spc ac 180505
day 2 convective outlook
nws storm prediction center norman ok
1205 am cdt sat jul 18 2026
valid 191200z - 201200z
...there is a slight risk of severe thunderstorms across the
northern plains...and parts of north carolina into southeast
virginia...
...summary...
isolated to widely scattered strong to severe thunderstorms may pose
a risk for damaging wind gusts across portions of the southern
appalachians to the coastal carolinas/southeast virginia vicinity on
sunday. strong to severe storms may also develop across parts of
eastern montana into north dakota and minnesota.
...southern appalachians to the coastal carolinas/southern va...
an upper trough over the eastern u.s. will persist on sunday. at the
surface, a cold front will develop southward across va toward the
nc/va border. near and south of this front, a very moist airmass
will be in place (70s f dewpoints), and strong heating will foster a
corridor of moderate instability. deep-layer flow will remain
modest, with effective shear values typically only around 20-25 kt.
however, steep low-level lapse rates and pw values near/above 2
inches are present in forecast soundings. storms that develop will
pose a risk for wet microbursts, and a greater wind risk may evolve
closer to the cold front where sufficient clustering occurs.
...northern plains into northern mn...
a compact upper low/shortwave trough over alberta will develop
east/southeast on sunday, emerging over the canadian prairies and
northern plains. as this occurs, a belt of strengthening
west/northwesterly mid/upper flow will overspread the region. a
surface cold front will develop southeast across eastern/southern mt
during the afternoon, and the dakotas during the evening/overnight
hours. southerly low-level flow ahead of this feature will transport
modest moisture northward into the area. steep midlevel lapse rates
will support 1000-2000 j/kg mlcape amid 40+ kt effective shear
magnitudes. initial convection may be cellular, posing a risk for
isolated large hail. given steep low-level lapse rates, strong
outflow winds also will be possible, and some potential for a bowing
cluster of storms is possible if sufficient storm coverage occurs
ahead of the cold front from southern/eastern mt into the dakotas
through evening. overnight storms may persist eastward into northern
mn, though severe potential is less certain across this area given
stronger capping.
..leitman.. 07/18/2026
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note: the next day 2 outlook is scheduled by 1730z