SPC Convective Outlook Day 1

See Product Description

586
ACUS01 KWNS 270754
SWODY1
SPC AC 270753

Day 1 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0253 AM CDT Sat Apr 27 2024

Valid 271200Z - 281200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
NORTH TEXAS...OKLAHOMA...SOUTHEAST KANSAS AND FAR SOUTHWEST
MISSOURI...

CORRECTED FOR GEOGRAPHIC REFERENCE IN MISSOURI

...SUMMARY...
Numerous severe thunderstorms are likely today and tonight across
the southern and central Plains into the lower to mid Missouri
Valley. The greatest potential for severe storms will be from north
Texas into Oklahoma and southeast Kansas, where strong tornadoes,
very large hail over 2 inches in diameter and widespread damaging
winds (some over 70 mph), are expected to occur. A broader area of
severe threat will extend from south-central Texas
north-northeastward to the Great Lakes.

...Tornado Outbreak Expected Today From North Texas into
Oklahoma...Southeast Kansas and Far Southwest Missouri...

...Southern Plains...
An upper-level trough will move through the Desert Southwest today
as an 80 to 90 knot mid-level jet translates quickly eastward
through the base of the system. Ahead of the trough, a moist and
unstable airmass will be in place across much of the southern and
central Plains. At the surface, a low will move eastward across
southwest Kansas with a dryline extending southward through far
western Oklahoma and west Texas. Surface dewpoints to the east of
the dryline will be in the mid to upper 60s F. In response to warm
advection this morning, a cluster of thunderstorms is expected to
develop to the east of the dryline across northwest Texas. This
cluster is forecast to spread north-northeastward into western
Oklahoma by late morning. Large hail and wind damage will be likely
with the stronger cells within this cluster. An outflow boundary
with this convection should setup across west-central Oklahoma by
early afternoon, with a moist and unstable airmass extending
eastward from the boundary across much of central and eastern
Oklahoma northward into southeast Kansas. This undisturbed airmass
is expected to be favored for the greatest severe threat this
afternoon and evening.

The mid-level jet is forecast to eject quickly northeastward across
the southern Plains this afternoon. This will result in strong
deep-layer shear across most of the southern Plains, and will create
a large-scale mass response that will be very favorable for severe
storms, including supercells and bowing line segments. As the core
of the mid-level jet moves into the southern Plains during the mid
to late afternoon, a 50 to 60 knot low-level jet will rapidly
strengthen. RAP forecast sounding along and near the low-level jet
during the late afternoon look very favorable for tornadoes, with
backed surface flow, and long looping hodographs. As the low-level
jet strengthens, 0-3 km storm-relative helicity is forecast to
increase to around 400 m2/s2 across much of central and eastern
Oklahoma into southwest Missouri. The more dominant and supercells
that interact with the western and northern edge of the low-level
jet are expected to become tornadic. Several strong tornadoes will
be likely, and a few long-track EF3+ tornadoes will be possible.

In addition to the tornado threat, forecast soundings have 700-500
mb lapse rates near 8 C/km across much of the warm sector this
afternoon from north Texas to southeast Kansas. This will be
favorable for very large hail, with hailstones over 2 inches in
diameter likely with the more intense storms. Later in the evening,
a line of severe storms is expected to form, moving eastward across
eastern Oklahoma and north Texas. Wind gusts over 70 mph will be
possible with the more intense parts of the line. QLCS tornadoes
will also be possible with rotating cells embedded in the line late
this evening into the overnight period.

...Central Plains/Lower to Mid Missouri Valley...
An upper-level low will move through the southern Rockies today, as
the exit region of a mid-level jet overspreads the central Plains.
At the surface, a warm front will be located from near a surface low
in southwest Kansas east-northeastward into the mid Missouri Valley.
This front will be a focus for convective development this
afternoon. A band of severe storms is expected to form near the
front and move northward across northern Kansas into southern
Nebraska during the early to mid afternoon. RAP forecast soundings
in northeast Kansas near the front from 18Z to 21Z have MLCAPE near
3000 J/kg, 0-6 km shear around 60 knots, and steep low to mid-level
lapse rates. This environment will be very favorable for supercells
with large hail. Hailstones greater than 2 inches in diameter will
be possible with the more intense storms. In addition, forecast
soundings have 0-3 km storm-relative helicity in the 250 to 300
m2/s2 range, suggesting that tornadoes will be likely with the more
discrete supercells. A few strong tornadoes will be possible.

Further west into northwest Kansas and eastern Colorado, cold
temperatures aloft, strong large-scale ascent associated with an
upper-level low, and strong deep-layer shear will likely support
lower-topped supercells with large hail and strong wind gusts this
afternoon.

...Mid to Upper Mississippi Valley/Great Lakes...
An upper-level trough will move northeastward across the Great Lakes
region today. From near the trough, and southwestward into the mid
to upper Mississippi Valley, a wide corridor of moderate instability
will be in place by afternoon. A warm front will be in located along
the northern edge of the instability, from Iowa northeastward into
south-central Wisconsin and north-central lower Michigan. As surface
heating takes place and low-level convergence increases along the
front, thunderstorms will likely form in the vicinity of the
boundary. Forecast soundings near the front at 21Z have MLCAPE
around 3000 J/kg, along with 40 knots of deep-layer shear. This
should support supercells with potential for large hail and wind
damage. The severe threat should be greatest during the late
afternoon and early evening.

..Broyles/Thornton.. 04/27/2024

$$

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

425
FLUS43 KLOT 270906
HWOLOT

Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
406 AM CDT Sat Apr 27 2024

ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-280915-
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-
406 AM CDT Sat Apr 27 2024 /506 AM EDT Sat Apr 27 2024/

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

.DAY ONE...Today and Tonight.

Weather hazards expected...

Elevated Thunderstorm Risk...with an associated:
Limited Hail Risk...up to Quarter size.
Limited Damaging Wind Risk...up to 60 mph.
Limited Tornado Risk.
Limited Flooding Risk.

DISCUSSION...

Isolated showers and thunderstorms may develop as early as this
afternoon with coverage increasing tonight. Tonight's storms will
have some potential to produce damaging winds and large hail,
mainly to the west of a LaSalle to Waukegan line. There will also
be some potential for localized flash flooding tonight.

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

Sunday...
Limited Severe Thunderstorm Risk.
Limited Flooding Risk.
Monday...
Limited Thunderstorm Risk.
Tuesday night through Friday...
Limited Thunderstorm Risk.

DISCUSSION...

Additional showers and storms are expected Sunday night, some of
which could be severe. A few non-severe storms may continue into
Monday.

An active weather pattern returns midweek with multiple periods
of showers and storms Tuesday night through Friday.

.SPOTTER INFORMATION STATEMENT...

Spotters may be needed this evening.

GENERAL STORM MOTION OF THE DAY:

Moving toward the northeast at 40 mph.

$$

LMZ740>745-280915-
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-
406 AM CDT Sat Apr 27 2024

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...Today and Tonight.

Weather hazards expected...

Hazardous conditions for small craft.
Elevated Thunderstorm Risk...with an associated:
Limited Hail Risk...up to Quarter size.
Limited Thunderstorm Wind Gust Risk...up to 50 kts.

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

Sunday...
Limited Thunderstorm Risk.
Monday...
Hazardous conditions for small craft are likely.
Limited Thunderstorm Risk.
Tuesday night through Friday...
Limited Thunderstorm Risk.

$$

Petr

Visit us at www.weather.gov/chicago

Follow us on Facebook, Twitter, and Youtube at:
www.facebook.com/nwschicago
www.twitter.com/nwschicago
www.youtube.com/nwschicago

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

557
ACUS02 KWNS 270559
SWODY2
SPC AC 270557

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1257 AM CDT Sat Apr 27 2024

Valid 281200Z - 291200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EAST TX
NORTHWARD INTO THE UPPER MS VALLEY...

...SUMMARY...
Strong to potentially severe thunderstorms will be possible Sunday
from northeast Texas into parts of the upper Mississippi Valley.
Damaging winds, hail, and a few tornadoes will all be possible.

...East TX into the upper MS Valley...
A broad region of at least some severe potential is still expected
on Sunday from northeast TX into parts of the upper MS Valley.
Within this larger region, it appears the greatest relative threat
may develop from northeast TX/southeast OK into western AR/northwest
LA. However, with very extensive convection expected upstream on
D1/Saturday, uncertainty is too high to increase probabilities at
this time.

A negatively tilted shortwave trough and attendant surface low are
forecast to move from the central Plains toward the upper MS Valley
on Sunday. Widespread convection will likely be ongoing at the start
of the period from Texas toward the lower MO Valley, and potentially
farther north into parts of the upper Midwest. Some lingering severe
threat could accompany this morning convection, especially toward
the ArkLaTex region where somewhat more favorable
moisture/instability will be in place.

There is some potential for morning convection to remain somewhat
organized and continue eastward with a severe threat, but the
greater concern will be with redevelopment in the wake of morning
convection, with rich low-level moisture expected to remain in place
along/ahead of the dryline, which will likely extend from eastern
NE/KS into central OK/TX by late afternoon.

One area of potential redevelopment will be immediately ahead of the
ejecting shortwave trough from eastern KS/NE into western MO and
southern IA, where a few stronger cells/clusters could pose a threat
of hail, isolated damaging gusts, and a tornado or two. The
magnitude of this threat will be strongly dependent on the extent of
diurnal destabilization in the wake of morning convection.

Potentially more vigorous redevelopment will be possible along the
western/southern periphery of remnant early convection near the
ArkLaTex region, where rich moisture and favorable wind profiles
will support organized convection, if sufficient
recovery/destabilization can occur. Supercells will be possible,
though there may be a tendency toward cluster or linear mode as
storm coverage increases. Damaging gusts, hail and a few tornadoes
will be possible within this regime, though magnitude and favored
placement of the threat remain uncertain at this time.

...Northeast OH into PA...
A few stronger storms will be possible Sunday afternoon from
northeast OH into PA, within a weakly forced northwest-flow regime.
At this time, instability appears too weak to support an organized
severe threat, though small hail and gusty winds will be possible
with the strongest storms.

..Dean.. 04/27/2024

$$

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

610
ACUS03 KWNS 270730
SWODY3
SPC AC 270729

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0229 AM CDT Sat Apr 27 2024

Valid 291200Z - 301200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM
CENTRAL/SOUTH TX INTO THE LOWER MS VALLEY...

...SUMMARY...
Isolated strong to severe thunderstorms will be possible on Monday
from parts of central and south Texas into the lower Mississippi
Valley.

...Synopsis...
A shortwave trough initially near the upper Great Lakes region is
forecast to gradually weaken and move northeastward on Monday. In
its wake, a low-amplitude shortwave trough is forecast to move
across the southern Plains. Across the west, a shortwave trough and
related mid/upper-level jet will move through the Northwest toward
the northern Rockies by Monday evening.

...ArkLaTex into the Lower MS Valley...
A storm cluster may be ongoing somewhere near the ArkLaTex region
Monday morning, aided by a persistent low-level jet and the
approaching low-amplitude shortwave trough. The eastward progression
of any such cluster and magnitude of downstream destabilization
remain quite uncertain, but some threat for isolated hail, damaging
wind, and possibly a tornado could spread into the lower MS Valley
through the day.

...Parts of central/south TX...
An outflow reinforced front may move into parts of central TX early
Monday, in the wake of extensive ongoing convection father east.
This front will may stall and either begin moving northward by
afternoon, or just become increasingly ill-defined with time. While
stronger ascent will move east/northeast of this region, strong
heating of a moist airmass will result in moderate to locally strong
destabilization, and isolated storm development will be possible.
Deep-layer shear will remain sufficient for some storm organization,
so any sustained development would pose a threat for hail and
isolated severe gusts.

...Parts of the Mid MS and OH Valleys into the lower Great Lakes
region...
A weakening cold front will move through parts of the Mid MS and OH
Valleys during the day on Monday, with the front expected to reach
parts of the lower Great Lakes by Monday evening. While moderate
deep-layer flow may persist along/ahead of the front,
destabilization may be quite limited due to considerable cloudiness
and weakening midlevel lapse rates. While a strong storm or two
cannot be ruled out along/ahead of the front, uncertainty regarding
the development of adequate instability precludes probabilities at
this time.

..Dean.. 04/27/2024

$$

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

See Product Description

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.

Winter Weather Warnings

No active Winter Weather 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.