..Goss/Lyons.. 03/22/2023
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
SPC AC 220559
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1259 AM CDT Wed Mar 22 2023
Valid 231200Z - 241200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM
CENTRAL/EASTERN OKLAHOMA INTO THE TEXAS HILL COUNTRY...
...SUMMARY...
Thunderstorms capable of hail, some very large, and damaging gusts
are possible Thursday afternoon through Friday morning across the
southern Plains.
...Synopsis...
Presence of western CONUS troughing and subtropical ridging over the
Gulf of Mexico will contribute to a belt of enhanced southwesterly
flow extending from northern Mexico northeastward across the central
Plains and Mid MS Valley early Thursday. A pair of shortwave troughs
will be embedded within this belt of stronger flow, one initially
near the Mid MO Valley and the other across southern AZ/northern
Mexico. Both shortwaves are expected to progress northeastward, with
the second shortwave moving through the southern High Plains during
the afternoon/evening, reaching KS/OK by early Friday morning.
The surface pattern Thursday morning will likely feature a low near
the northern IL/IN border vicinity, with a cold front extending
southwestward to another low over northwest TX. This front is
expected to move eastward/southeastward across the OH Valley, while
the southern portion moves more southeastward/southward across the
Ozark Plateau and much of OK. Guidance varies on the position of the
front over OK. Secondary surface cyclogenesis is anticipated over
the TX Low Rolling Plains Thursday afternoon, with the resulting low
then moving eastward into north TX.
...OH Valley Thursday morning...
Elevated thunderstorms will likely be ongoing near the surface low
across northern IL/northern IN early Thursday morning. Strong
vertical shear and steep mid-level lapse rates will be in place,
supporting the potential for a few strong updrafts capable of hail.
These early morning storms are expected to continue eastward, likely
outrunning most of the buoyancy as they move into OH during the late
morning.
...Southern Plains Thursday afternoon through Friday morning...
Low 60s dewpoints are expected be in place along the front
early Thursday morning, likely increasing into the mid 60s by the
late afternoon. Recent guidance has trended slower with the front,
keeping more of central and eastern OK ahead of the front during the
afternoon. Increasing low-level moisture coupled with modest daytime
heating should destabilize the airmass south of the
front by the late afternoon. This instability coupled with
convergence along the front is expected to result in thunderstorm
development, likely beginning over central OK. Vertical shear will
be strong, and the initial more cellular development may produce
large hail. Front-parallel deep shear should result in any
near-front development tracking northward over the front quickly,
likely limiting the surface-based warm sector development. Even so,
a brief temporal window for may exist for damaging gusts and/or a
tornado.
Thunderstorm development is also anticipated farther south, ahead of
the deepening surface low expected to move into northwest TX during
the early evening. A more cross-boundary vertical shear
vector is anticipated here, which could support a greater potential
for storms to stay surface-based. However, the presence of low-level
stability suggest an elevated storm mode, with the cold front acting
as the initiation mechanism. Like the storms farther north, hail is
the main severe threat, with some very large hail possible. As the
low and associated front continue eastward, storm coverage should
increase southward across the TX Hill Country/Edwards Plateau. Hail
and damaging gusts are possible with this line of storms as it moves
eastward toward central TX early Friday morning.
..Mosier.. 03/22/2023
WUUS02 PTSDY2
SPC AC 210724
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0224 AM CDT Tue Mar 21 2023
Valid 231200Z - 241200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM TEXAS HILL
COUNTRY ACROSS NORTHWEST/NORTH-CENTRAL TEXAS INTO SOUTHEAST
OKLAHOMA...
...SUMMARY...
Thunderstorms capable of hail, some very large, and damaging gusts
are possible Thursday afternoon through Friday morning across the
southern Plains.
...Synopsis...
The upper pattern early Thursday is forecast to consist of a western
CONUS trough and subtropical ridging centered over the Gulf of
Mexico. Enhanced mid-level westerly/southwesterly flow will persist
between these two features, extending from northern Mexico into the
Great Lakes region. A pair of shortwave troughs will be embedded
within the belt of stronger flow, one initially near the Mid MO
Valley and the other across southern AZ/northern Mexico. Both
shortwaves are expected to progress northeastward, with the second
shortwave moving through the southern High Plains during the
afternoon/evening, reaching KS/OK by early Friday morning.
The surface pattern Thursday morning will likely feature a low over
southern MI, with a cold front extending southwestward to another
low over northwest TX. The northern portion of the cold front will
remain progressive, moving eastward across the OH Valley. The
southern portion of the front (from northwest TX across OK) will
only make modest eastward/southeastward progress throughout the day,
as another low develops over west TX. This second low is then
expected to push northeastward along the front from Thursday evening
into Friday, moving from the Permian Basin into southeast OK. At it
does, an associated dryline will move eastward across southwest and
central TX.
...Southern Plains...
Low to mid 60s dewpoints are expected be in place along the front
early Thursday morning, likely increasing into the mid/upper 60s by
the late afternoon. This increasing low-level moisture coupled with
modest daytime heating should destabilize the airmass south of the
front by the late afternoon. Consequently, convergence along the
front is expected to result in thunderstorm development, likely
beginning over OK. Vertical shear will be strong, and the initial
more cellular development may produce hail. However, the slow-moving
front combined with the front-parallel orientation of the deep-layer
vertical shear suggests numerous storms and messy storm mode. This
could limit the overall severe potential across much of OK.
Farther south, thunderstorm development is anticipated ahead of the
deepening surface low expected to move into northwest TX during the
late afternoon/early evening. A more cross-boundary vertical shear
vector is anticipated here, supporting a greater potential for
supercells for at least a few hours. Very large hail is possible
with these storms as well as damaging gusts. As the low and
associated front continue eastward, storm coverage should increase
southward across the TX Hill Country/Edwards Plateau. Hail and
damaging gusts are possible with this line of storms as it moves
eastward toward the I-35 corridor early Friday morning.
..Mosier.. 03/21/2023
WUUS03 PTSDY3
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z
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