Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0736 PM CDT Sun Jun 22 2025
Valid 230100Z - 231200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE GREAT PLAINS AND UPPER MISSISSIPPI VALLEY...
...SUMMARY...
Isolated to scattered thunderstorms will continue this evening
across parts of the northern Plains and Upper Mississippi Valley,
some of which could produce large hail, damaging wind gusts and
tornadoes. Storms associated with marginally severe gusts and hail
will also be likely across parts of the southern and central Plains.
...Central and Northern Plains/Upper Mississippi Valley...
A mid-level trough is evident on water vapor imagery over the
northern Rockies, with southwest flow located over the northern
Plains and upper Mississippi Valley. At the surface, a 997 mb low is
located in far southeast North Dakota with a cold front extending
southwestward from the low into eastern South Dakota and central
Nebraska. Surface dewpoints ahead of the front are in the 70s F
across the upper Mississippi Valley, with mostly 60s F located over
parts of the mid Missouri Valley and central Plains. The RAP has
moderate to strong instability analyzed ahead the front, with the
highest instability in north-central Minnesota where MLCAPE is
estimated to be near 4000 J/kg. Scattered thunderstorms are ongoing
near the front in north-central Nebraska, and in the post-frontal
airmass in western Nebraska. This activity is being supported by
subtle shortwave trough moving through the central High Plains. As
low-level flow ramps up this evening, storm coverage is expected to
gradually increase, with the storms moving northeastward into
southern and eastern South Dakota later this evening. Additional
storms appear likely to develop over parts of Minnesota.
Near the front from eastern South Dakota into northwest Minnesota,
RAP forecast soundings suggest that 0-6 km shear will be mostly
between 30 and 40 knots this evening. In addition, 700-500 mb lapse
rates will be near 8 C/km. This environment should support
supercells with large hail. Hailstones greater than 2 inches in
diameter will be possible, mainly over west-central and northern
Minnesota where the strongest instability is analyzed. Some
short-term models also show potential for short intense line
segments. If a line can become organized and remain persistent, the
potential for severe gusts would be pronounced, with wind gusts
above 70 mph possible. A tornado threat will also be likely with
supercells, and bowing line segments.
...Southern and Central High Plains...
Southwest mid-level flow is evident on water vapor imagery over the
southern and central High Plains. At the surface, a 998 mb low is
located in far southwest Nebraska with a moist airmass located to
the south and southeast of the low across much of the central and
southern High Plains. Scattered thunderstorms are ongoing from
eastern New Mexico into the Texas Panhandle. The storms are being
supported by a subtle shortwave trough evident on water vapor
imagery. The storms will continue to move eastward into the stronger
instability this evening. The Amarillo 00Z sounding has very steep
low to mid-level lapse rates, with surface dewpoints in the 60s and
about 2000 J/kg of MLCAPE. This should support a threat for isolated
severe gusts this evening. Hail will also be possible with the
stronger cores. The severe threat could expand north-northeastward
into western Kansas as low-level flow increases this evening.
..Broyles.. 06/23/2025
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