spc ac 200738
day 3 convective outlook corr 1
nws storm prediction center norman ok
0238 am cdt sat jun 20 2026
valid 221200z - 231200z
...there is a marginal risk of severe thunderstorms from the central
high plains and southern plains to the mid-south and into the
carolinas and mid-atlantic....
corrected for capitalization in the summary
...summary...
isolated strong to severe storms are expected along a frontal zone
that extends from the mid-atlantic to the mid-south and southern
plains and into the central high plains on monday.
...synopsis...
a flat ridge is forecast across the western conus with broad
cyclonic flow from the southern plains to the mid-atlantic. within
this zone, several embedded mid-level shortwave troughs are
expected, the strongest of which will move from the ohio valley to
the mid-atlantic during the day monday. a weak surface low will
likely be associated with this lead shortwave trough with an
additional lee trough, likely across the southern high plains. a
frontal zone will extend between these 2 features and act as the
primary focus for storm development through the period on monday.
...central/southern plains...
a mcs should be ongoing at the beginning of the period across parts
of oklahoma on the nose of the low-level jet. an outflow boundary
will likely extend westward from this mcs into parts of northwest
texas and into the texas panhandle.
very strong to extreme instability is forecast across the southern
plains on monday with dewpoints in the mid to upper 70s and steep
lapse rates. model guidance is consistent showing a weak mid-level
shortwave trough emerging across the southern plains by 00z tuesday
with 30 to 35 knots of mid-level flow. the combination of this
shortwave trough and the potential for an outflow boundary
intersecting the dryline may result in a more focused area of severe
potential monday afternoon/evening. however, due to the mesoscale
nature of this potential, confidence is not high enough to add a
slight risk at this time.
...mid south...
moderate to strong instability is forecast to develop ahead of the
mcs across oklahoma and arkansas monday morning. given the very
moist airmass, inhibition should be eroded by mid-day. therefore,
reintensification of the morning mcs or additional development to
the east along the front (likely a combination of both) is expected
from near the red river to northern mississippi. this strong
instability, combined with modest shear, will support some damaging
wind threat with a southeastward moving cluster of storms monday
afternoon/evening.
...carolinas to the mid-atlantic...
a moist airmass will move into the carolinas and mid-atlantic on
monday ahead of an eastward moving cold front. mid-level lapse rates
will be weak which will limit overall instability, but moderate
shear and sufficient instability, combined with steep low-level
lapse rates will support some damaging wind threat monday
afternoon/evening. in addition, a smaller area of greater low-level
shear may exist closer to the surface low across northern virginia
and vicinity, which could have a localized region of greater tornado
threat.
..bentley.. 06/20/2026
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note: the next day 3 outlook is scheduled by 1930z