ACUS48 KWNS 100849
SWOD48
SPC AC 100848

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0348 AM CDT Tue Jun 10 2025

Valid 131200Z - 181200Z

...DISCUSSION...
Models are in good agreement with the overall pattern through about
Sunday/D6, depicting upper ridging over the northern Plains and
rising heights across the Northeast and general troughiness over the
Northwest. During that same period, the disturbance over the
southern Plains is forecast to lift toward the mid MS Valley with
weakening trend.

The greatest risk of severe storms will generally stretch from the
northern Rockies into the northern Plains, as weak but backed
low-level winds maintain a moist plume out of the central Plains and
into MT and the Dakotas.

On Friday/D4, scattered strong storms may occur over central MT,
beneath modest southwest winds aloft and with around 1000 J/kg
MUCAPE. Instability will build further in the Saturday/D5 to
Sunday/D6 time frame, with greater storm coverage expected. However,
winds aloft will be marginal. Still, developing west to northwest
flow aloft could eventually result in an MCS pattern with attendant
wind potential. Predictability is low at this time, but the northern
and central Plains region will be monitored over the next several
days for potential categorical risk outlines.

..Jewell.. 06/10/2025

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

ACUS48 KWNS 110839
SWOD48
SPC AC 110838

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0338 AM CDT Wed Jun 11 2025

Valid 141200Z - 191200Z

...DISCUSSION...
For Saturday/D4 into Sunday/D5, moderate southwest flow aloft will
remain over the Pacific Northwest and toward the northern Rockies,
with a gradual flattening of the upper ridge over the northern
Plains. Then through Wednesday/D8, modest west/northwest flow aloft
is likely to persist over the High Plains. Models diverge greatly
after this time frame. However, this pattern will generally favor
daily thunderstorms along the length of the High Plains, from MT
into eastern NM during the afternoon, and persisting into parts of
the Great Plains during the evenings.

The primary driver of severe potential will be a large area of
moderate to strong instability with 2000-3000+ J/kg MUCAPE
developing daily. As storms move off the higher terrain, corridors
of wind damage may materialize. Predictability is low this far out,
but categorical risk upgrades appear likely as these periods get
closer in time. The primary risk appears to be damaging winds, but
sporadic large hail is possible with the late afternoon activity.

..Jewell.. 06/11/2025

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

ACUS48 KWNS 120835
SWOD48
SPC AC 120833

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0333 AM CDT Thu Jun 12 2025

Valid 151200Z - 201200Z

...DISCUSSION...
During the Sunday/D4 to Monday/D5 period, an upper ridge is forecast
to remain over the Plains, with modest southwest flow aloft over the
West. Models suggest that around Tuesday/D6, the upper ridge will
break down over the central/northern Plains, although the amplitude
and track of the wave is in question. Ample low-level moisture will
be in place from the Plains to the East Coast, with mid to upper 60s
F as far north as southern parts of the Great Lakes.

As a result of this large area of moisture and instability, widely
scattered thunderstorms will be common each day. The northern Plains
appears to have the greatest change of organized severe storms
includes MCS/s, but predictability is clearly low at this time with
the uncertain wave. However, it appears that the Tuesday/D6 to
Wednesday/D7 time frame may yield a corridor of organized damaging
wind potential over parts of the northern and central plains to
Midwest, and these trends will continue to be monitored.

..Jewell.. 06/12/2025

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

ACUS48 KWNS 130901
SWOD48
SPC AC 130859

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0359 AM CDT Fri Jun 13 2025

Valid 161200Z - 211200Z

...DISCUSSION...
...Monday/Day 4 to Wednesday/Day 6...
A mid-level ridge across the Great Plains is forecast to become less
amplified on Monday, as multiple shortwave troughs move through
westerly flow across the north-central states. A moist airmass is
forecast across much of the central and northern Plains, where
moderate to strong instability appears likely to develop by
afternoon. Along the northern edge of the stronger instability,
scattered convective initiation is expected. The instability,
combined with moderate deep-layer shear, should support a severe
threat. Large hail and severe wind gusts will be possible during the
afternoon and evening.

The mid-level ridge is forecast to move eastward into the Missouri
Valley on Tuesday, as a trough moves into the Rockies. At the
surface, a moist airmass is forecast from the central Plains into
the Missouri Valley, where moderate to strong instability appears
likely to develop by afternoon. Large-scale ascent ahead of the
approaching trough is forecast to move into the central Plains
Tuesday evening. As a result, a large area of thunderstorms is
forecast to develop from northern Kansas into much of Nebraska.
Model forecasts suggest that moderate deep-layer shear will be in
place, which would support a large hail and wind-damage threat.

The mid-level trough is forecast to move across the Great Plains on
Wednesday. A moist airmass is forecast to remain in place to the
east of the trough across the lower Missouri and Mississippi
Valleys. Ahead of the trough, moderate instability is forecast by
afternoon. Thunderstorm development is expected with this unstable
airmass from eastern Kansas northeastward into the mid to upper
Mississippi Valley. A severe threat will be possible. The greatest
potential for severe storms could be from northern Missouri into
southern Wisconsin, along and near the axis of a low-level jet.

...Thursday/Day 7 and Friday/Day 8...
From Thursday into Friday, the mid-level trough, and an associated
cold front, is forecast to move from the mid Mississippi Valley to
the Eastern Seaboard. A moist and unstable airmass should be in
place ahead of the trough. Thunderstorm development will be possible
along parts of the front, and across the warm sector. Although a
severe threat may develop as instability increases during the day,
the timing of the front remains questionable and predictability is
low.

..Broyles.. 06/13/2025

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

ACUS48 KWNS 140900
SWOD48
SPC AC 140859

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0359 AM CDT Sat Jun 14 2025

Valid 171200Z - 221200Z

...DISCUSSION...
...Tuesday/Day 4 and Wednesday/Day 5...
A mid-level trough is forecast to move into the High Plains on
Tuesday, as a cold front moves southward into the central Plains.
Ahead of the front, a moist and unstable airmass is forecast by
afternoon from Kansas and southeastern Nebraska into northern
Missouri. As surface temperatures warm during the day, thunderstorm
development will likely take place along parts of the front.
Moderate deep-layer shear is forecast across much of the region,
suggesting that storms should become organized. Supercells and short
intense line segments will be possible, with large hail and wind
damage as the primary threats.

The mid-level trough is forecast to move eastward through the
central states on Wednesday, as a cold front advances southeastward
into the lower Missouri Valley and western Great Lakes. Ahead of the
front, an axis of moderate instability is forecast to be in place by
afternoon. Thunderstorm development will be likely along parts of
the front. Moderate deep-layer shear is forecast along and near much
of the instability axis, suggesting that a severe threat will again
be possible during the afternoon and evening.

...Thursday/Day 6 to Saturday/Day 8...
The mid-level trough is forecast to move eastward into the Northeast
on Thursday. Ahead of the trough and its associated cold front,
moderate instability is expected to develop by afternoon.
Thunderstorm development will be most likely from parts of southern
New England southwestward into the Mid-Atlantic. Deep-layer shear
should be sufficient for an isolated severe threat. However, there
is considerable uncertainty due to the issues of frontal timing and
instability magnitude.

From Friday into Saturday, a mid-level ridge is forecast to move
eastward from the northern Plains into the Great Lakes. Although a
moist and unstable airmass will likely be in place across the
north-central U.S., large scale ascent should be weak across most of
the region. For this reason, predictability is low concerning any
potential severe threat.

..Broyles.. 06/14/2025

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

ACUS48 KWNS 150900
SWOD48
SPC AC 150859

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0359 AM CDT Sun Jun 15 2025

Valid 181200Z - 231200Z

...DISCUSSION...
...Wednesday/Day 4 and Thursday/Day 5...
A mid-level trough is forecast to move through the Upper Midwest on
Wednesday, as a cold front advances southeastward into the lower
Missouri and mid-Mississippi Valleys. Ahead of the front, moderate
instability is forecast to develop by afternoon. Thunderstorms
appear likely to form along parts of the front, with several
clusters or line segments moving eastward toward the instability
axis during the late afternoon and early evening. Moderate
deep-layer shear should support severe storms with large hail and
wind damage as the primary threats.

The mid-level trough is forecast to move into the lower Great Lakes
and upper Ohio Valley on Thursday, as the cold front advances into
the central Appalachians. As the airmass ahead of the front
destabilizes, scattered thunderstorms are expected to form along and
ahead of the front. The models suggest that moderate deep-layer
shear will be in place across much of the northeastern U.S., which
will likely support organized storms. Damaging winds gusts will be
the most likely severe threat.

...Friday/Day 6 to Sunday/Day 8...
A shortwave mid-level ridge is forecast to move into the upper
Mississippi Valley on Friday. The ridge is forecast to remain over
the region on Saturday as mid-level heights rise. Beneath the ridge,
a moist and unstable airmass will likely be in place from the lower
to mid Missouri Valley northeastward into the western Great Lakes.
Within this airmass, isolated thunderstorm development should take
place both Friday and Saturday afternoon. Instability and deep-layer
shear appear sufficient for a localized severe threat. However, the
presence of the ridge introduces uncertainty as to where the
greatest potential for convection will be. For this reason,
predictability is low.

On Sunday, a mid-level trough is forecast to develop over the
Rockies as a ridge moves into the Great Lakes region. Although a
moist and unstable airmass should be located over parts of the
northern and eastern U.S., large-scale ascent and mid-level flow is
forecast to be relatively weak in most areas. For this reason, any
severe potential is expected to remain isolated.

..Broyles.. 06/15/2025

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

ACUS48 KWNS 160857
SWOD48
SPC AC 160855

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0355 AM CDT Mon Jun 16 2025

Valid 191200Z - 241200Z

...DISCUSSION...
...Thursday/Day 4 and Friday/Day 5...
A mid-level trough is forecast to move into the Northeast on
Thursday, as a cold front advances eastward into the central
Appalachians. Ahead of the front, a moist airmass will be in place.
Moderate instability is expected to develop ahead of the front
across the Carolinas and Mid-Atlantic. As surface temperatures warm
during the day, scattered convective initiation will likely take
place along and ahead of the front. Moderate deep-layer shear and
steep low-level lapse rates should support a severe threat during
the afternoon, with the primary threat being damaging wind gusts.

On Friday, a mid-level ridge is forecast to move eastward across the
northern Plains. Beneath the ridge, a moist airmass will likely be
in place, and moderate instability is expected to develop within
this airmass. Ahead of the ridge, thunderstorm development will be
possible in the upper Mississippi Valley during the afternoon.
Although a severe threat may develop in areas that become moderately
unstable, there is some uncertainty concerning convective coverage
due to the presence of the ridge.

...Saturday/Day 6 to Monday/Day 8...
Mid-level heights are forecast to rise on Saturday and Sunday across
the eastern half of the nation, as a large area of high pressure
dominates. In the western U.S. over the weekend, a mid-level trough
is forecast to move northeastward from the Intermountain West into
the northern High Plains. Ahead of the trough, strong to severe
thunderstorms will be possible Saturday afternoon and evening across
parts of eastern Montana. In spite of the potential, there is still
spatial uncertainty concerning the timing of the trough. The severe
threat is expected to shift northeastward into Canada on Sunday.

On Monday, southwest mid-level flow is forecast over much of the
north-central U.S. Isolated to scattered thunderstorms will be
possible over parts of the northern Plains and upper Mississippi
Valley. An isolated severe threat will again be possible, but there
is considerable uncertainty on any potential scenario.

..Broyles.. 06/16/2025

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

ACUS48 KWNS 170903
SWOD48
SPC AC 170901

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0401 AM CDT Tue Jun 17 2025

Valid 201200Z - 251200Z

...DISCUSSION...
...D4/Friday...
A surface cyclone is forecast to deepen over the northern/central
High Plains on Friday, as a mid/upper-level trough shifts gradually
eastward across the western CONUS. Strong to extreme buoyancy will
develop by afternoon across parts of the central/northern Plains,
along/south of an effective warm front that will extend east of the
surface low. Much of the warm sector will likely remain capped, but
isolated storm development will be possible by late afternoon
near/north of the warm front, with increasing storm coverage during
the evening in response to a strengthening low-level jet. Supercells
will be possible initially, though the pattern suggests potential
for an MCS to develop and move eastward Friday night across the
upper Great Lakes vicinity.

Guidance continues to vary substantially regarding the most favored
corridor for an organized severe threat. For example, the GFS/GEFS
is farther north across ND/northern MN, while the ECMWF/ECENS is
farther south across central MN/northern WI. Severe probabilities
will eventually be needed for this scenario, but confidence is the
favored corridor is too low for a 15% area.

Strong to severe storms may also develop across the northern Rockies
and spread eastward across MT, in association with the approaching mid/upper-level trough. Probabilities will likely be needed for this
scenario in future outlooks, though confidence is too low for a 15%
area at this time.

...D5/Saturday...
A similar surface pattern is expected over the Great Plains and
upper Midwest on Saturday compared to D4/Friday. However, an
amplifying upper ridge may tend to suppress storm development
through much of the period. Some severe potential may again evolve
across MT along the northwest periphery of the ridge. There may also
be some potential for strong to severe storms along the northeast
periphery of the ridge into parts of the lower Great Lakes and New
England.

...D6/Sunday - D8/Tuesday...
An upper-level ridge will remain prominent through the weekend into
early next week across parts of the central/eastern CONUS. Strong to
severe storms and possible MCS development could continue to occur
along the periphery of the ridge, but predictability becomes quite
low at this range regarding the details of any organized threat.

..Dean.. 06/17/2025

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

ACUS48 KWNS 180843
SWOD48
SPC AC 180842

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0342 AM CDT Wed Jun 18 2025

Valid 211200Z - 261200Z

...DISCUSSION...
...D4/Saturday...
An amplified upper-level pattern will continue into Saturday, with a
prominent ridge extending from the Southeast into the Midwest and
Ohio Valley, and a deep trough over much of the West. Large to
extreme buoyancy will again develop across parts of the
central/northern Plains and Upper Midwest, but the influence of the
ridge will tend to suppress storm development across the warm
sector.

While differing in the details, some extended-range guidance
suggests that an MCS (or at least its remnant MCV) that develops
late on D3/Friday will move across the far northern Great Lakes and
adjacent parts of Ontario on Saturday, and potentially into parts of
the lower Great Lakes by Saturday evening. Should such an evolution
occur, some severe threat could accompany this system, but
predictability for such a scenario at this range is inherently low.

Farther west, there is substantial spread in guidance regarding the
magnitude of low-level moisture and instability across parts of MT
and northern WY into western ND on Saturday. However, if stronger
flow associated with the western trough can impinge upon favorable
instability, then an organized severe threat could evolve during the
afternoon and evening.

...D5/Sunday...
The western trough is generally forecast to take on more of a
positive tilt and eventually deamplify on Sunday, as a substantial
shortwave and midlevel jet maximum eject across parts of the
northern High Plains. As this occurs, a cold front will move across
parts of the northern/central Plains. At this time, it appears the
organized severe threat may be limited by very warm temperatures
aloft and a tendency for stronger deep-layer flow to lag behind the
front.

Strong buoyancy may spread into parts of the Ohio Valley and
Northeast on Sunday. Some organized severe potential could develop
within the instability gradient along the periphery of the ridge,
though mesoscale details remain highly uncertain at this time.

...D6/Monday - D8/Wednesday...
Uncertainty increases into early next week regarding evolution of
the synoptic pattern, though guidance generally suggests that an
upper ridge will remain prominent across parts of the eastern CONUS,
while a weak upper trough will persist across parts of the West into
the northern and central Plains. While some severe potential could
evolve across parts of the Great Plains, Great Lakes, and Northeast
along the periphery of the ridge, details regarding favored days and
locations remain highly uncertain.

..Dean.. 06/18/2025

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

ACUS48 KWNS 190847
SWOD48
SPC AC 190845

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0345 AM CDT Thu Jun 19 2025

Valid 221200Z - 271200Z

...DISCUSSION...
...D4/Sunday...
The upper-level trough over the West is forecast to take on more of
a positive tilt on Sunday, as an embedded shortwave and attendant
midlevel jet maximum move across the northern Rockies/High Plains.
As this occurs, a surface low is forecast to move from SD toward the
upper Great Lakes, as a trailing cold front moves through the
northern/central Plains. Guidance varies regarding frontal timing,
though generally agrees that stronger mid/upper-level flow will tend
to lag behind the front.

While details remain uncertain, strong to potentially severe storms
may develop near/north of the surface low across parts of the
Dakotas/MN, and also along the trailing cold front into the central
Plains.

...D5/Monday - D8/Thursday...
The upper ridge across the Southeast is expected to remain in place
through at least early next week, with some guidance suggesting
potential for deamplification by the middle of the week. Multiple
shortwaves may emerge from the persistent (though weakening) western
trough through at least Wednesday, resulting in some potential for
strong to severe storms along the periphery of the upper ridge from
the Plains into the upper Midwest and Great Lakes, and possibly
parts of the Northeast. However, predictability remains quite low
regarding the details of any organized severe threats during this
time frame.

..Dean.. 06/19/2025

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

ACUS48 KWNS 200844
SWOD48
SPC AC 200842

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0342 AM CDT Fri Jun 20 2025

Valid 231200Z - 281200Z

...DISCUSSION...
...D4/Monday...
A mid/upper-level shortwave trough initially over the northern
Plains and upper Midwest is forecast to move into Ontario on Monday,
along the northern periphery of an amplified upper ridge over the
eastern CONUS. A cold front will move through parts of the Great
Lakes, Upper Midwest and central Plains. The strongest deep-layer
flow may tend to lag behind the front, but moderate to strong
instability could support strong to potentially severe storms along
the front during the afternoon and evening.

Farther east, strong instability is generally forecast to develop
across parts of the Mid Atlantic into New England. However, due to
the influence of the upper ridge, there is currently little signal
for diurnal storm development across this region on Monday.

...D5/Tuesday...
Extended-range guidance is in reasonably good agreement that a cold
front will move southward across the lower Great Lakes into New
England on Tuesday. Favorable low-level moisture and strong
instability could support severe-storm potential along the front
during the afternoon and evening. However, coverage of storms is
currently uncertain, due to the lingering influence of the upper
ridge, and a tendency for stronger large-scale ascent to be
displaced well north of the front.

The western upper trough is forecast to deamplify on Tuesday, with
most guidance suggesting that mid/upper-level flow will tend to
weaken downstream across the Great Plains and upper Midwest.
However, strong to locally severe storms could again be possible
near the front, which may begin to move northward across the central
Plains as a warm front through the day.

...D6/Wednesday - D8/Friday...
Predictability begins to wane by the middle of next week regarding
the evolution of synoptic features across the CONUS, though the same
general pattern of a weak upper trough in the West and an upper
ridge over the East may continue through at least Wednesday. In the
absence of any apparent strong forcing mechanisms, organized severe
potential (if any) may tend be focused near a convectively
influenced front across parts of the Plains into the Midwest and
Great Lakes.

..Dean.. 06/20/2025

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

ACUS48 KWNS 210843
SWOD48
SPC AC 210842

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0342 AM CDT Sat Jun 21 2025

Valid 241200Z - 291200Z

...DISCUSSION...
...D4/Tuesday...
Aside from some modest deamplification, little change to the
large-scale pattern is expected on Tuesday. An upper trough will
remain over the western CONUS, while an upper ridge persists over
the East.

Scattered to numerous thunderstorms will again be possible along the
western and northern periphery of the upper ridge, from the
central/southern High Plains into the Upper Midwest. Deep-layer flow
will generally be modest, but some severe threat could evolve in the
vicinity of an outflow-influenced front, in the presence of
favorable low-level moisture and moderate to strong buoyancy.

Farther east, a cold front is forecast to move southward across
parts of northern New England. Guidance varies regarding the extent
to which stronger deep-layer flow and large-scale ascent lag behind
the front, but moderate to strong buoyancy could support at least an
isolated severe threat during the afternoon and evening.

...D5/Wednesday...
Continued modest weakening of both the western trough and eastern
ridge is generally forecast on Wednesday. Scattered to numerous
thunderstorms will again be possible from the High Plains into the
Midwest, Great Lakes, and Northeast, along the periphery of the
ridge. Deep-layer flow is expected to be relatively weak across most
areas, but mesoscale corridors of somewhat greater severe threat
could evolve within this pattern.

...D6/Thursday - D8/Saturday...
Predictability of the large-scale pattern begins to notably decrease
by the end of next week. In general, an upper ridge may persist over
the Southeast, while one or more mid/upper-level shortwave troughs
move across the northern CONUS. This pattern may eventually yield an
increasing threat for organized severe storms across the northern Rockies/Plains and Upper Midwest, but details are very uncertain at
this forecast range.

..Dean.. 06/21/2025

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

ACUS48 KWNS 220834
SWOD48
SPC AC 220832

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0332 AM CDT Sun Jun 22 2025

Valid 251200Z - 301200Z

...DISCUSSION...
...D4/Wednesday...
Extended-range guidance generally indicates that the persistent
upper ridge across the eastern CONUS will begin to dampen on
Wednesday. Multiple low-amplitude midlevel shortwave troughs will
move along the periphery of the upper ridge from the
central/northern High Plains into the Great Lakes. Mid/upper-level
flow will generally be rather weak, but may be locally stronger in
the vicinity of any shortwave troughs.

Some severe threat could develop where pockets of somewhat stronger
flow overlap moderate to strong buoyancy along the periphery of the
ridge. An MCS may develop late on D3/Tuesday and move across parts
of the central Plains and Midwest into at least early Wednesday.
This MCS could persist through the day, with additional development
possible along an outflow-influenced front. Other strong to severe
storms may again develop across parts of the central/northern High
Plains. Confidence regarding the details of any organized severe
threat is too low to delineate a 15% area at this time.

...D5/Thursday - D8/Sunday...
Guidance generally suggests that the persistent upper ridge will
continue to weaken with time, resulting in a more zonal pattern by
the upcoming weekend. Stronger flow may become increasingly confined
to the northern tier of states. This could lead to periodic severe
threats across parts of the northern Plains into the Great Lakes and
Northeast.

One area of interest is across parts of the northern Plains Friday
into Saturday. Some guidance takes a mid/upper-level shortwave
trough from the Pacific Northwest into the northern Great Plains
during this period, where it may impinge upon increasing low-level
moisture and instability, resulting in potential for organized
severe storms.

..Dean.. 06/22/2025

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

ACUS48 KWNS 230901
SWOD48
SPC AC 230859

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0359 AM CDT Mon Jun 23 2025

Valid 261200Z - 011200Z

...DISCUSSION...
...D4/Thursday: Parts of the Midwest/Great Lakes...
An area of interest for severe-storm potential on Thursday resides
from eastern IA/southeast MN into northern IL/southern WI. A
mid/upper-level shortwave trough is generally forecast to move
across parts of the Midwest into the Great Lakes during the
afternoon, potentially accompanied by a frontal wave. While
deep-layer flow will generally remain rather modest, rich low-level
moisture and strong heating will support moderate to strong buoyancy along/south of the front. Strong to potentially severe storms may
develop as the approaching shortwave trough impinges upon the
favorable buoyancy. Uncertainty regarding frontal position and the
sufficiency of deep-layer shear precludes higher confidence at this
time.

...D5/Friday: Northern Plains...
An area of interest for Friday resides across parts of the northern
Great Plains. A mid/upper-level shortwave trough is forecast to move
across the northern Rockies toward the northern High Plains, though considerable spread remains regarding the timing of this relatively low-amplitude shortwave and attendant cold front. The front may
impinge upon strong instability across parts of the Dakotas, with
scattered storm and eventual MCS development possible. Deep-layer
shear may remain relatively modest, but the magnitude of instability
will likely support some organized severe threat.

...D6/Saturday: Northern Plains/Upper Midwest...
Some continuation of severe-storm potential is possible into
Saturday, potentially shifting eastward into the Upper Midwest.
Spread in guidance becomes quite large at this range regarding
placement of the warm sector Saturday afternoon, but strong
instability and at least modest deep-layer shear could support
severe storms along/east of the cold front.

..Dean.. 06/23/2025

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

ACUS48 KWNS 240858
SWOD48
SPC AC 240857

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0357 AM CDT Tue Jun 24 2025

Valid 271200Z - 021200Z

...DISCUSSION...
Models are in good agreement with the overall pattern through
Tuesday/D8, depicting a low-amplitude trough moving from the
northwestern states on Friday/D4 across the northern tier of states
and toward the Great Lakes by around Sunday/D6. This wave is then
forecast to amplify across Ontario/Quebec through the end of the
period, with cooler/more stable air pushing south with a cold front
from the Midwest into the Northeast.

Severe storms are currently forecast over parts of the Dakotas into
northwest MN on Friday/D4 as the stronger flow aloft interacts with
a moist and unstable air mass already in place. Damaging winds
appear the most likely mode of severe, along with sporadic large
hail as storms form during the afternoon within a surface trough,
and beneath increasing winds aloft. While severe storms may also
occur on Saturday/D5 over parts of the northern Plains or upper MS
Valley, predictability is lower given expected storms the previous
day and potential for long-lived convective systems. However, given
such strong instability forecast on Saturday/D5, a risk area is
likely to be issued in later outlook cycles over parts of the upper
Midwest/MS Valley.

Elsewhere, daily thunderstorms within the moist and unstable air
mass are forecast for the bulk of CONUS from the Plains eastward,
though in a generally weak shear environment. Portions of those
areas may see low/marginal probabilities as the events enter into
the Day 3 outlook time frame.

..Jewell.. 06/24/2025

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

ACUS48 KWNS 250830
SWOD48
SPC AC 250829

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0329 AM CDT Wed Jun 25 2025

Valid 281200Z - 031200Z

...DISCUSSION...
Models are in general agreement with the upper air pattern, but
increasing spread is seen from Sunday/D5 and beyond.

On Saturday/D4, a low amplitude wave will lift out of the
ND/northern MN vicinity and move into Ontario. This will result in
temporary height rises during the day before gradual falls occur
overnight and into as a secondary wave moves from MT into the
Dakotas overnight. Early day storms may exist over parts of northern
MN in association with the low-level jet, and this activity could
weaken during the day. Then, strong instability is forecast for
several models, perhaps MUCAPE to around 5000 J/kg, over eastern SD
and NE and into IA and MN. Heating within the surface trough may
spur afternoon development from SD into NE, with some potential for
activity to spread east/northeast. However, shear will likely be
weak, with 500 mb winds averaging around 15 kt. Despite very strong instability, the weak-forcing situation in the wake of the exiting
wave suggests low-predictability at this time.

Around Sunday/D5, the secondary wave is forecast to amplify across
the upper MS Valley and upper Great Lakes, with a cold front pushing
south and extending roughly from WI to NE. Strong instability will
likely exist ahead of such a boundary, though shear will again be
weak. Still, storms will likely develop across the region, with
areas of damaging gusts potential.

From Monday/D6 through Wednesday/D8, the aforementioned trough will
spread across the Great Lakes and Northeast, with what appears to be
an end to the extreme instability levels. Scattered storms will
likely persist over much of the Southeast and Mid Atlantic, with
sporadic strong gusts daily.

..Jewell.. 06/25/2025

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

ACUS48 KWNS 260854
SWOD48
SPC AC 260852

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0352 AM CDT Thu Jun 26 2025

Valid 291200Z - 041200Z

...DISCUSSION...
On the large scale, a low-amplitude upper trough over the northern
Plains on Sunday/D4 will amplify as it moves toward the upper Great
Lakes into Monday/D5, and more so into Tuesday/D6 when it will
stretch across into the Northeast.

At the surface, high pressure will extend into the northern to
central Plains on Sunday/D4, with a trough affecting the upper MS
Valley to central Plains. This trough/front will push farther south
on Monday/D5, extending roughly from the OH Valley into the southern
Plains, and eventually, into the Gulf Coast states into Wednesday/D7
as high pressure spreads into the MS Valley.

For the period, instability looks to be strongest on Sunday/D4 ahead
of the front from NE/KS into IA/MO/IL with upper 60s to lower 70s F
dewpoints common. While unstable, only weak westerly flow aloft will
be present, and this will likely result in south to southwest
propagating cluster of storms producing areas of gusty winds. Given
substantial storm coverage over much of the central Plains to
upper/middle MS Valley, predictability remains low for denoting
precise risk areas.

A low-end risk of severe storms with wind potential could develop
into the Mid Atlantic on Tuesday/D6 as the Great Lakes/Northeast
trough amplifies with westerlies increasing to 30 to perhaps 40 kt
at 500 mb. Otherwise, scattered storms will also occur away from
this boundary, across much of the Southeast as the moisture and
instability remain in place in a weak shear environment.

..Jewell.. 06/26/2025

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

ACUS48 KWNS 270856
SWOD48
SPC AC 270855

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0355 AM CDT Fri Jun 27 2025

Valid 301200Z - 051200Z

...DISCUSSION...
A mid-level trough will amplify across the Great Lakes at the
beginning of the period D4/Monday and shift into the Northeast by
Tuesday. A surface cold front will shift east across the Great Lakes
on Monday and to the Northeast and Mid-Atlantic on Tuesday. Moderate instability may develop across a large area east of the Appalachians
on Day 5/Tuesday. The strongest shear is forecast from Pennsylvania
northward, beneath the strongest mid-level flow. However, the
greatest instability should remain mostly south of this better flow.
Therefore, a favorable corridor may develop for some strong to
severe storms near the Mid-Atlantic/Carolinas where instability and
modest shear overlap, but this remains too uncertain for severe
weather probabilities at this time.

Beyond Day 5, mid-level ridging will shift east across the central
CONUS. At the surface, high pressure will build across much of the
eastern CONUS. The combination of weak mid-level flow beneath the
mid-level ridge and surface high pressure should limit severe
weather potential for Day 6 and beyond. Strong instability is
forecast to return to the northern Plains, but given the lack of
mid-level flow, any storms will likely only be marginally severe at
best. Some stronger mid-level flow may return to the northern Plains
by next weekend as the ridge starts to break down, which may be the
next chance for more organized severe storms in the latter portion
of the extended period.

..Bentley.. 06/27/2025

= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)