SPC Convective Outlook Day 1

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726
ACUS01 KWNS 230058
SWODY1
SPC AC 230057

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0757 PM CDT Wed May 22 2019

Valid 230100Z - 231200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FROM
NORTHEASTERN OKLAHOMA INTO SOUTHEASTERN KANSAS AND WESTERN
MISSOURI...

...SUMMARY...
Severe thunderstorms will continue through the evening from Oklahoma
into Missouri and central Illinois and Indiana. Tornadoes,
large/damaging hail and severe gusts all are possible.

...01Z Outlook Update...
A cluster of tornadic supercells have evolved in northeastern
Oklahoma and vicinity, with additional storms extending
northeastward along/near a cold front extending from near Kansas
City northeastward to west-central Illinois. Observational trends
suggest that a threat for tornadoes (a few significant) and very
large hail/damaging wind gusts will continue with this activity for
the next several hours (especially in the Moderate Risk area) even
as storms begin the process of growing upscale into one or two
linear complexes (Reference MCD 740 for more mesoscale details).
Guidance also shows that these storms will begin to propagate more
easterly across Illinois and into central/northern Indiana and
vicinity along and just north of a reservoir of moderate instability
over southern Illinois and vicinity amidst continued strong deep
shear. The Marginal and Slight risk areas have been extended
eastward through central Illinois and Indiana as a result.

Farther southwest into Oklahoma, negligible inhibition was noted on
the 00Z RAOB from OUN along with supercellular kinematic profile and
strong instability. Convective coverage continues to be a bit
uncertain given weak synoptic forcing for ascent, however storms
that persist through the evening will continue to pose a threat for
all modes of severe, including significant hail and tornadoes.
Reference MCD 741 for more details in this area.

..Cook.. 05/23/2019

$$

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

240
FLUS43 KLOT 222030
HWOLOT

Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
330 PM CDT Wed May 22 2019

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
232030-
Winnebago-Boone-McHenry-Lake-Ogle-Lee-De Kalb-Kane-DuPage-Cook-
La Salle-Kendall-Grundy-Will-Kankakee-Livingston-Iroquois-Ford-
Porter-Newton-Jasper-Benton-
330 PM CDT Wed May 22 2019 /430 PM EDT Wed May 22 2019/

This Hazardous Weather Outlook is for portions of North Central
Illinois...Northeast Illinois and Northwest Indiana.

.DAY ONE...Tonight.

Weather hazards expected...

Significant Thunderstorm Risk...with an associated:
Limited Tornado risk.
Elevated hail risk...up to golf ball size.
Elevated damaging wind risk...up to 70 mph.
Elevated Flooding Risk.

DISCUSSION...

Thunderstorms will develop this evening and continue into the
overnight hours. Some of the storms could become severe with
damaging up to 70 mph and hail up to the size of golf balls
being the primary threats, however there is a small tornado
risk, especially southwest of a Dixon to Pontiac line.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Thursday...
Limited Flooding Risk.
Limited Thunderstorm Risk.
Friday...
Elevated Severe Thunderstorm Risk.
Limited Flooding Risk.
Saturday through Tuesday...
Limited Thunderstorm Risk.

DISCUSSION:

There will be periodic chances of thunderstorms late Friday night through
early next week. Some of the storms could be severe Friday into Friday
evening. These storms also pose a flash flooding concern Friday night.

.SPOTTER INFORMATION STATEMENT...

Spotters may be needed between 8 pm this evening and 3 am late
tonight.

GENERAL STORM MOTION OF THE DAY:

Moving toward the northeast at 35 to 40 mph.

$$

LMZ740>745-232030-
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-
330 PM CDT Wed May 22 2019

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.

Weather hazards expected...

Hazardous conditions for small craft.
Elevated Thunderstorm Risk...with an associated:
Limited hail risk...up to golf ball size.
Limited thunderstorm wind gust risk...up to 60 knots.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Thursday...
Limited Thunderstorm Risk.
Friday...
Elevated Severe Thunderstorm Risk.
Saturday and Sunday...
Limited Thunderstorm Risk.
Tuesday...
Limited Thunderstorm Risk.

$$

Izzi/KMD

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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

366
ACUS02 KWNS 221807
SWODY2
SPC AC 221807

Day 2 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0107 PM CDT Wed May 22 2019

Valid 231200Z - 241200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE OH
VALLEY/MIDDLE ATLANTIC AND SOUTHERN/CENTRAL PLAINS...

CORRECTED FOR MISSING THUNDER LINE

...SUMMARY...
Severe storms with large hail, damaging wind and tornadoes will be
possible over a part of the central and southern Plains Thursday.
Other severe storms with a threat for mainly damaging wind and large
hail are expected from a portion of the Ohio Valley into the
northern Middle Atlantic.

...Upper OH Valley/Northern Middle Atlantic...

Central US short-wave trough is forecast to eject northeast across
the Great Lakes and flatten the eastern ridge as 80kt 500mb speed
max translates across Lake Erie. This feature is expected to aid
early-morning convection across the OH Valley which will propagate
into eastern OH/western PA by 18z. Depending on the evolution of
this convection it appears environmental shear will become favorable
for sustaining fast-moving organized updrafts. Latest model guidance
suggests upward-evolving thunderstorms by early afternoon within
strengthening westerly flow regime. Boundary-layer heating is
expected to be maximized from south-central PA, south along the lee
of the central Appalachians. If a cold pool develops early, severe
thunderstorms should initiate along the
eastern-southern-southwestern flank of this activity then
spread/develop east-southeast toward the Delmarva. Several CAMs
solutions support this scenario and will extend higher severe probs
into northern MD to account for the more southeast propagational
component. Damaging winds, and some hail, are expected with
convection as it spreads across eastern OH/PA toward northern MD by
late afternoon.

...Central/Southern Plains...

Strong mid-level flow is forecast to round the base of western US
trough over northern Mexico late day1 into early day2, then
translate into the central High Plains by 24/00z. In response to
this feature, LLJ should strengthen across the TX south Plains late
Wednesday. This will allow for a substantial moisture surge to at
least 102W longitude where higher terrain and heating along the
western edge of this moist plume should contribute to robust
convection. There is some concern that convection could develop
early in the period along the nose of the LLJ. This activity is most
likely across the northern TX Panhandle into western KS atop cooler
boundary air mass that will sag south across the High Plains. This
early-day convection will likely be elevated and pose primarily a
large hail threat. However, strong surface heating near the NM/TX
border will contribute to substantial buoyancy that will become
uncapped by late afternoon. Forecast shear profiles strongly favor
supercells and a fair number of storms should ultimately evolve
across the ENH Risk. High-PW air mass should surge into this region
such that long-lived supercells are expected. Very large hail and
tornadoes can be expected with supercells south of the cold front
that will orient itself across southwest-central KS. If early-day
convection is less than currently expected, a corridor of higher
severe probs may ultimately need to be considered across the High
Plains south of the front.

...MAXIMUM RISK BY HAZARD...
Tornado: 10% - Enhanced
Wind: 30% - Enhanced
Hail: 30% SIG - Enhanced

..Darrow.. 05/22/2019

$$

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

633
ACUS03 KWNS 220742
SWODY3
SPC AC 220742

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0242 AM CDT Wed May 22 2019

Valid 241200Z - 251200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM A PORTION OF
THE CENTRAL PLAINS INTO THE UPPER MISSISSIPPI VALLEY REGION...

...SUMMARY...
A few strong to severe storms will be possible on Friday from a
portion of the upper Mississippi Valley region into a part of the
central and southern Plains.

...Synopsis...

Model consensus is that a shortwave trough initially over the
central/northern Plains early Friday will continue northeast into
the upper MS Valley region during the day. Attendant surface low
initially over SD will reach MN by mid-late afternoon with trailing
cold front extending southwest through IA and central KS. A warm
front will advance northeast through the upper MS Valley and by
early evening should extend from the surface low in MN through the
southern Great Lakes and into the Ohio Valley. Dryline will reside
across west TX during the day, but should retreat into eastern NM
during the evening.

...Eastern Kansas through the upper Mississippi Valley region...

Richer low-level moisture with mid-upper 60s F dewpoints will advect
northeast through the mid-upper MS Valley warm sector during the day
and this should contribute to a corridor of moderate instability
(1500-2000 J/kg MLCAPE) as the boundary layer warms. Some storms may
be ongoing on cool side of the warm front as well as farther west
across KS in vicinity of the cold front. Additional storms will
probably develop along the cold front or residual outflow boundaries
during the afternoon. Flow in the lowest 3 km is forecast to weaken
and the strongest mid-upper winds will likely remain north of the
warm sector which could be limiting factors for a more robust severe
threat. However, winds aloft will support 40-45 kt largely
unidirectional effective bulk shear. It appears the parameter space
will be sufficient for a threat of some strong to severe storms with
large hail and damaging wind the main threats through early evening.


...Southern High Plains area...

Storms may be ongoing from a portion of west TX into OK which
complicates the forecast to some degree. Nevertheless, initial
activity may weaken, with potential for boundary-layer recovery
during the afternoon, potentially supporting strong instability with
2000-3000 J/kg MLCAPE. A belt of 40-50 kt mid-level winds will
persist over this region, therefore the parameter space will be
conditionally supportive of severe storms. While dryline convergence
is not expected to be particularly strong and forcing aloft will be
weak, potential still exists for isolated storm development either
along the dryline or in association with residual boundaries from
early convection. Will introduce a marginal risk category this
update, but an upgrade to higher probabilities may be needed in
future outlooks once some of the mesoscale uncertainties have been
mitigated.

..Dial.. 05/22/2019

$$

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.

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.