SPC Jun 6, 2026 1300 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1300Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0700 AM CDT Sat Jun 06 2026

Valid 061300Z - 071200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING FROM INDIANA INTO THE UPPER OHIO VALLEY AND SOUTHERN NEW
ENGLAND...AND OVER PARTS OF EASTERN MONTANA AND WESTERN NORTH
DAKOTA...

...SUMMARY...
Thunderstorms with damaging wind gusts and isolated large hail are
expected to develop later today from parts of the lower Great Lakes
and Ohio Valley into southern New England. Large hail and severe
wind gusts are also expected in the northern High Plains and
southern Plains.

...Indiana to Southern New England...
Morning water vapor loop shows a deepening upper trough over the
Great Lakes region. This trough and an associated mid-level speed
max will spread across the upper Ohio Valley into New England this
afternoon and tonight. Strengthening large-scale ascent ahead of
the trough has led to multiple clusters of ongoing thunderstorms
from eastern IL into parts of OH/PA/NY. One or more of these
clusters, along with new development by early afternoon, is expected
to intensify and spread across the SLGT risk region. Forecast
soundings suggest sufficient CAPE and low-level lapse rates to
support a risk of damaging wind gusts with this activity. Overnight
CAM solutions continue to vary on the likely corridor of greatest
concern. However, there is the potential for a rather widespread
damaging wind event across parts of PA/NY/NJ this afternoon/evening
if sufficient heating and mesoscale organization of the clusters
occur.

...Northern High Plains...
A large upper ridge is in place today over the High Plains region.
A southerly low-level jet is expected to intensify by early evening
as an upper trough approaches and low-level cyclogenesis occurs over
southeast MT. This should encourage the development of evening
thunderstorms across eastern MT tracking into western ND overnight.
It is unclear whether the bulk of these storms will be just west of
the warm sector and elevated, or will be surface-based. Regardless,
large hail is the primary concern.

...Southern Plains...
A weak upper low is tracking northeastward from west TX into
Oklahoma this morning. A band of stronger winds aloft to the east of
the low, coupled with pockets of daytime heating and ample moisture,
will promote damaging wind gusts and hail in the strongest storms.

..Hart/Wendt.. 06/06/2026


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SPC Jun 6, 2026 0600 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1259 AM CDT Sat Jun 06 2026

Valid 061200Z - 071200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE LOWER GREAT LAKES...OHIO VALLEY AND NORTHEAST...

...SUMMARY...
Thunderstorms with severe wind gusts and isolated large hail are
expected to develop today from parts of the lower Great Lakes and
Ohio Valley into the Northeast. Large hail and severe wind gusts are
also expected in the northern High Plains. Strong wind gusts and
hail may also occur in parts of the southern Plains.

...Lower Great Lakes/Ohio Valley/Northeast...
An upper-level trough and an associated mid-level jet streak will
move eastward into the lower Great Lakes today. A cold front will
advance southeastward into the lower Great Lakes, with surface
dewpoints ahead of the front in the mid to upper 60s F. An axis of
moderate instability appears likely to develop well ahead of the
front by early to mid afternoon. As this happens, convective
initiation will take place near this axis of instability from
northern Indiana eastward into northern Pennsylvania and
northeastward into southern New York. Convective coverage will
gradually expand, as a broken line segment moves southeastward into
the Ohio Valley and toward the coast of the Mid-Atlantic and New
England.

RAP forecast soundings at 21Z near the instability axis over
northern Ohio and southwestern Pennsylvania have 0-6 km shear near
45 knots, which could support supercell development. Supercells will
be capable of severe wind gusts, hail and an isolated tornado
threat. During the late afternoon, a transition to more linear
development is expected, which should result in an increased
wind-damage threat.

Further east from central Pennsylvania into southern New England,
forecast soundings at 21Z have 0-6 km shear in the 25 to 30 knot
range with 0-3 km lapse rates between 7.5 and 8 C/km. This
environment will support severe storm development. Although an
isolated supercell will be possible, the most likely mode will be
linear, favoring wind-damage as the primary threat. The potential
for severe gusts will be maximized from south-central Pennsylvania
northeastward into far southern New York. The line segment is
expected to reach the Mid-Atlantic and New England Coasts by early
evening.

...Northern High Plains...
West-southwesterly mid-level flow over the northern High Plains will
become more southwesterly during the day, as an upper-level trough
moves through the Pacific Northwest. At the surface, a low will
deepen over the northern High Plains, with a trough located
northeastward into far northeast Montana. As surface temperatures
warm today, moderate instability will develop near the surface
trough. This, combined with increasing low-level convergence, will
result in scattered convective initiation. Multiple storms are
forecast to move northeastward across the northern High Plains
during the late afternoon and early evening.

RAP forecast soundings near the surface trough in far northeast
Montana at 00Z have MLCAPE around 2000 J/kg with 0-6 km shear near
35 knots. Surface-temperature dewpoint spreads are large with low to
mid-level lapse rates in the 8 to 9 C/km range. This should be
favorable for high-based supercells capable of large hail and severe
wind gusts. The severe threat will likely persist into the early to
mid evening.

...Southern Plains...
A mid-level low will move across west Texas today. At the surface, a
moist airmass will be in place over the southern Plains, where
dewpoints will be from the upper 60s into the mid 70s F. This will
result in the development of moderate instability by afternoon. To
the east of the mid-level low, low-level convergence is forecast to
become maximized over parts of west-central Texas and southern
Oklahoma. As a result, scattered thunderstorms are expected to
develop from late afternoon into the evening. The instability
combined with steep low-level lapse rates (exceeding 7 C/km) will
support an isolated threat for severe wind gusts and hail.

..Broyles/Lyons.. 06/06/2026


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SPC Jun 6, 2026 0100 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 0100Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0800 PM CDT Fri Jun 05 2026

Valid 060100Z - 061200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL PLAINS INTO THE MID MISSOURI AND MID MISSISSIPPI
VALLEYS...

...SUMMARY...
Thunderstorms with large hail and severe wind gusts are expected
this evening from parts of the central Plains into the mid Missouri
and mid Mississippi Valleys. Isolated wind gusts and hail will also
be possible in parts of the upper Mississippi Valley and western
Great Lakes.

...Central Plains/Mid Missouri and Mid Mississippi Valleys...
A mid-level shortwave trough is currently evident on water vapor
imagery over the north-central U.S. The southern part of the trough
extends southwestward into the central Plains. Ahead of this
feature, a moist and unstable airmass is in place from southern
Nebraska and northern Missouri northward into much of Iowa, where
surface dewpoints are in the upper 60s and lower 70s F. Along the
moist axis, the RAP currently has a pocket of strong instability
centered over the mid Missouri Valley with MLCAPE in the 3000 to
4500 J/kg range. A front, where low-level convergence is maximized,
is evident on surface analysis from northwest Iowa southwestward
into south-central Nebraska. Thunderstorms have recently developed
near the front in southeast Nebraska. These storms are expected to
steadily increase in coverage this evening as the shortwave trough
approaches.

From southeast Nebraska into southern Iowa early this evening, RAP
forecast soundings have 0-6 km shear in the 25 to 35 knot range with
700-500 mb lapse rates around 7 C/km. This environment will support
supercells with large hail. Hailstones greater than 2 inches in
diameter will be possible with the more dominant supercells...see
MCD 992. Short-term model forecasts suggest that a cluster of strong
to severe storms will organize during the evening. As this occurs,
the wind-damage threat will likely increase. If a line segment can
become intense, then wind gusts above 70 mph will be possible. The
severe threat will gradually develop eastward across southern Iowa
into northern Illinois from mid to late evening. An isolated severe
threat may persist into the early overnight period.

...Upper Mississippi Valley/Western Great Lakes...
A surface low is evident on surface analysis over northeast
Wisconsin with a cold front extending southwestward across central
and western Wisconsin. A line of strong thunderstorms is ongoing
along the front. Ahead of the front, surface dewpoints in the mid to
upper 60s F are contributing to moderate instability, with the RAP
showing MLCAPE in the 1000 to 2500 J/kg range. Ahead of the front,
the Green Bay and La Crosse WSR-88D VWPs have 0-6 km shear in the 25
to 35 knot range suggesting that deep-layer shear is strong enough
for an isolated severe threat. The more organized multicells along
the line could have potential for hail and isolated severe gusts for
a couple more hours this evening.

..Broyles.. 06/06/2026


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SPC Jun 5, 2026 1630 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1630Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1129 AM CDT Fri Jun 05 2026

Valid 051630Z - 061200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING FROM NEBRASKA/KANSAS INTO NORTHERN ILLINOIS...AND FROM
CENTRAL MINNESOTA INTO CENTRAL WISCONSIN...

...SUMMARY...
Thunderstorms with large hail and severe wind gusts are expected to
develop late this afternoon and evening from parts of the central
Plains into the mid Missouri and mid Mississippi Valleys. Strong to
severe wind gusts and hail will also be possible in parts of the
upper Mississippi Valley.

...Central Plains into the Mid MS Valley...
Morning surface analysis places a low over northwest KS, near the
intersection of weak lee troughing and the western edge of a remnant
outflow boundary extending across southern NE. Upper 60s/low 70s
dewpoints are already in place east/southeast of this surface low
and outflow boundary. Southerly/southeasterly flow will persist
throughout the day, maintaining a large fetch of low-level moisture
advection from the southern Plains into the Mid MS Valley. Steeper
mid-level lapse rates are also emerging out of the central High
Plains, spreading gradually eastward over these moist low-levels
throughout the day. As a result, a corridor of strong to very strong
buoyancy is anticipated from south-central NE/north-central KS along
the IA/MO border into far west-central IL by the late afternoon.

Expectation is that the outflow boundary will gradually retreat
northward while the cold front progresses slowly southeastward
across SD and NE. Convective initiation is anticipated along both of
these boundaries, beginning over north-central KS/south-central NE
near the surface low at the outflow boundary/cold front
intersection. Most guidance indicates this initiation will occur
after 00Z, but earlier initiation appears possible given moist
low-levels, robust heating, and mesoscale convergence. Recent RAP
soundings indicate minimal convective initiation by 21Z.

Once initiation occurs, strong buoyancy (i.e. MLCAPE over 2500 J/kg)
will support intense updrafts capable of large to isolated very
large hail. Modest deep-layer shear (i.e. effective bulk shear less
than 30 kt) could limit storm organization, with a trend towards a
more outflow-dominant mode. The generally modest mid-level flow also
suggests upscale growth into an organized convective line is low.
Even so, a combination of convergence along the outflow and/or cold
front, as well as modest warm-air advection, will contribute to
additional storm development eastward into the Mid MS Valley.

...Upper Midwest...
Recent surface analysis shows a cold front extending from
north-central WI southwestward through central SD. A low exists
along this boundary near the ND/SD/WI border intersection. This low
is forecast to track eastward along the front as it gradually shifts
southeastward, moving in tandem with a shortwave trough moving
through the northern Plains into the Upper Midwest. Buoyancy will be
more limited here than areas farther south, but still sufficient for
a few stronger, more organized storms, particularly since the
deep-layer vertical shear will be stronger. Discrete storms with
large hail as the primary risk are possible early in the convective
cycle. Thereafter, a trend towards more bowing segments with
damaging gusts is expected. Multiple rounds of storms are possible,
and the overall coverage is expected to be high enough to merit
introducing 15% hail and wind probabilities.

...Lower MI...
An MCV (associated with an overnight MCS) is moving across northern
IL/far southern WI this morning. Activity associated with this MCV
is currently weak and non-severe, but potential for
re-intensification exists this afternoon as activity moves into
northern IN and southern lower MI. Cloud cover introduces some
uncertainty regarding daytime heating and resultant buoyancy.
However, if sufficient daytime heating can occur, steep lapse rates
and mesoscale organization of the MCS could result in sporadic
damaging winds.

..Mosier/Chalmers.. 06/05/2026


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