RSS Mesoscale Discussions from Storm Prediction Center
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Thu Oct 02 2025
Valid 021630Z - 031200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not expected across the continental U.S.
today or tonight.
...Discussion...
An upper trough will continue to amplify and build southward along
the West Coast, with preceding height falls over the Great Basin and
northern Intermountain West. Sufficient moisture will exist ahead of
a cold front, with marginal buoyancy supportive of isolated
thunderstorms later today and especially into tonight from the
Sierra and Great Basin toward the northern Rockies. A couple of
stronger storms could materialize, but severe storms are not
expected. Elsewhere, thunderstorms will also be possible across the
Upper Midwest and Lake Superior vicinity, in addition to Florida and
the Lower/Middle Mississippi Valley.
..Guyer/Wendt.. 10/02/2025
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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0255 PM CDT Thu Oct 02 2025
Valid 022000Z - 031200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not expected across the continental U.S.
today or tonight.
...20Z Update...
The forecast remains on track, and minimal changes were made with
this update. See the previous discussion below for details.
..Weinman.. 10/02/2025
.PREV DISCUSSION... /ISSUED 1130 AM CDT Thu Oct 02 2025/
...Discussion...
An upper trough will continue to amplify and build southward along
the West Coast, with preceding height falls over the Great Basin and
northern Intermountain West. Sufficient moisture will exist ahead of
a cold front, with marginal buoyancy supportive of isolated
thunderstorms later today and especially into tonight from the
Sierra and Great Basin toward the northern Rockies. A couple of
stronger storms could materialize, but severe storms are not
expected. Elsewhere, thunderstorms will also be possible across the
Upper Midwest and Lake Superior vicinity, in addition to Florida and
the Lower/Middle Mississippi Valley.
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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1145 AM CDT Thu Oct 02 2025
Valid 031200Z - 041200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE NORTHERN ROCKIES INTO THE FOUR CORNERS...
...SUMMARY...
Isolated severe gusts and perhaps a couple instances of hail may
occur across the northern Rockies into the Four Corners tomorrow
(Friday).
...Synopsis...
A pronounced mid-level trough will progress across the Interior West
while upper ridging persists east of the Rockies tomorrow (Friday).
The approach of the upper trough will encourage surface low
development over the northern Plains, with appreciable low-level
moisture return expected across the Plains and MS Valley. Given
limited forcing for ascent east of the Rockies, thunderstorm
development should be limited to the warm front over the Upper MS
Valley, and along the Gulf Coast with low-level moisture pivoting
around a surface high along the East Coast. West of the Rockies
though, where upper support is present, cooler temperatures aloft
will promote enough buoyancy to support scattered thunderstorm
development. Given stronger flow aloft and associated vertical wind
shear, some storms could become strong and sustained.
...Portions of the Northern Rockies to the Four Corners...
Scattered thunderstorms will develop by afternoon ahead of the upper
trough, once a well-mixed boundary layer, extending over 600 mb,
becomes established. Temperatures will warm into the 70s F, beneath
7-8 C/km lapse rates, resulting in a few hundred J/kg MLCAPE. This
buoyancy will be constrained to thin profiles, which may limit the
severe threat to some degree. Nonetheless, a 50-70 kt 500 mb jet
streak will impinge on the Northern Rockies to Four Corners regions,
resulting in elongated and modestly curved hodographs. High-based,
fast-moving multicells are the expected mode of convection, with
strong wind gusts likely. A few severe gusts may occur, along with
an instance or two of hail, warranting Category 1/Marginal risk
probabilities across the northern Rockies to the Four Corners.
..Squitieri.. 10/02/2025
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SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0235 PM CDT Thu Oct 02 2025
Valid 041200Z - 051200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE NORTHERN PLAINS...
...SUMMARY...
Strong thunderstorms may impact a corridor across parts of the
northern Great Plains late Saturday afternoon or evening,
accompanied by at least some risk for severe wind and hail.
...Synopsis...
A broad mid-level trough will become established across the Rockies,
with upper ridging expected along the East Coast on Saturday. A
pronounced mid-level impulse will eject into the northern Plains,
supporting rapid surface low deepening over the Dakotas by
afternoon. Seasonal low-level moisture return beneath cooler
temperatures aloft, in tandem with favorable vertical wind shear,
will support scattered strong thunderstorms across the northern
Plains Saturday evening, at least a few of which may be severe.
...Northern Plains...
A surface low will become established across the Dakotas during the
afternoon, with a cold front draped across the central/northern High
Plains. Ahead of the cold front, surface temperatures should reach
the 80s F amid low 60s F dewpoints by afternoon peak heating.
1000-2000 J/kg MLCAPE (locally higher in some spots) is expected
given 7.5-8.5 C/km mid-level lapse rates overspreading the northern
Plains. Modest to substantial convective inhibition will likely
inhibit thunderstorm development over the warm sector through much
of the day. As such, thunderstorms will develop along and perhaps
behind an eastward advancing surface cold front by sunset, when the
primary mid-level impulse ejects from the Rockies. As this occurs,
substantial veering and strengthening of the vertical wind profile
is expected, with 50+ kt southwesterly 500 mb flow overspreading a
30-50 kt southerly low-level jet. 50 kts of effective bulk shear,
mainly parallel to the cold front, will support linear convection,
with at least isolated severe gusts possible. An instance or two of
severe hail may accompany any more discrete storms that manage to
develop.
..Squitieri.. 10/02/2025
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