RSS Mesoscale Discussions from Storm Prediction Center
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1101 AM CDT Sat Jul 04 2026
Valid 041630Z - 051200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE MID-ATLANTIC AS WELL AS ACROSS PORTIONS OF SOUTHERN KANSAS
AND NORTHERN OKLAHOMA...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL
PLAINS INTO THE MID ATLANTIC AND SOUTHERN NEW ENGLAND...
...SUMMARY...
Clusters of storms will move across parts of the Allegheny Plateau
into the Mid-Atlantic, with potential for numerous damaging wind
gusts. Additional severe thunderstorms are expected across the Great
Plains this afternoon and evening, posing a risk for severe wind
gusts and large hail.
...Mid Atlantic...
A hot summer day is forecast across the Mid Atlantic region today
with temperatures well into the 90s and dewpoints ranging from the
mid 60-lower 70s F. Full sun will result in steep low-level lapse
rates and high CAPE values beneath moderately strong northwest
mid-level flow. Scattered thunderstorms are expected to develop
along/east of the Blue Ridge and spread eastward across parts of
PA/VA/NJ/DE through the late afternoon and evening. Parameters
remain favorable for downburst winds in these clusters of storms.
...PA/NY into southern New England...
A weak shortwave trough and associated mid level speed max is
rotating southeastward out of Ontario/Quebec into the northeast US.
Ample low-level moisture and pockets of moderate CAPE will result in
widely scattered afternoon thunderstorm development from northern PA
into central NY. These storms will spread southeastward into
southern New England by early evening. The strongest cells will
pose a risk of damaging wind gusts.
..IL/IN...
A remnant MCV from overnight convection is analyzed over eastern IA,
with a surface boundary extending eastward just south of CHI. The
air mass to the south of the boundary across IL will become very
unstable by mid-afternoon, leading to scattered thunderstorms.
Favorable thermodynamic parameters suggest a risk of damaging winds
as these storms organize and track into IN by evening.
...KS/MO...
An ongoing cluster of strong/severe storms is affecting eastern KS.
Given the moist and unstable air mass to the east and sufficient
mesoscale organization, it is probable that this cluster will
persist into the afternoon. Storms will track into western MO with
a continued risk of locally damaging wind gusts.
...KS/OK/AR...
In the wake of the aforementioned cluster of storms, new development
is likely later this afternoon along the remnant outflow boundary
across southern KS and northern OK. High CAPE values to the south
of the boundary will promote the ENH risk of damaging winds and some
hail as storms build southeastward across central/eastern OK and
into western AR this evening.
...TX Panhandle...
A weak surface boundary will be the focus for scattered late
afternoon thunderstorms over the southern/eastern TX Panhandle. The
strongest cells may produce damaging wind gusts and large hail for a
few hours.
...Northeast CO...
Southerly low level winds will maintain dewpoints in at least the
40s over parts of eastern CO this afternoon despite strong
heating/mixing. This will be sufficient to allow scattered
thunderstorms to form along the foothills and DCVZ. A few severe
cells are possible with large hail being the main risk.
...MN/SD...
Similar to yesterday, a few afternoon and early evening
thunderstorms are expected to develop ahead of a weak shortwave
trough. The strongest cells might produce large hail or gusty
winds.
..Hart/Weinman.. 07/04/2026
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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0248 PM CDT Sat Jul 04 2026
Valid 042000Z - 051200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE SOUTHERN PLAINS AND MID ATLANTIC...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
THE CENTRAL HIGH PLAINS AND FROM THE SOUTHERN HIGH PLAINS TO
SOUTHERN NEW ENGLAND...
...SUMMARY...
Clusters of storms will continue to move across parts of the
Allegheny Plateau into the Mid-Atlantic, with potential for numerous
damaging wind gusts. Additional severe thunderstorms are still
expected across the Great Plains this afternoon and evening, posing
a risk for severe wind gusts and large hail.
...20Z Update...
A cold-pool-driven MCS, with a history of measured 50+ kt gusts and
wind damage, continues to rapidly propagate eastward across central
MO. While deep-layer shear is quite modest over the Ozarks, a
pronounced baroclinic boundary is draped across central MO into the
St. Louis Metropolitan area. The MCS has likely maintained its
intensity thus far by riding this boundary and ingesting some
vorticity for bookend vortex and rear-inflow jet maintenance. It is
unclear how long this MCS will remain strong/organized given the
lack of ambient deep-layer shear. However. surface temperatures on
the warm side of the boundary exceeding 90 F, amid mid 70s F
dewpoints, is yielding a gradient of 2500-4500 J/kg SBCAPE, which
should support some severe gust threat for this MCS for at least the
next few hours. As such, 30 percent wind probabilities have been
added ahead of the MCS.
Guidance consensus, including early depictions from WoFS output,
suggests that an MCS will quickly surge southeastward across
portions of the southern Plains after initiating along the KS/OK
border late this afternoon. The farther southeast initiation (given
the current position of the surface outflow boundary left behind
from the previous MCS), and southeastward surging potential, it
appears that the greatest wind threat will exist into east-central
OK. 30 percent/CIG1 wind probabilities have been extended into this
region.
Five percent hail probabilities have been added across portions of
the lower Hudson Valley. Here, MRMS mosaic MESH data suggests that
marginally severe hail may already be falling with the more robust
storms over northern PA. Furthermore, stronger mid-level flow is
grazing the lower Hudson Valley, contributing to 30-40 kts of
effective bulk shear amid 1000+ J/kg MLCAPE, which should be
adequate to support a continued hail threat.
Otherwise, the previous forecast remains on track, including the
potential for numerous damaging to occasionally severe gusts
expected across portions of the Mid Atlantic into southern New
England through the afternoon and evening hours. Mostly minor
adjustments have been made to the remainder of the outlook to
account for guidance consensus and observations.
..Squitieri.. 07/04/2026
.PREV DISCUSSION... /ISSUED 1101 AM CDT Sat Jul 04 2026/
...Mid Atlantic...
A hot summer day is forecast across the Mid Atlantic region today
with temperatures well into the 90s and dewpoints ranging from the
mid 60-lower 70s F. Full sun will result in steep low-level lapse
rates and high CAPE values beneath moderately strong northwest
mid-level flow. Scattered thunderstorms are expected to develop
along/east of the Blue Ridge and spread eastward across parts of
PA/VA/NJ/DE through the late afternoon and evening. Parameters
remain favorable for downburst winds in these clusters of storms.
...PA/NY into southern New England...
A weak shortwave trough and associated mid level speed max is
rotating southeastward out of Ontario/Quebec into the northeast US.
Ample low-level moisture and pockets of moderate CAPE will result in
widely scattered afternoon thunderstorm development from northern PA
into central NY. These storms will spread southeastward into
southern New England by early evening. The strongest cells will
pose a risk of damaging wind gusts.
..IL/IN...
A remnant MCV from overnight convection is analyzed over eastern IA,
with a surface boundary extending eastward just south of CHI. The
air mass to the south of the boundary across IL will become very
unstable by mid-afternoon, leading to scattered thunderstorms.
Favorable thermodynamic parameters suggest a risk of damaging winds
as these storms organize and track into IN by evening.
...KS/MO...
An ongoing cluster of strong/severe storms is affecting eastern KS.
Given the moist and unstable air mass to the east and sufficient
mesoscale organization, it is probable that this cluster will
persist into the afternoon. Storms will track into western MO with
a continued risk of locally damaging wind gusts.
...KS/OK/AR...
In the wake of the aforementioned cluster of storms, new development
is likely later this afternoon along the remnant outflow boundary
across southern KS and northern OK. High CAPE values to the south
of the boundary will promote the ENH risk of damaging winds and some
hail as storms build southeastward across central/eastern OK and
into western AR this evening.
...TX Panhandle...
A weak surface boundary will be the focus for scattered late
afternoon thunderstorms over the southern/eastern TX Panhandle. The
strongest cells may produce damaging wind gusts and large hail for a
few hours.
...Northeast CO...
Southerly low level winds will maintain dewpoints in at least the
40s over parts of eastern CO this afternoon despite strong
heating/mixing. This will be sufficient to allow scattered
thunderstorms to form along the foothills and DCVZ. A few severe
cells are possible with large hail being the main risk.
...MN/SD...
Similar to yesterday, a few afternoon and early evening
thunderstorms are expected to develop ahead of a weak shortwave
trough. The strongest cells might produce large hail or gusty
winds.
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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1203 PM CDT Sat Jul 04 2026
Valid 051200Z - 061200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
MID-ATLANTIC SUNDAY AFTERNOON AND EVENING...
...SUMMARY...
Scattered wind damage is possible with thunderstorms across the
Mid-Atlantic Sunday afternoon and evening. Isolated strong storms
also are possible across Montana and western North Dakota, and
portions of the southern Plains to the Tennessee Valley.
...Mid-Atlantic...
A weak surface low is forecast to move west to east along a sagging
cold front/baroclinic zone draped across PA into northern
NJ/southeast NY on Sunday/Sunday evening. Meanwhile, lee troughing
will develop across VA. A hot and very moist airmass will reside
near and south of these boundaries, which will serve as a focus for
severe storm development during the afternoon and into evening.
Southwesterly flow aloft will weaken through the day as an upper
shortwave impulse lifts northeast of the region, but around 20-30 kt
mid/upper-level flow will persist. Moderate to strong
destabilization is expected and thunderstorm clusters are expected
by early to mid-afternoon. Sufficient clustering could occur along
the southward-sagging cold front and one or more forward propagating
clusters will be possible from northern VA into southeast PA until
storms move offshore the Mid-Atlantic coast during the evening.
Sufficient consistency among deterministic/CAMs and AI/ML guidance
exists regarding storm coverage to warrant an upgrade to 30 percent
wind probabilities for portions of the region.
...Southern Plains to TN Valley...
An remnant/weakening MCS is expected to be located over OK or AR
Sunday morning. An MCV related to this feature will progress
eastward toward the Lower MS and TN Valley vicinity through the day.
Further south and west near the Red River Valley/North Texas into
the southern High Plains, outflow associated with the late-Day
1/Saturday into early Day 2/Sunday MCS may arc across this region.
Differential heating could occur along this boundary, providing
support for redevelopment during the afternoon/evening. Boundary
layer moisture will be modest with westward extent into the High
Plains, but steep lapse rates aloft, and increasing moisture with
eastward extent into the Lower MS Valley will support a corridor of
moderate instability in the vicinity of the surface boundary.
Northwesterly flow aloft will also modestly strengthen through the
day, fostering weak, but perhaps sufficient vertical shear for
transient organized cells/clusters along the boundary.
Further east, the MCV will locally enhance vertical shear amid a
very moist and moderately unstable airmass. This could foster
potential for one or more forward propagating storm clusters, and
some risk for damaging gusts from wet microbursts, leading to a
broad expansion of the Marginal (level 1 of 5) risk across parts of
the Lower MS/TN Valley vicinity.
...Northern Rockies into North Dakota...
West/southwest flow aloft will strengthen across MT into ND as an
upper shortwave trough moving across western Canada glances northern
portions of the U.S. A plume of steep midlevel lapse rates will
stretch from the northern Great Basin through southern/eastern MT
into the western Dakotas. Low-level moisture will not be impressive,
but the steep lapse rates aloft will support a corridor of modest
destabilization across MT, and somewhat greater across western ND
where boundary-layer moisture will be marginally better along a
surface trough. Vertically veering wind profiles, with increasing
speeds above 700 mb will support effective shear magnitudes greater
than 30 kt, and organized storms are possible. Strong gusts and
isolated hail will be the main hazards with these storms during the
afternoon into evening.
..Leitman.. 07/04/2026
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SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0155 PM CDT Sat Jul 04 2026
Valid 061200Z - 071200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN PLAINS INTO MINNESOTA...AND THE SOUTHERN
MID-ATLANTIC...
...SUMMARY...
Strong to severe thunderstorms are possible Monday afternoon and
evening across portions of the southern Mid-Atlantic and the
northern Plains.
...VA/NC vicinity...
Upper troughing over the Midwest will continue to slowly shift east
toward the Appalachians on Monday. Modest deep-layer southwesterly
flow will overspread the central Appalachians to the Mid-Atlantic
vicinity as a surface low develops in the vicinity of WV. A surface
boundary/cold front will sag southward across PA while surface
troughing develops in the lee of the VA/NC mountains. A very moist
airmass will persist and moderate destabilization is forecast.
Thunderstorm clusters will once again develop and pose a risk for
sporadic wind damage Monday afternoon into early evening.
...Northern Plains into northwest MN...
An upper shortwave trough will move east across the Canadian
Prairies, glancing the U.S. northern Plains vicinity. This will
bring a band of enhance mid/upper westerly flow across the region
while a surface cold front develops southeast through the afternoon
and nighttime hours. Southerly low-level flow will transport 60s
dewpoints northward ahead of the front beneath modestly steep
midlevel lapse rates. This will support moderate to strong
destabilization. It is uncertain how far south convection may
develop as large-scale ascent weakens into South Dakota and capping
increases. However, supercell wind profiles are evident in forecast
soundings, and where storms do develop, an accompanying risk for
severe gusts and large hail is possible. An upgrade to Slight risk
(level 2 of 5) may be needed in subsequent outlooks if confidence in
storm coverage increases.
..Leitman.. 07/04/2026
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