RSS Mesoscale Discussions from Storm Prediction Center
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1054 PM CST Wed Nov 26 2025
Valid 271200Z - 281200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
The risk for thunderstorms appears negligible across much of the
U.S. today through tonight.
...Discussion...
Models indicate that an initially significant, and now occluding,
cyclone will gradually weaken across Quebec today through tonight,
as a weaker secondary cyclone also occludes across and
north-northeast of the Canadian Maritimes. In mid-levels, it
appears that large-scale troughing will be reinforced and undergo
amplification while progressing into and across the Atlantic
Seaboard, in response to a pair of initially digging short wave
perturbations across and east of the Mississippi Valley. As this
occurs, a notable associated surface cold front is forecast to
progress away from the Atlantic Seaboard, and through much of the
remainder of the Florida Peninsula and Gulf Basin.
Within split westerlies emanating from the northern and mid-latitude
Pacific, a pair of short wave impulses are forecast to dig inland
across the Cascades and Canadian Rockies, downstream of building
larger-scale mid/upper ridging. However, it appears that generally
stable conditions will be maintained across much of the West, in
addition to most areas east of the Rockies.
...Florida Peninsula...
Downstream of the amplifying large-scale mid-level trough axis,
models continue to indicate that one area of developing large-scale
forcing for ascent may overcome mid-level inhibition and support a
couple of generally weak thunderstorms across the Lower Florida Keys
into southeastern Florida coastal vicinities this morning into
afternoon. In the presence of another developing area of
large-scale ascent, weak destabilization may also support at least
lower threshold probabilities for thunderstorms, ahead of the
southward advancing cold front across interior central into east
central coastal portions of the peninsula this afternoon.
...Lower Great Lakes...
Cold air overspreading the relative warm waters of Lakes Erie and
Ontario may contribute to thermodynamic profiles increasingly
conducive to convection capable of producing occasional lightning,
particularly as temperatures cool below -20 to -25 C in the 700-600
mb layer this afternoon into tonight, based on forecast soundings.
..Kerr.. 11/27/2025
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SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1254 AM CST Thu Nov 27 2025
Valid 281200Z - 291200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
A few thunderstorms are possible over the southern Plains tomorrow
(Friday) night into early Saturday morning. Severe thunderstorms are
not currently expected.
...Synopsis...
Surface high pressure across much of the Interior West, as well as
the northern and eastern CONUS, will limit thunderstorm potential in
these regions due to static stability. However, the rapid approach
of a mid-level trough will encourage lee cyclogenesis over the
southern Plains tomorrow (Friday). As the surface low materializes
over western OK during the day, modest low-level moisture will
advect northward with the aid of a 40-50 kt southerly low-level jet.
7-8 C/km mid-level lapse rates are expected to overspread the
aforementioned low-level warm-air advection, promoting
destabilization Friday night/early Saturday morning atop a stable
boundary layer. This elevated buoyancy, characterized by 500-1000
J/kg thin MUCAPE constrained above 700 mb, will support nocturnal
thunderstorm development over portions of the southern Plains, when
the primary upper support with the approaching mid-level trough
arrives. Given strong vertical wind shear (e.g. elongated
hodographs), a few of the stronger storms may produce hail. However,
given limited elevated MUCAPE, the confidence in the coverage of
more than sparse severe hail is too low for the introduction of
severe probabilities at this time.
..Squitieri.. 11/27/2025
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