SPC Jun 25, 2025 0100 UTC Day 1 Convective Outlook

SPC 0100Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0757 PM CDT Tue Jun 24 2025

Valid 250100Z - 251200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL AND NORTHERN PLAINS...AND IN PARTS OF THE NORTHEAST...

...SUMMARY...
Large hail and severe wind gusts will be possible this evening in
parts of the central and northern High Plains. Isolated damaging
wind gusts will also be possible across parts of northern New York
into Vermont and New Hampshire early this evening.

...Central and Northern High Plains...
According to water vapor imagery, mid-level anticyclonic
southwesterly flow is currently present across much of the
north-central U.S. At the surface, a 1012 mb low is analyzed over
far eastern Colorado, with an upslope flow regime located over much
of the central and northern High Plains. Surface dewpoints within
the post-frontal airmass are mostly in the 60s F, which is
contributing to moderate instability over much of the region.
Scattered thunderstorms are ongoing along the western edge of the
moist airmass from eastern Colorado into southwest Nebraska.
Isolated storms are ongoing near the instability axis in central
Wyoming. As low-level flow increases early this evening, convective
coverage will likely be maintained as the storms move northeastward
into the lower elevations.

The most favorable environment for supercells appears to be in
central Wyoming. RAP forecast to the northwest of Casper, WY early
this evening have 0-6 km shear around 60 knots with 700-500 mb lapse
rates near 8.5 C/km. This may support a threat for isolated large
hail. Further to the southeast into parts of northeast Colorado and
southwest Nebraska, a cluster of strong to severe storms is ongoing.
Although a supercell will be possible within this cluster, the more
common storm type should be multicellular. This storm mode will
favorable severe gusts as the primary threat, especially with short
intense line segments.

Further to the east across parts of the central Plains, lower
Missouri Valley and southern Great Lakes, scattered thunderstorms
are ongoing near a front. Surface dewpoints in the upper 60s and
lower 70s F, combined with moderate instability and steep low-level
lapse rates, may be enough for marginally severe gusts early this
evening.

...Northern New York/Vermont, New Hampshire...
Mid-level westerly flow is currently located over much of the
Northeast. At the surface, a moist airmass is present across much of
the region with surface dewpoints mostly in the upper 60s to lower
70s F. An axis of moderate instability is analyzed from central New
York into western New England. To the north of the instability axis,
isolated to scattered storms are ongoing. In the vicinity of the
ongoing convection, the RAP has 20 to 25 knots of low-level flow,
0-3 km lapse rates near 7.5 C/km and moderate deep-layer shear. This
may be enough for severe wind gusts early this evening, associated
with the stronger multicells.

..Broyles.. 06/25/2025

StormPrep