SPC Convective Outlook Day 1

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824
ACUS01 KWNS 040554
SWODY1
SPC AC 040553

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1253 AM CDT Thu Jul 04 2024

Valid 041200Z - 051200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER
MISSISSIPPI VALLEY AND FROM THE MISSOURI OZARKS INTO THE SOUTHERN
PLAINS...

...SUMMARY...
Severe thunderstorms will be possible across parts of the Upper
Mississippi Valley, Ozarks, and southern Plains.

...Discussion...

Seasonally strong upper trough is shifting east across the northern
Plains early this morning. This feature is forecast to advance
toward the middle MO Valley by late afternoon as 500mb, 60kt speed
max translates across southeast NE into IA. Left exit region of this
speed max will spread across the upper MS Valley along with a
corridor of modest 12hr mid-level height falls. Latest model
guidance suggests a weak surface low will develop and track along
the MN/IA border into southwest WI by late evening. This corridor
appears favorable for robust convective development as boundary
layer warms and convective temperatures are breached, likely by
midday, as readings warm through the upper 70s-80F. Forecast
soundings exhibit veering wind profiles with height, and some
supercell potential exists within this zone of focused ascent. Large
hail and locally damaging winds are the primary concerns.

Farther south, an expansive corridor of convection has evolved over
the central Plains early this morning. Upscale growth may continue
for the next few hours, and a long-lived MCS should propagate across
eastern KS into MO by sunrise. While this complex may not be
particularly severe at daybreak, a long-lived MCS, or its remnants,
will advance downstream into the OH Valley as modest mid-level flow
will extend along a corridor from MO into southern OH. Models are
not too aggressive in steepening low-level lapse rates east of the
MS River later today, but some surface heating is expected to
contribute to increased buoyancy that will likely contribute to new
robust updrafts developing along the MCS outflow/differential-
heating zone. Will maintain MRGL risk across this region, although
somewhat higher severe probabilities may be warranted, especially
across KY along the southern flank of the forward-propagating MCS.

Later in the day, very strong surface heating across the southern
Plains will result in steep surface-3km lapse rates from northwest
TX, across central into northeast OK. As the northern Plains trough
shifts east, mid-level flow will begin to turn more westerly across
northern OK, and 500mb speeds will increase to 25-40kt north of
I-40. Convective temperatures will be breached by 22z, just ahead of
the surface front, and scattered thunderstorms should easily develop
along the wind shift. PWs will be very high across this region with
values in excess of 2 inches. With temp/dew point spreads around
30F, there is increasing confidence that the most robust convection
should generate severe downdrafts. A fairly concentrated corridor of
convection should evolve downstream into the MO Ozarks by early
evening.

..Darrow/Squitieri.. 07/04/2024

$$

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

989
FLUS43 KLOT 040833
HWOLOT

Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
333 AM CDT Thu Jul 4 2024

ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-050845-
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-
333 AM CDT Thu Jul 4 2024 /433 AM EDT Thu Jul 4 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...

Limited Thunderstorm Risk.

DISCUSSION...

Isolated thunderstorms may develop near a lake breeze this
afternoon, but the highest chances of thunderstorms is expected to
be after midnight tonight into early Friday morning, prior to 7
AM CDT.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

Friday...
Limited Thunderstorm Risk.
Sunday through Wednesday...
Limited Thunderstorm Risk.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be necessary today.

GENERAL STORM MOTION OF THE DAY:

Moving toward the east-northeast at 25 to 30 mph.

$$

LMZ740>745-050845-
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-
333 AM CDT Thu Jul 4 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...

Limited Thunderstorm Risk.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

Friday...
Hazardous conditions for small craft are possible.
Limited Thunderstorm Risk.
Sunday through Wednesday...
Limited Thunderstorm Risk.

$$

Yack

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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

471
ACUS02 KWNS 040548
SWODY2
SPC AC 040546

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1246 AM CDT Thu Jul 04 2024

Valid 051200Z - 061200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE
UPPER OHIO VALLEY...

...SUMMARY...
Marginally severe storms are most likely across parts of the upper
Ohio Valley on Friday.

...Synopsis...
An upper-level low in the Upper Midwest will continue eastward on
Saturday before becoming more of an open wave by Saturday morning. A
potent mid-level jet is anticipated across parts of the upper Ohio
Valley during the afternoon. At the surface, a low in the Lake
Michigan/Lower Michigan vicinity will also track eastward, with a
attendant cold front moving through the Ohio Valley by mid/late
afternoon and evening.

...Upper Ohio Valley...
Uncertainty remains relatively high in the degree of surface-based
destabilization that will occur by the afternoon. Morning
showers/thunderstorms are possible within a weak warm advection
regime. Further, cloud cover from the remnants of convection moving
through the lower Ohio Valley on Thursday night may also have an
impact. Given the moist airmass (low 70s F dewpoints), broken cloud
cover would still allow 1000-1500 J/kg MLCAPE (perhaps near 2000
J/kg in the southernmost areas). Effective shear will range from 35
kts to the south and increase to around 50 kts to the north. On the
lower end of destabilization, only isolated cells would be likely.
Should greater surface heating occur, a linear segment or two could
develop. Damaging winds and small hail are possible with the
strongest storms.

...Blue Ridge...
Strong heating is expected within a high PWAT airmass. Temperatures
are expected to reach the mid 90s F. Though mid-level heights will
remain neutral, convection is probable within the terrain. Weak
deep-layer shear and similarly weak anvil-level flow should keep
storm organization minimal. Confidence in more than isolated wet
microbursts is too low for highlights.

..Wendt.. 07/04/2024

$$

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

960
ACUS03 KWNS 040733
SWODY3
SPC AC 040732

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0232 AM CDT Thu Jul 04 2024

Valid 061200Z - 071200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
SOUTHERN INTO THE NORTHERN PLAINS...

...SUMMARY...
Potential for severe thunderstorms will exist across primarily parts
of the Plains on Saturday.

...Synopsis...
Broad, low-amplitude troughing aloft will be present within much of
the CONUS apart from the West Coast. Shortwave perturbations moving
through the broader trough are expected from the central Plains into
the Midwest. At the surface, a low pressure system will be in
southeastern Canada. The reservoir of richer surface moisture will
have been pushed south of a cold front that will extend from the
southern High Plains into the Mid-South and Northeast. As
northwesterly flow aloft increases across the central Rockies,
models suggest a lee surface low will develop within the CO/KS/NE
vicinity. Models do differ on the intensity of this surface low as
well as its exact position.

...Plains...
Though moisture will have been reduced behind the cold front, models
suggest that low 60s F dewpoints are possible perhaps as far north
as Nebraska. In general, thunderstorm development is possible within
the lee trough in the southern High Plains, near the surface low in
the central High Plains, and also near a weak warm front/theta-e
boundary in eastern Nebraska. The exact scenario which will produce
the greatest severe risk remains uncertain, however. Given the
remnant moisture, northwest flow advecting steep lapse rates into
the region, and shortwave trough to provide forcing for ascent, some
severe risk appears probable. At this point in time, large hail with
initial supercells and a transition to more of a severe wind threat
(given relatively large temperature-dewpoint spreads) are the
primary concerns. The outlook area will likely have to be refined as
additional guidance becomes available and confidence in corridors of
greatest risk increases.

...Mid-Atlantic...
Thunderstorms are possible along a weak cold front. Model trends
have been for less storm coverage. Additionally, the trough may
remain slightly displaced from the greatest buoyancy. Isolated
strong to severe storms are possible, but coverage is too uncertain
for highlights.

..Wendt.. 07/04/2024

$$

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

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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.