Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1241 AM CDT Mon Aug 11 2025
Valid 111200Z - 121200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN HIGH PLAINS AND RED RIVER VALLEY OF THE NORTH...
...SUMMARY...
Strong thunderstorms accompanied by at least some risk for severe
wind and hail may impact parts of eastern New Mexico into the Texas
South Plains, as well as parts of eastern North Dakota into
northwestern Minnesota, late this afternoon and evening.
...Synopsis...
Late-evening water-vapor imagery depicts an upper trough/vorticity
maximum settling into the southern/central High Plains. This feature
is expected to stall and weaken over the Plains over the next 24
hours with a gradual abatement of mid-level flow. To the north, a
pronounced mid-level wave is apparent over the Canadian
Rockies/Prairies. This feature will continue southeastward into the
northern Plains and upper Mississippi River Valley through tonight.
Strong/severe thunderstorm chances will largely be attendant to
these mid-level features.
...Southern High Plains...
05z surface observations across the southern Plains reveal a
composite frontal zone/outflow boundary draped from far northeast NM
through the TX/OK Panhandles and roughly along the OK/KS border.
This boundary will likely be displaced southward as a result of
early-morning convection, though precisely where this boundary
resides by peak heating is somewhat uncertain. Regardless,
thunderstorm development along this boundary is expected by late
afternoon/early evening. To the south of this boundary, easterly
winds on the northern periphery of a weak surface low over the
Permian Basin will maintain an upslope flow regime along the eastern
slopes of the Sacramento, Sandia Manzano, and Sangre de Cristo
Mountains. Modest westerly mid-level flow atop easterly low-level
winds should yield sufficient deep-layer shear for a few organized
storms, including a supercell or two. With time, upscale growth
and/or merging with additional convection developing along the
surface boundary will promote an increased threat for severe gusts
through early evening. While convection is expected northeastward
along much of the boundary from central OK into adjacent portions of
KS/MO, weaker mid-level winds with eastward extent casts doubt on
the potential for a robust severe threat (aside from occasional
strong wet downbursts).
...Red River Valley of the North...
Modest surface cyclogenesis is anticipated across the central
Canadian Prairies over the next 24 hours as the mid-level wave
approaches the international border. An attendant cold front is
forecast to spread across the northern Plains through late afternoon
and will impinge on a plume of seasonal low-level moisture. While
mid-level lapse rates will remain modest (around 6-7 C/km), adequate
buoyancy should be in place for deep convection. 30-40 knot
mid-level flow should provide sufficient deep-layer shear for
organized storms, though the marginal thermodynamic environment will
likely be a modulating factor in overall storm intensity. Strong
frontal forcing should promote upscale growth through the evening
hours with an associated threat for damaging/severe winds.
..Moore/Darrow.. 08/11/2025
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