SPC Convective Outlook Day 1

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821
ACUS01 KWNS 050549
SWODY1
SPC AC 050548

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1248 AM CDT Mon May 05 2025

Valid 051200Z - 061200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS FAR
SOUTHEAST NEW MEXICO INTO SOUTHWEST TEXAS...

...SUMMARY...
Severe thunderstorms are expected from the southern High Plains into
parts of central Texas this afternoon and evening. Scattered large
to very large hail and severe winds are the primary threats, though
a couple of tornadoes also are possible. Additional strong to severe
storms are possible along the eastern Florida coast and from eastern
North Carolina into the central Appalachians and upper Ohio River
Valley.

...Synopsis...
An omega blocking pattern continues to develop over the CONUS per
recent water-vapor imagery and 00 UTC upper-air analysis, with two
meandering upper lows over the Ohio River Valley and Southwest
respectively. Northward moisture advection and ascent on the eastern
periphery of both upper lows will promote another day of scattered
thunderstorms (including strong to severe storms) across the central
Appalachians/Mid-Atlantic and southern High Plains into the
Intermountain West.

...Southern High Plains...
Upper-level diffluence over the southern High Plains will continue
to promote gradual surface pressure falls and a southeasterly return
flow regime across far eastern NM and western TX through much of the
day. Although moisture return will initially be somewhat modest,
persistent broad-scale ascent over the region will result in cooling
temperatures aloft/steepening mid-level lapse rates that should
compensate for the poor moisture quality. Thunderstorm development
is expected initially within a warm advection regime across
south-central TX by early afternoon with additional storm
development by late afternoon across the Permian basin in closer
proximity to a deepening lee trough/sharpening dryline. Across both
regions, deep-layer wind shear on the order of 50 knots should
promote supercells with an attendant threat for large hail. Across
south-central TX, higher-quality moisture and stronger veering in
the lowest 1-2 km AGL may support a tornado threat.

By early evening, a shortwave trough embedded within the mean flow
(observable in water-vapor imagery off the southern CA coast as of
06 UTC) is forecast to overspread southwest TX. Stronger surface
pressure falls associated with this shortwave will induce
strengthening low-level winds, which will not only enlarge low-level
hodographs, but will augment moisture return into the region. Ascent
within the strengthening warm advection regime should result in
scattered supercell development between 00-06 UTC across the
southern Permian Basin and adjacent areas of southeast NM. Given the
increasingly favorable convective environment, a few long-lived
supercells appear possible and will be capable of producing large to
very large (2+ inch) hail and perhaps a couple of tornadoes. Upscale
growth into one or more clusters appears likely heading into the
overnight hours as lift spreads northeast into northwest and central
TX. There remains some uncertainty among guidance regarding the
development of a more organized MCS into TX through early Tuesday
morning, but cells developing within the warm advection regime ahead
of the upper wave may be capable of severe hail/wind.

...Central Appalachians and Mid-Atlantic...
Recent surface observations reveal a residual front/marine boundary
draped from eastern VA into the eastern Carolinas. East of this
boundary, richer low-level moisture in the form of low to mid-60s
dewpoints is noted extending northward into southeast PA. Aloft, an
embedded shortwave orbiting around the primary upper low is noted
over the mid-MS River Valley in recent water-vapor imagery. This
feature is expected to pivot into the Mid-Atlantic and central
Appalachians through the afternoon/evening and will be favorably
timed with the diurnal heating cycle. The combination of cold
temperatures aloft in proximity to the upper low and rich low-level
moisture will limit capping and promote thunderstorm initiation
along the boundary by early afternoon from the DelMarVa region into
NC. Further to the northwest, lift ahead of the embedded shortwave
combined with cold mid-level temperatures should promote
thunderstorm development across WV and OH by late afternoon. Across
both regions, 1000-1500 J/kg MLCAPE and elongated, nearly straight
hodographs should promote organized cells capable of large hail and
damaging winds. Similar thermodynamic and kinematic environments
were observed yesterday across the region, and yielded isolated to
scattered strong to severe thunderstorms, including a couple of
supercells.

...Eastern Florida Coast...
Regional 00 UTC soundings sampled somewhat steep mid-level lapse
rates atop a seasonally moist boundary layer (characterized by upper
60s to low 70s dewpoints) with limited inhibition. Heating of this
air mass should eliminate any residual capping by late morning and
early afternoon as temperatures climb into the 80s. Convective
initiation will become more probable by mid/late afternoon as
confluence along sea-breeze boundaries increases. Isolated to
scattered thunderstorms are expected, and 30-40 knot mid-level flow
should promote a few organized cells capable of producing large hail
and damaging gusts.

..Moore.. 05/05/2025

$$

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.

Hazardous Weather Outlook

See Product Description

006
FLUS43 KLOT 050928
HWOLOT

Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
428 AM CDT Mon May 5 2025

ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-060930-
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-
428 AM CDT Mon May 5 2025 /528 AM EDT Mon May 5 2025/

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

.DAY ONE...Today and Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be necessary through tonight.

$$

LMZ740>745-060930-
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-
428 AM CDT Mon May 5 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...Today and Tonight.

Hazardous conditions for small craft early this morning.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Wednesday and Thursday...
Hazardous conditions for small craft are likely.

$$

Ratzer

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

649
ACUS02 KWNS 050600
SWODY2
SPC AC 050559

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1259 AM CDT Mon May 05 2025

Valid 061200Z - 071200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL TEXAS
INTO THE SABINE VALLEY...

...SUMMARY...
Severe thunderstorms are possible from portions of the southern
Plains into the lower Mississippi Valley on Tuesday. Severe winds,
large to very large hail, and a few tornadoes are possible.
Additional isolated strong to severe storms capable of large hail
and isolated wind damage are possible within parts of the northern
Mid-Atlantic states.

...Synopsis...
With the blocking pattern still in place, the upper lows in the Ohio
Valley and Southwest will continue to make slow progress on Tuesday.
A shortwave trough on the base of the upper low is expected to eject
into the southern Plains. This will promote severe potential across
much of the region into the Lower Mississippi Valley. Rich moisture
will continue to push into much of Texas and a warm front will lift
to near the Red River.

...Central/East Texas into Western Louisiana...
A complicated forecast exists across these regions. Convection is
anticipated to develop in West Texas along a retreating dryline late
on Day 1/Monday. Models are in general agreement that some of this
activity will persist into Tuesday morning in central Texas. A very
moist airmass (mid 60s to low 70s F dewpoints) will be advecting
northward/westward ahead of this activity. There is some potential
for this activity to remain slightly elevated given the early
morning timing and some overnight boundary layer cooling. However,
high theta-e advection will also mitigate inhibition. Though this
uncertainty remains, the Slight risk has been moved farther westward
in central Texas to account for potential near-surface/surface based
storms early on Tuesday. Additional early morning activity is
expected along the northward lifting warm front as the shortwave
trough ejects into the southern Plains and the low-level jet
impinges on the boundary.

How this morning activity evolves will greatly impact the potential
for higher-end severe storms in the afternoon and what the greatest
severe hazard will be. The very moist airmass and steep mid-level
lapse rates will promote a zone of 2500-3500 J/kg MLCAPE in parts of
Central/East Texas south of the warm front. With greater than 50 kts
of effective shear, all severe hazards would be possible regardless
of the ultimate evolution of the convection. That being said, there
appears to be a corridor of conditionally higher severe potential
near and just south of the warm front in Northeast Texas into
northwest Louisiana. Should a more organized cluster/MCS persist
through Monday night into Tuesday morning, there is greater
potential for a swath of severe wind gusts as the airmass
destabilizes ahead of it. Without the MCS, there is greater
potential for storms developing along the warm front to produce
tornadoes (perhaps strong) as the strong low-level jet and fringe of
the steeper lapse rates will overlap.

Given the weakly capped boundary layer even early in the day, there
is reasonable confidence in numerous storms, particularly along the
warm front. With large amounts of storm interference possible, on
top of potential MCS, confidence is not high enough to increase
tornado probabilities. Concerning the MCS and greater severe wind
potential, models vary greatly on the placement of this feature.
Similarly, confidence is too low for higher wind probabilities as
well. Overall, scattered to numerous storms along the warm front and
dryline in central Texas will be capable of all severe hazards. Very
large hail is most likely along the dryline or with storms that
develop along the southern edge of any MCS.

...Red River Vicinity...
Storms near the Red River and northward are more likely to be
elevated. Large hail and perhaps isolated damaging gusts could
occur. There is some tornado potential south of the Red River into
North Texas where storms will be at least near-surface based.

...Texas Panhandle...
With the upper-level low moving into parts of the Panhandle and weak
surface low in the South Plains, there is potential for moisture to
remain along a surface boundary. Several models show low 50s F
dewpoints in the region. The question will be how much surface
heating occurs. Should sufficient buoyancy develop, cold
temperatures aloft will promote potential for marginally severe hail
and isolated severe gusts in the strongest storms.

...Northern Mid-Atlantic...
With the Upper Ohio Valley cyclone moving slowly northeast, there
will be potential for another round of convection to develop near
the core of the upper low where greater surface heating occurs.
Marginally severe hail and isolated wind damage will be possible
with storms during the afternoon.

...South Texas...
Forcing for ascent will be somewhat weak during the afternoon and
storm development is not certain. Some model guidance suggests that
storms could form during the overnight near the Rio Grande Valley as
a shortwave impulse moves over South Texas and adjacent Mexico.
Large hail and severe winds would be possible with any supercells
that can develop.

..Wendt.. 05/05/2025

$$

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

099
ACUS03 KWNS 050727
SWODY3
SPC AC 050727

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0227 AM CDT Mon May 05 2025

Valid 071200Z - 081200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Potential for organized severe weather is expected to be low on
Wednesday.

...Synopsis...
An elongated upper low within the Southwest into the southern Plains
will weaken as it slowly moves eastward on Wednesday. The strongest,
but decreasing with time, mid-level winds will reside along the Gulf
Coast. At the surface, weak boundaries are expected to extend from
the lower Mississippi Valley into South Texas.

At the start of the period, convection is expected to be in portions
of the lower Mississippi Valley. This activity should be moving into
a stable airmass and does not currently appear that it will pose an
organized severe threat. Models differ in the expansiveness of this
convective activity. The NAM in particular shows outflow stalling in
southern Louisiana into the Upper Texas Coast. If this were to
occur, a very moist airmass and lingering moderate mid-level flow
could allow for a zone of strong to severe storms near the outflow
boundary. The ECMWF/GFS push outflow offshore. There is additional
potential for strong to severe storms in South Texas. However, some
capping will be in place and mid-level heights will be neutral.
Confidence in organized severe weather remains too low for
probabilities at this time.

..Wendt.. 05/05/2025

$$

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

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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.