SPC Convective Outlook Day 1

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249
ACUS01 KWNS 141955
SWODY1
SPC AC 141954

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0254 PM CDT Sat Jun 14 2025

Valid 142000Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR MONTANA INTO
THE CENTRAL HIGH PLAINS...AND FROM SOUTHERN KANSAS INTO CENTRAL
OKLAHOMA...

...SUMMARY...
Scattered severe thunderstorms capable of producing large hail and
damaging wind gusts will be possible across parts of the northern
and central High Plains this afternoon and evening. Large hail and
damaging winds will also be possible this afternoon from eastern
Oklahoma into western Arkansas, and late tonight from southern
Kansas into central/northeast Oklahoma.

...20z Update...
The previous forecast largely remains on track with only minor
adjustments made to account for recent convective trends.

...Western Arkansas...
A loosely organized MCS continues to move across western AR, and
while GOES IR imagery continues to show deep/robust updraft
development, MRMS echo top imagery over the past couple of hours
reveals that these updrafts have been fairly transient, likely owing
to weak deep-layer wind shear. The MCS will likely continue to move
east/southeast towards southwestern AR through peak heating and may
be capable of damaging winds, but given the recent trends, 15%
wind/Slight risk probabilities have been removed from western AR.

...Oklahoma...
An outflow boundary is noted in visible imagery and surface
observations from south-central OK to western OK. This boundary is
sufficiently displaced from the upper cirrus associated with the MCS
to the east to yield surface temperatures in the 80s on the cool
side of the boundary. Consequently, a corridor of southeasterly
low-level flow and MLCAPE upwards of 2500-3000 J/kg is in place
across southwest/western OK and could be a preferential corridor for
a supercell or two later this evening. Latest CAM guidance has
hinted at this possibility, but solutions continue to vary.
Additional convection along and north of this boundary remains
likely later tonight as the nocturnal jet strengthens and isentropic
ascent increases. Continued re-development of elevated convection
across north-central OK casts some uncertainty on where initiation
later tonight is most likely, and may result in more focused
convection along and west of the I-35 corridor. Here again, CAM
solutions have not captured recent convective trends well and show
some variance in the exact evolution. Regardless, 15% hail/wind
probabilities have been shifted westward to account for these
trends.

...Central to Northern High Plains...
The early stages of convective initiation are underway across
central to eastern WY with further development and intensification
expected through the evening. See MCD #1286 for additional details.

..Moore.. 06/14/2025

.PREV DISCUSSION... /ISSUED 1125 AM CDT Sat Jun 14 2025/

...KS/OK/AR this afternoon through tonight...
Convection is ongoing this morning in several clusters from
southeast KS into central and eastern OK. The KS cluster had the
better defined cold pool and MCV this morning, but has weakened
while moving into the areas of rain-cooled air in the immediate wake
of the OK convection. The environment downstream into AR could
support some continuation of the eastern OK storms that have
intensified recently, with an attendant threat for occasional wind
damage and isolated large hail with multicell clusters.

The convectively-enhanced midlevel trough will remain over eastern
KS into tonight, when a southwesterly low-level jet is expected to
develop as the low levels recover in the wake of this morning's
storms. Related increases in low-level warm advection will support
new thunderstorm development tonight in roughly the same areas being
impacted by the weakening storms this morning, and an MCS could
evolve in this warm advection zone overnight. An environment with
steep midlevel lapse rates, large CAPE, and some enhancement to
low-midlevel vertical shear will favor the potential for large hail,
severe outflow gusts and a low chance for a couple of tornadoes.

...MT/central High Plains late this afternoon into late evening...
Subtle height rises are expected over the High Plains and MT, with
the stronger mid-upper flow confined mostly to MT. Forcing for
ascent will likewise be relatively weak, with some upslope flow
component along and east of a lee trough. At least widely scattered
thunderstorm development is expected east/northeast of the higher
terrain from eastern WY into northeast CO, and potentially along the
baroclinic zone across central MT. A few supercells will be
possible with large hail from MT into eastern WY, though storms with
southward extent will have more of a threat for severe outflow gusts
based on a tendency to grow upscale on merging outflow in an
environment with steep lapse rates and deep-layer vertical shear
that will be close to the lower margins for sustained supercells.
There will be some potential for a cluster or two to persist
overnight while spreading eastward over the High Plains.

...Mid-Atlantic to the southern Appalachians this afternoon...
Along and south of a stalled front from southern DE into northern
MD/VA, surface heating is ongoing in cloud breaks. As surface
temperatures warm into the 80s with 72-74 F dewpoints, MLCAPE will
increase to near 2000 J/kg this afternoon. Modest enhancement to
vertical shear (effective bulk shear of 25-30 kt) with subtle
perturbations crossing the Appalachians could allow for some
clustering of storms with the potential for isolated wind damage.

Scattered thunderstorms are expected farther southwest into the
southern Appalachians and vicinity, immediately east of the slowly
weakening midlevel trough over KY/TN. Moderate buoyancy, DCAPE
approaching 1000 J/kg and roughly 30 kt midlevel flow could be
sufficient for isolated downbursts with associated wind damage.

$$

The "Convective Outlooks" issued by SPC can be thought of as a detailed discussion of the Severe Thunderstorm threat and it's associated risks nationwide. Risk levels range from Marginal to Slight, Enhanced, Moderate, and High and are issued based on the likelihood of 3 major severe weather threats; the risk of tornadoes, damaging winds, and hail. These discussions are often heavily laced meteorological terminology that may be difficult to understand without a background in the field. However understanding these discussions shouldn't be thought of as necessary. Instead, should DuPage county fall under one of these threat levels for severe weather, the response should be to have a heightened level of awareness about the deveoloping weather. Keep an eye on the "Watch County Notification" for any active severe weather watches issued for DuPage county; the "Hazardous Weather Outlook" and "Severe Weather Statement" can also be helpful in explaining the developing risk; additionally, watch for "Active Weather Warnings" and keep an eye on our "Regional Satellite and Radar" products which can be viewed with active watches/warnings or lightning activity.

Hazardous Weather Outlook

See Product Description

848
FLUS43 KLOT 142116
HWOLOT

Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
416 PM CDT Sat Jun 14 2025

ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-152130-
Winnebago-Boone-McHenry-Lake IL-Ogle-Lee-De Kalb-Kane-DuPage-
La Salle-Kendall-Grundy-Kankakee-Livingston-Iroquois-Ford-
Northern Cook-Central Cook-Southern Cook-Northern Will-
Southern Will-Eastern Will-Lake IN-Porter-Newton-Jasper-Benton-
416 PM CDT Sat Jun 14 2025 /516 PM EDT Sat Jun 14 2025/

This Hazardous Weather Outlook is for portions of north central
Illinois...northeast Illinois and northwest Indiana.

.DAY ONE...Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Tuesday...
Elevated Thunderstorm Risk.
Wednesday...
Elevated Thunderstorm Risk...with an associated:
Level 2 of 5 Severe Thunderstorm Risk.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be necessary through tonight.

$$

LMZ740>745-152130-
Winthrop Harbor to Wilmette Harbor IL-
Wilmette Harbor to Northerly Island IL-
Northerly Island to Calumet Harbor IL-
Calumet Harbor IL to Gary IN-Gary to Burns Harbor IN-
Burns Harbor to Michigan City IN-
416 PM CDT Sat Jun 14 2025

This Hazardous Weather Outlook is for portions of the Illinois
nearshore waters of Lake Michigan and the Indiana nearshore
waters of Lake Michigan.

.DAY ONE...Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Tuesday...
Elevated Thunderstorm Risk.
Wednesday...
Elevated Thunderstorm Risk...with an associated:
Level 2 of 5 Severe Thunderstorm Risk.

$$

Borchardt

Visit us at www.weather.gov/chicago

The "Hazardous Weather Outlook" contains information regarding any and all weather expected to occur within the region that could be hazardous to travel, life or property. This is one of our most highly recommended products to check on a daily basis, and it some cases multiple times per day should significant weather be expected to affect DuPage county.

SPC Convective Outlook Day 2

See Product Description

306
ACUS02 KWNS 141726
SWODY2
SPC AC 141724

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1224 PM CDT Sat Jun 14 2025

Valid 151200Z - 161200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE NORTHERN AND CENTRAL PLAINS...

...SUMMARY...
Scattered severe storms, capable of large hail and severe wind
gusts, are expected on Sunday in parts of the northern and central
High Plains. Additional strong to severe storms are possible in
parts of North Carolina and Virginia.

...Synopsis...
An upper-level high will remain in place across the central/northern
Plains into the northern Rockies on D2/Sunday. Westerly flow aloft
will move across the ridge, with a few shortwave impulses rotating
through the flow. Afternoon thunderstorm development is expected
from the Northern Rockies southward across the dryline in the
central high Plains. A surface low is expected to deepen across
Wyoming through the period, lifting northward across the Dakotas.

...Central and Northern Plains...
As the surface low across Wyoming deepens, east to southeasterly
flow will continue across the central and northern Plains. Dew
points in the low to mid 60s will be common, allowing for strong to
moderate instability to develop by the afternoon. Upslope flow
across the northern Rockies and forcing for ascent with shortwaves
rounding the ridge will allow for scattered thunderstorm development
across the high terrain spreading into the lower elevations through
the later afternoon/evening. Generally straight hodograph profiles
will support initial supercell modes before clustering and upscale
growth occurs into the late afternoon. Given steep lapse rates and
ample deep layer shear, large to very large hail (some 2-3"+) will
be possible.

As the surface low deepens into the afternoon, mass response will
occur with an increase in a southerly low-level jet into the western
Dakotas. CAM guidance shows some uncertainty in evolution of storms
as they move eastward out of Montana. There is consistent signal
that an MCS will travel eastward across some portions of the
Dakotas, with potential for strong to significant winds (60-75+
mph). Should a more favorable corridor become established, an
upgrade to higher probabilities may be needed.

...Southern/South-Central Plains into the Missouri Valley...
An MCS will likely be ongoing across portions of Oklahoma into
northern Texas early in the period. Residual outflow in association
with this will set up across portion of north-central Texas into
Missouri. Convective re-development may be somewhat inhibited due to
warm air aloft and the presence of the mid-level ridge. In spite of
this, some convection will be possible as low-level convergence
increases during the day along pre-existing outflow boundaries.
Mid-level directional shear is evident on forecast soundings. This
could be sufficient for some cell organization and a severe threat.
Hail and strong wind gusts would be possible.

...Northern North Carolina/Southern Virginia...
A subtle mid-level shortwave trough is forecast to move into the
southern and central Appalachians on Sunday. At the surface, a lee
low is forecast to develop over central North Carolina. Scattered
thunderstorm activity is expected to develop by the afternoon across
northern North Carolina into southern Virginia. Sufficient deep
layer and instability will allow for a few instances of severe wind
and hail within stronger cores.

..Thornton.. 06/14/2025

$$

The "Convective Outlooks" issued by SPC can be thought of as a detailed discussion of the Severe Thunderstorm threat and it's associated risks nationwide. Risk levels range from Marginal to Slight, Enhanced, Moderate, and High and are issued based on the likelihood of 3 major severe weather threats; the risk of tornadoes, damaging winds, and hail. These discussions are often heavily laced meteorological terminology that may be difficult to understand without a background in the field. However understanding these discussions shouldn't be thought of as necessary. Instead, should DuPage county fall under one of these threat levels for severe weather, the response should be to have a heightened level of awareness about the deveoloping weather. Keep an eye on the "Watch County Notification" for any active severe weather watches issued for DuPage county; the "Hazardous Weather Outlook" and "Severe Weather Statement" can also be helpful in explaining the developing risk; additionally, watch for "Active Weather Warnings" and keep an eye on our "Regional Satellite and Radar" products which can be viewed with active watches/warnings or lightning activity.

SPC Convective Outlook Day 3

See Product Description

249
ACUS03 KWNS 141931
SWODY3
SPC AC 141931

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0231 PM CDT Sat Jun 14 2025

Valid 161200Z - 171200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE
NORTHERN/CENTRAL GREAT PLAINS INTO THE UPPER MIDWEST...

...SUMMARY...
Scattered severe storms with isolated large hail and wind damage are
expected on Monday from the northern High Plains east-northeastward
into the upper Mississippi Valley. Outside of this area, marginally
severe storms will be possible across much of the central and
northern U.S.

...Synopsis...
A belt of mid-level westerly flow will move across the central/high
Plains on D3/Monday, dampening ridge heights and creating a more of
a zonal flow regime. A surface low will deepen across eastern
Colorado, with a southwest to northeast oriented cold front shifting
south and eastward across Nebraska through the period.

...Great Plains/Upper Midwest..
Convection is likely to be ongoing across portions of North
Dakota/Minnesota. Additional thunderstorm development is expected
along the aforementioned cold front in Nebraska/southern Dakotas by
Monday afternoon. Guidance suggest there will be MLCIN in place
across some portion of the central plains, weakening with northward
extent into central Nebraska. Forcing for ascent is along expected
to be greatest in the region from central Nebraska into southern
South Dakota with the advancing wave and cold front, which should
aid eroding of remaining CIN. Deep layer shear largely parallel to
the cold front should encourage linear modes, with potential for
damaging wind given steep low to mid-level lapse rates. This should
advance eastward along the front into portions of the Upper Mid-west
through time.

More isolated development may be possible across portions of the
central Plains, though warmer 850 mb temperatures and stronger MLCIN
beneath higher heights will keep the overall severe threat more
marginal. Forecast soundings suggest that moderate deep-layer shear
and steep mid-level lapse rates will be in place over much of the
moist air mass. This should support an isolated severe threat, with
hail and strong wind gusts possible.

..Thornton.. 06/14/2025

$$

The "Convective Outlooks" issued by SPC can be thought of as a detailed discussion of the Severe Thunderstorm threat and it's associated risks nationwide. Risk levels range from Marginal to Slight, Enhanced, Moderate, and High and are issued based on the likelihood of 3 major severe weather threats; the risk of tornadoes, damaging winds, and hail. These discussions are often heavily laced meteorological terminology that may be difficult to understand without a background in the field. However understanding these discussions shouldn't be thought of as necessary. Instead, should DuPage county fall under one of these threat levels for severe weather, the response should be to have a heightened level of awareness about the deveoloping weather. Keep an eye on the "Watch County Notification" for any active severe weather watches issued for DuPage county; the "Hazardous Weather Outlook" and "Severe Weather Statement" can also be helpful in explaining the developing risk; additionally, watch for "Active Weather Warnings" and keep an eye on our "Regional Satellite and Radar" products which can be viewed with active watches/warnings or lightning activity.

Special Weather Statement

See Product Description

No active Special Weather Statement for DuPage County.

The "Special Weather Statement" details notable weather either occuring or expected to occur, but does not necessarily have to be considered severe or hazardous. This is a supplementary product issued by the National Weather Service to help describe noteworthy weather. It's terminology should be reasonably easy to understand by the general public.

Watch County Notification

See Product Description

No active Watch County Notification for DuPage County.

The "Watch County Notification" will contain updates regarding active severe weather watches that pertain to DuPage county. This may be for a newly issued watch, or the cancelation of an existing watch. Severe weather watches come in two forms; Severe Thunderstorm and Tornado, and it should be noted that a Severe Thunderstorm Watch does NOT rule out the possibility of tornadoes occuring. It generally means that the tornado threat is minimal while damaging winds and hail are still likely. See our "Watch, Warning, and Advisory Criteria" for more detailed information on the differences and critera for watches, warnings and advisory for all forms of weather.

Winter Weather Statement

See Product Description

No active Winter Weather Statement for DuPage County.

The "Winter Weather Statement" is a product aimed at the general public that will discuss impacts caused by winter weather. This may include information about watches, warnings and advisories as well as details about impactful winter weather that may not warrant the issuance of a watch, warning or advisory.

Severe Weather Statement

See Product Description

No active Severe Weather Statement for DuPage County.

The "Severe Weather Statement" is a product aimed at the general public that will discuss impacts caused by severe thunderstorms. This may include information about watches and warnings as well as details about impactful "sub-severe" weather that may not warrant the issuance of a watch or warning which sometimes may come when a watch or warning has been canceled.

Non-Precip Statement

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No active Non-Precip Statement for DuPage County.

The "Non-Precip Statement" is aimed at the general public and will detail notable weather that is either occuring or expected to occur, but does not relate to any form of precipitation. These would include but are not limited to high winds, reduced visibility or extreme temperatures.

Active Weather Warnings

Tornado Warnings

No active Tornado Warnings.

Severe Thunderstorm Warnings

No active Severe Thunderstorm Warnings.

Flood Warnings

No active Flood Warnings.

General Tornado/Severe Weather Safety

1. A Tornado or Severe Thunderstorm Warning is issued when it has been reported, or when it has been detected via National Weather Service radar. It is to be interpreted that this event is occuring and is expected to affect all warned areas. Those within the warning need to take action immediately.
2. If under a warning remain calm and if it is necessary to seek shelter. Students and Employees should head to their nearest designated shelter area. The route to these shelter areas are posted in all rooms on campus and signs are placed in the hallways to direct you to the nearest shelter area. Review these instructions and be familiar with where your nearest shelter is. Stay indoors, away from windows and large unsupported ceilings. Faculty should account for their students and Supervisors should account for their areas employees.
3. If outside, take shelter in the nearest building.
4. After the storm has passed, dial Police at 911 to report any injuries or damage to buildings.
5. If the building is severely damaged, evacuate the building as soon as possible after the storm has passed.