SPC Jun 27, 2025 0100 UTC Day 1 Convective Outlook

SPC 0100Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0755 PM CDT Thu Jun 26 2025

Valid 270100Z - 271200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR THE NEXT
COUPLE OF HOURS ACROSS EASTERN IOWA INTO SOUTHWESTERN WISCONSIN...

...SUMMARY...
Isolated wind damage and marginally severe hail will be the main
threats through late evening/early tonight from eastern Kansas into
southern Wisconsin, parts of the Mid-Atlantic and Appalachians, the
Texas Panhandle, and eastern Montana.

...Eastern KS to southern WI through late evening...
Convection has evolved into a line of storms from northwest MO into
eastern IA and southwest WI along a conglomerate outflow, in advance
of a weak midlevel trough approaching the upper MS Valley. 
Weakening buoyancy with the loss of daytime heating and weakening
vertical shear over time in the warm sector suggests that the storms
are likely past peak, though isolated wind damage will remain
possible for the next 2 hours or so before the storms weaken
sufficiently and the low levels stabilize. 

...Mid-Atlantic and Appalachians through 03z...
Scattered thunderstorms are ongoing in multiple small clusters from
central NC into VA/WV/MD and southern PA.  A few strong storms with
isolated wind damage will be possible through about 02-03z,
especially with storm mergers, before gradual stabilization of the
boundary layer brings an end to the largely diurnal severe threat.

...TX Panhandle through late evening...
A few storm clusters are ongoing across the central TX Panhandle to
the TX/NM state line.  Lingering steep low-level lapse rates, modest
vertical shear and storm/outflow mergers could maintain a marginal
severe threat for another few hours before buoyancy weakens and the
storms diminish.

...Eastern MT this evening...
Deep-layer vertical shear is not particularly strong and low-level
moisture is limited, but steep lapse rates through the low-midlevels
are sustaining a couple of stronger storm clusters across northeast
MT where low-level moisture is a bit richer.  There will remain
sufficient midlevel moisture/ascent downstream of an ejecting
midlevel trough to maintain the potential for thunderstorms for the
next several hours.  Isolated strong outflow gusts may occur with
the high-based convection into central MT, while isolated strong
gusts and marginally severe hail will remain possible this evening
across eastern MT.

..Thompson.. 06/27/2025

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