RSS Mesoscale Discussions from Storm Prediction Center
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1021 AM CST Mon Nov 17 2025
Valid 171630Z - 181200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM CENTRAL AND
SOUTHERN MISSOURI INTO FAR WEST-CENTRAL ILLINOIS...
...SUMMARY...
Scattered thunderstorms should occur this evening and overnight
across parts of the northern/central Plains into the Ozarks and mid
Mississippi Valley. Isolated thunderstorms are also possible across
the Southwest and central California. A few strong thunderstorms
capable of producing hail may occur across parts of Missouri and
western Illinois late tonight.
...Ozarks into the Mid Mississippi Valley...
Shortwave trough currently moving across the central Rockies will
continue eastward across the central Plains, reaching the Mid MS
Valley by early tomorrow. Mass response ahead of this wave will
support continued low-level moisture advection, with low 60s
dewpoints likely reaching far southeast KS/far southwest MO by early
tomorrow morning. Mid 60s dewpoints will likely cover much of
eastern OK and western AR. The stronger large-scale ascent will
remain displaced west and north of the better low-level moisture,
and strong convective inhibition will preclude surface-based storms
throughout the period. However, persistent theta-e advection
throughout the warm conveyor will promote elevated buoyancy and the
potential for multiple rounds of elevated thunderstorms from the
Ozarks northeastward into the Mid MS Valley.
The initial round of deeper convection is expected across the
central MO vicinity this afternoon near the terminus of a 35-40 kt
low-level jet. Buoyancy will remain modest, but there is enough
shear within the cloud-bearing layer for updraft rotation and the
production of isolated hail. Continued warm-air advection will
result in further low-level warming and moistening, increasing the
elevated buoyancy tonight. This buoyancy coupled with glancing
large-scale ascent and a strengthening low-level jet could result in
additional thunderstorms farther south and west into southwest MO,
as well as increased coverage and intensity of any ongoing
thunderstorms from central MO into far west-central IL. Moderate to
strong vertical shear will continue to support rotation within any
deep and persistent updrafts, with an attendant threat for isolated
hail.
...CA into the Southwest...
Upper low currently off the northern CA coast will continue
southward throughout the day, ending the period over the San Luis
Obispo/Santa Barbara/Ventura county vicinity. Sporadic thunderstorms
are possible near this upper low, where cold mid-level temperature
and strong forcing for ascent are anticipated. A
non-lightning-producing band will move through the southern CA
coastal counties ahead of this low. Isolated lightning flashes are
also possible farther east within the warm conveyor over the Lower
CO River Valley and western AZ. Meager instability should limit the
threat for organized severe thunderstorms across the entire region.
..Mosier/Thornton.. 11/17/2025
Read more
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0149 PM CST Mon Nov 17 2025
Valid 172000Z - 181200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NORTHWEST
ARKANSAS INTO CENTRAL MISSOURI AND FAR WEST-CENTRAL ILLINOIS...
...SUMMARY...
Scattered thunderstorms should occur this evening and overnight
across parts of the northern/central Plains into the Ozarks and mid
Mississippi Valley. Isolated thunderstorms are also possible across
the Southwest and central California. A few strong thunderstorms
capable of producing hail may occur across parts of Missouri and
western Illinois late tonight.
...20Z Update...
A few modest changes to the general thunderstorm forecast as well as
the Marginal in southwest MO/northwest AR based on recent
observation/trends in guidance. The forecast otherwise remains on
track. See the previous discussion for additional information.
..Wendt.. 11/17/2025
.PREV DISCUSSION... /ISSUED 1021 AM CST Mon Nov 17 2025/
...Ozarks into the Mid Mississippi Valley...
Shortwave trough currently moving across the central Rockies will
continue eastward across the central Plains, reaching the Mid MS
Valley by early tomorrow. Mass response ahead of this wave will
support continued low-level moisture advection, with low 60s
dewpoints likely reaching far southeast KS/far southwest MO by early
tomorrow morning. Mid 60s dewpoints will likely cover much of
eastern OK and western AR. The stronger large-scale ascent will
remain displaced west and north of the better low-level moisture,
and strong convective inhibition will preclude surface-based storms
throughout the period. However, persistent theta-e advection
throughout the warm conveyor will promote elevated buoyancy and the
potential for multiple rounds of elevated thunderstorms from the
Ozarks northeastward into the Mid MS Valley.
The initial round of deeper convection is expected across the
central MO vicinity this afternoon near the terminus of a 35-40 kt
low-level jet. Buoyancy will remain modest, but there is enough
shear within the cloud-bearing layer for updraft rotation and the
production of isolated hail. Continued warm-air advection will
result in further low-level warming and moistening, increasing the
elevated buoyancy tonight. This buoyancy coupled with glancing
large-scale ascent and a strengthening low-level jet could result in
additional thunderstorms farther south and west into southwest MO,
as well as increased coverage and intensity of any ongoing
thunderstorms from central MO into far west-central IL. Moderate to
strong vertical shear will continue to support rotation within any
deep and persistent updrafts, with an attendant threat for isolated
hail.
...CA into the Southwest...
Upper low currently off the northern CA coast will continue
southward throughout the day, ending the period over the San Luis
Obispo/Santa Barbara/Ventura county vicinity. Sporadic thunderstorms
are possible near this upper low, where cold mid-level temperature
and strong forcing for ascent are anticipated. A
non-lightning-producing band will move through the southern CA
coastal counties ahead of this low. Isolated lightning flashes are
also possible farther east within the warm conveyor over the Lower
CO River Valley and western AZ. Meager instability should limit the
threat for organized severe thunderstorms across the entire region.
Read more
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1106 AM CST Mon Nov 17 2025
Valid 181200Z - 191200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE LOWER OHIO RIVER VALLEY...
...SUMMARY...
A few strong to severe storms are possible across portions of the
Lower Ohio Valley on Tuesday.
...Synopsis...
A positively tilted mid-level trough will move from the Midwest to
the Mid-Atlantic during the period on Tuesday. In its wake, ridging
will strengthen across the central CONUS ahead of a large trough
moving slowly east across southern California and into the
Southwest. A surface low and associated frontal features will begin
the period across the Ozarks and weaken through the day, becoming a
stalled, somewhat diffuse frontal zone near the Ohio River by 00Z.
...Lower Ohio Valley Region...
Elevated thunderstorms will be ongoing at the beginning of the
period across the Lower Ohio Valley within a region of strong
isentropic ascent on the nose of a 50 knot low-level jet. Small hail
and isolated large hail is possible with this morning activity.
Upper 50s to low 60s dewpoints will advect northward ahead of the
cold front in the wake of this morning activity. This may result in
a zone of surface or near surface based instability along the cold
front by early to mid afternoon. Moderate instability amid
steepening lapse rates and strong effective shear may result in a
few supercells capable of primarily large hail during the
afternoon/early evening. Where surface based instability is most
likely, some tornado threat will exist given favorable streamwise
vorticity in the lowest levels of the hodograph. Weak low-level
lapse rates should keep any tornado threat limited overall.
After 00Z, a cooling boundary layer and increasing heights aloft
from the west should bring an end to the severe weather threat
rather quickly. If afternoon thunderstorms grow upscale into an
eastward advancing line, some threat could persist into the evening
across central Kentucky, but even this threat should cease by
03-04Z.
..Bentley.. 11/17/2025
Read more
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0124 PM CST Mon Nov 17 2025
Valid 191200Z - 201200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE SOUTHERN PLAINS...
...SUMMARY...
Isolated severe storms are possible across parts of the southern
Plains on Wednesday evening into early Thursday.
...Synopsis...
On Wednesday, mid-level ridging will be present across much of the
eastern CONUS. A low-latitude trough will move slowly east across
the Southwest and start to emerge across the southern High Plains by
the end of the period.
...Southern Plains...
Instability will increase during the day Wednesday as rich low-level
moisture advects northwestward across Texas. By 00Z, the primary
trough will start to emerge over the southern Plains with height
falls spreading east, a strengthening low-level jet, and upper-level
diffluence above a surface front. This increasing forcing,
especially after 00Z, should result in scattered thunderstorm
activity from the Rio Grande to the Red River from the Edwards
Plateau to north-central Texas. Despite the unfavorable overnight
timing, some severe weather is possible given moderate instability
and shear combined with moderate to strong forcing for ascent.
...Southeast Arizona and southwest New Mexico...
Strong heating is expected across southeast Arizona and southwest
New Mexico Wednesday afternoon with weak instability forecast to
develop. A few strong storms capable of small hail and gusty winds
may develop within a strongly sheared environment during the
afternoon. At this time, instability appears too weak for severe
weather probabilities.
..Bentley.. 11/17/2025
Read more
