RSS Mesoscale Discussions from Storm Prediction Center
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1149 PM CST Tue Nov 11 2025
Valid 121200Z - 131200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Isolated thunderstorms will be possible along the coast of northern
California late tonight. No severe threat is forecast across the
U.S. today or tonight.
...DISCUSSION...
A mid-level ridge will move across the Rockies today, as a trough
translates eastward toward the West Coast. As large-scale ascent
associated with the approaching trough moves into northern
California late tonight, isolated thunderstorms will become possible
near the coast. Elsewhere across the continental U.S., thunderstorm
development is not expected today or tonight.
..Broyles/Weinman.. 11/12/2025
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SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1148 PM CST Tue Nov 11 2025
Valid 131200Z - 141200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not expected on Thursday or Thursday night.
...Discussion...
Very isolated thunderstorms remain possible, mainly across parts of
CA, on Thursday into Thursday night. The southern portion of a broad
upper trough will remain offshore of the CA coast through the
period. The low-level warm conveyor will be most pronounced Thursday
morning before waning somewhat as it gradually shifts southward in
CA. Mid-level lapse rates will remain weak to poor, but flimsy,
generally elevated buoyancy may sporadically develop within this
regime. Most CAM guidance suggests occasional bouts of more
pronounced low-topped convection should occur, supporting overall
thunder probabilities around 10 percent.
..Grams.. 11/12/2025
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SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0120 AM CST Wed Nov 12 2025
Valid 141200Z - 151200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not expected on Friday or Friday night.
...Discussion...
A closed upper low will fully cutoff from the westerlies by Friday
night, drifting offshore of southern CA. Bands of showers should
persist through much of the period in the onshore flow regime across
coastal southern CA. While mid-level lapse rates will remain weak,
scant elevated buoyancy should be maintained and may foster isolated
thunderstorms. MUCAPE will become negligible with eastern extent
over the Mojave Desert, likely yielding a confined thunder threat
through 12Z Saturday.
..Grams.. 11/12/2025
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0257 AM CST Wed Nov 12 2025
Valid 151200Z - 201200Z
...DISCUSSION...
...Lower Great Lakes/Upper OH Valley on D4/Saturday...
Amplification of a negative-tilt mid-level trough appears probable
from the Canadian Prairies towards the Northeast. Within the
left-exit region of a strengthening mid-level jet, convection should
increase towards late afternoon and especially into the evening
along a sharpening cold front that accelerates southeastward. With
only modified boundary-layer moisture return ahead of the front,
MLCAPE should be quite limited and spatially confined. But a
supercell wind profile combined with pronounced large-scale ascent
should be adequate for at least low severe probabilities.
...South-Central States on D6-8/Monday-Wednesday...
Latest guidance continues to converge towards the more consistent
EC-AIFS with the evolution of the closed low off the southern CA
coast at 12Z Saturday. Similar to yesterday's EC-AIFS, this should
become an open but compact wave as it ejects across the southern
Rockies to the central Great Plains by Monday. The southern
influence of the wave may overspread the northern periphery of
western Gulf moisture, rendering at least low severe probabilities.
This wave may largely dampen into Tuesday with the more consistent
EC-AIFS indicating a mid-level ridge building from the Gulf into the
Mid-MS Valley, in advance of a large-scale trough in the West. The
EC-AIFS hints at another potential cutoff/closed low situation,
albeit farther east than the prior wave. With the GFS also
supporting this scenario, severe potential in this pattern might
remain marginal and confined to TX. This is in contrast to other
guidance suggesting a more progressive wave interacting with the
western Gulf moisture plume.
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