RSS Mesoscale Discussions from Storm Prediction Center
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0142 PM CST Sat Nov 15 2025
Valid 152000Z - 161200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS EASTERN OHIO
INTO NORTHERN WEST VIRGINIA INTO WESTERN PENNSYLVANIA...
...SUMMARY...
Isolated severe gusts are possible across parts of the upper Ohio
Valley late this afternoon and evening.
...20z Update...
No changes are needed to the current D1 Convective Outlook. A few
occasional stronger cores have been noted near the warm front across
western New York into southern Ontario. Overall, limited moisture
and poor thermodynamics have limited the severe threat. Further
south across the upper Ohio Valley, additional convective
development is expected along the front later this afternoon. Though
mid-level cloud cover has prevailed, dew points in the 50s are
observed across Ohio into northern West Virginia and Pennsylvania.
Here a narrow region of weak instability overlapping with increasing
forcing for ascent will support potential for locally damaging
gusts.
..Thornton.. 11/15/2025
.PREV DISCUSSION... /ISSUED 1030 AM CST Sat Nov 15 2025/
...Upper Ohio Valley...
Water-vapor imagery late this morning shows a mid-level trough over
the Upper Great Lakes. This mid-level trough will quickly move east
into the Lower Great Lakes vicinity by early evening with an
attendant increase in large-scale forcing for ascent expected to
spread across the Upper OH Valley and Lower Great Lakes regions.
Although primary cyclone development will occur from eastern Lake
Superior eastward to the VT/Quebec region, a cold front will push
southeastward across the Great Lakes into the central Appalachians
during the period. Despite low-level theta-e advection into the
region from the lower OH Valley, the overall magnitude of
destabilization will be limited in part due to considerable cloud
cover thwarting greater heating. Models show surface dewpoints
rising into the upper 50s beneath a capping inversion by late
afternoon. Weak instability and the aforementioned forcing will aid
in the eventual development of isolated to scattered thunderstorms
probably in the form of one primary band of convection towards early
evening. Strong to locally damaging wind gusts are the primary
concern, with convection expected to weaken with eastward extent
into central PA this evening due to meager instability with the loss
of daytime heating.
...Southern California/Southwest...
A potent mid-level speed max translating through the base of a
trough west of southern CA/Baja CA will move into the Mojave Desert
later today. Pockets of weak instability will likely develop today
and favor isolated bouts of deeper convection across southern CA
into the lower CO River Valley. Despite strengthening mid-level
flow fields, muted lapse rates will likely limit storm intensity and
the propensity for strong/locally damaging gusts.
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SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0118 PM CST Sat Nov 15 2025
Valid 171200Z - 181200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Scattered thunderstorms are possible Monday evening into early
Tuesday morning across parts of the central Plains into the Ozarks.
Severe thunderstorm potential appears low.
...Discussion...
The mid-level shortwave trough associated with thunderstorm activity
in the central Rockies on Sunday will advance east across the Plains
and into the Midwest on Monday. Isentropic ascent will increase
across the eastern Plains and Ozarks as the low-level jet
strengthens ahead of the mid-level trough. Weak elevated instability
may result in scattered thunderstorms along the warm frontal zone
Monday evening/overnight. A few of these thunderstorms may be strong
enough for small hail, but uncertainties regarding moisture
return/destabilization preclude the need for severe weather
probabilities at this time.
..Bentley.. 11/15/2025
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