A system of thunderstorms moved over extreme northern and northeastern Illinois late during the night of the 5th into the early morning hours of the 6th. A handful of wind damage reports were received, a large majority of which came out of McHenry County.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS LOT wrote it up.
A system of thunderstorms moved over extreme northern and northeastern Illinois late during the night of the 5th into the early morning hours of the 6th. A handful of wind damage reports were received, a large majority of which came out of McHenry County.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Chicago, IL wrote its last area forecast discussion before the first event at Aug 6, 1:15 AM CST, 1 hour earlier. Its key messages:
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
215 AM CDT Tue Aug 6 2024
.KEY MESSAGES...
- A cold front will crash through the area today leading to
cooler temperatures, low clouds, and sprinkles from time to
time.
- Dangerous swimming conditions will develop at all southern
Lake Michigan beaches this morning and last through the first
half of Wednesday.
- Dry and cooler weather is expected to continue through the
middle to the end of the week.
&&
.DISCUSSION...
Issued at 215 AM CDT Tue Aug 6 2024
Through Wednesday:
A recent hand surface analysis revealed a 1010mb surface low
pressure system centered near Cedar Rapids, Iowa, cold front
stretching southwestward through central Iowa into the central
Plains, and a warm front laid from the Wisconsin state line into
southern Lower Michigan. The surface instability axis is somewhat
displaced southwest of the synoptic warm front (thanks to
thunderstorms yesterday evening across northern Illinois), and
currently arcs from near Davenport, IA to Bloomington, IL. Showers
and thunderstorms continue along and north of the warm front in
southern Wisconsin, and have thus far had very limited penetration
into far northern Illinois.
Over the next 12 to 28 hours or so, the surface low is expected to
move east-southeastward along a path roughly from Davenport, IA to
Cincinnati, OH. As it does so, the warm front draped along the
Wisconsin state line will collapse southward through the Great
Lakes. Increasingly breezy north to northeast winds (gusting as high
as 30 mph) will usher in low-level stratus and cooler temperatures.
Meanwhile, an initially warm and sunny start to the day near US-24
will turn cooler by early afternoon as temperatures fall and low-
level stratus arrives. Stratus will linger through the afternoon
areawide, and potentially thicken near Lake Michigan leading to
areas of sprinkles. In all, today will turn decidedly "fall" like.
Low-level stratus is expected to erode from north to south this
evening and overnight as a surface high builds into the Upper Great
Lakes. Tomorrow should accordingly feature quite a bit of sunshine,
allowing highs to rebound into the upper 70s to lower 80s. Continued
breeze northeast winds will hold lakeshore locations in the lower
70s.
Finally with sustained northeasterly winds down a long fetch of Lake
Michigan today and tonight, dangerous swimming conditions will
develop and stay from this morning onward. The low-level pressure
gradient will be slow to ease, so dangerous waves will likely
continue through at least the first half of Wednesday.
Borchardt
Wednesday Night through Monday:
Dry and cooler weather is expected through the extended
forecast. A deep shortwave and surface low pressure system is
expected to advance across the northern Great Lakes on Thursday
with an associated cold front passing overhead late Thursday
night. Despite the lift provided by the cold front, no
precipitation expected due to very dry mid-level air. Highs will
be in the mid-to-upper 70s Friday and Saturday behind the cold
front with strong northerly/northwesterly flow. These strong
northerly winds could pose a threat to beachgoers this weekend,
particularly in NW IN, with large waves building.
Carothers
&&
.AVIATION /06Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 1235 AM CDT Tue Aug 6 2024
Key Aviation Messages:
- An area of convection is expected to move through the northern
portion of the area early this morning.
- MVFR to IFR CIGs will prevail through the day Tuesday.
- Strong northeasterly winds tomorrow with 25-30 kt gusts.
Discussion:
An area of ongoing convection in SW WI is expected to continue
advancing towards the area over the next couple of hours.
Uncertainty remains in the exact progression of this system
although current thinking is that it will be confined to far
northern IL. Because of this uncertainty, have not included TS
in the Chicago area TAFs. With KRFD being further north and
west, the likelihood of storms impacting the terminal are
higher, so have opted for a TEMPO with -TSRA there. KGYY looks
to be too far south for storms to impact the terminal, however,
some shower activity may come close.
The bigger impact at KGYY is the potential for reduced
visibility from fog overnight. Several areas of reduced
visibility are already present in the more rural areas of NW IN
and northern IL due to a high low-level moisture content. This
fog seems poised to spread towards, if not to, the KGYY
terminal. Have opted to cover this with a TEMPO for reduced
visibility through sunrise.
Behind the ongoing convection, MVFR to IFR CIGs are being
observed across southern MN. Expectation is that these CIGs
will move into the area tomorrow morning and persist through the
day. Currently have low-end MVFR CIGs in the TAFs, however, it
is not out of the realm of possibility that IFR CIGs prevail for
the majority of the day. CIGs should slowly start to lift and
scatter out late in the TAF period, however, MVFR CIGs will
likely hang around until early Wednesday morning.
Winds are expected to be primarily out of the SE ahead of the
convection this morning, however, they will likely swing around
to SW for an hour or two just before the convection reaches the
terminals. Behind the convection, they will turn NE and remain
there through the end of the TAF period. Tomorrow will likely
see some gusty winds (25 to 30 kt gusts), however, they will
drop off after sunset.
Carothers
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Beach Hazards Statement through Wednesday afternoon for ILZ006.
Beach Hazards Statement from 10 AM CDT this morning through
Wednesday afternoon for ILZ103-ILZ104.
IN...Beach Hazards Statement from 1 PM CDT this afternoon through
Wednesday afternoon for INZ001-INZ002.
LM...Small Craft Advisory until 3 PM CDT Wednesday for Winthrop
Harbor to Wilmette Harbor IL.
Small Craft Advisory from 10 AM this morning to 3 PM CDT
Wednesday for Wilmette Harbor to Calumet Harbor IL.
Small Craft Advisory from 1 PM this afternoon to 3 PM CDT
Wednesday for the IN nearshore waters.
&&
Visit us at weather.gov/chicagoHazardous Weather Outlook National Weather Service Chicago/Romeoville IL 300 AM CDT Tue Aug 6 2024 ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002- 010-011-019-070800- 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- 300 AM CDT Tue Aug 6 2024 /400 AM EDT Tue Aug 6 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 through mid-morning north of I-80. High Swim Risk Lake Michigan Beaches. DISCUSSION... Ongoing thunderstorms will move out of the area by mid-morning this morning. Any severe risk will be very localized. Strong and gusty northeasterly winds will generate large waves leading to dangerous swimming conditions at southern Lake Michigan beaches. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. Wednesday... High Swim Risk Lake Michigan Beaches through mid-afternoon. DISCUSSION... Strong northeasterly winds will continue into Wednesday morning generating large waves and leading to dangerous swimming conditions at all southern Lake Michigan beaches, especially in the morning and early afternoon. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be necessary through tonight. GENERAL STORM MOTION OF THE DAY: Moving toward the east-southeast at 40-45 mph. LMZ740>745-070800- 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- 300 AM CDT Tue Aug 6 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. Limited Thunderstorm Risk though mid-morning. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. Wednesday... Hazardous conditions for small craft. Carothers 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
Special Weather Statement National Weather Service Chicago/Romeoville IL 1235 AM CDT Tue Aug 6 2024 INZ001-002-010-011-061000- Lake IN-Porter-Newton-Jasper- Including the cities of Gary, Hammond, Merrillville, Portage, Valparaiso, Chesterton, Roselawn, Kentland, Morocco, Rensselaer, and DeMotte 1235 AM CDT Tue Aug 6 2024 ...Patchy dense fog through the overnight hours... Patchy dense fog with visibility locally at or below one quarter of a mile will continue through the overnight hours. Fog should gradually improve before sunrise. If planning to drive overnight, travel at slower speeds, increase following distance, use low beam lights. Borchardt
Preliminary Local Storm Report
National Weather Service Chicago IL
112 AM CDT Tue Aug 6 2024
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0748 AM Tstm Wnd Gst 4 NE Beverly Shores 41.73N 86.93W
08/05/2024 M52 MPH LMZ745 IN C-Man Station
Corrects time of previous tstm wnd gst
report from 4 NE Beverly Shores.
&&
ROSpecial Weather Statement
National Weather Service Chicago/Romeoville
253 AM CDT Tue Aug 6 2024
ILZ004-005-060845-
Boone IL-McHenry IL-
253 AM CDT Tue Aug 6 2024
...A STRONG THUNDERSTORM WILL IMPACT MCHENRY AND BOONE COUNTIES
THROUGH 345 AM CDT...
At 252 AM CDT, Doppler radar was tracking a line of strong
thunderstorms from near Poplar Grove to near Harvard, moving east at
45 mph.
HAZARD...Wind gusts of 50 to 55 mph and half inch hail.
SOURCE...Personal weather stations.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation is
possible.
Locations impacted include...
Crystal Lake, Lake in the Hills, McHenry, Woodstock, Loves Park, Fox
Lake, Harvard, Island Lake, Marengo, Poplar Grove, Cary, Johnsburg,
Lakemoor, Twin Lakes, Spring Grove, Candlewick Lake, Fox River Grove,
Wonder Lake, Lakewood, Pistakee Highlands, Genoa City, Oakwood Hills,
Prairie Grove, Richmond, and Sharon.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
&&
LAT...LON 4250 8820 4219 8820 4230 8894 4250 8894
TIME...MOT...LOC 0752Z 277DEG 37KT 4242 8885
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...55 MPH
OgorekThe Milwaukee radar (KMKX), 62 km away, was scanning. The volume nearest the first event began at 08:17 UTC.
7 thunderstorm wind. Local standard time, as filed.
Power poles were downed along Thayer Road between Alden and Johnson Roads east of Harvard.
Eight large hardwood trees were downed along Keystone Rd south of Tryon Grove Rd near Richmond.
Several trees were reported down in and around Woodstock.
Photos shared via social media showed large tree limbs down around Crystal Lake.
Photos shared via social media showed several trees and a light pole down around the Algonquin and Lake of the Hills area including one large tree that fell onto a shed. Minor roofing and siding damage to one building was also noted.
A photo shared via social media showed a large tree limb and several smaller branches down in Lakewood.
A large willow tree snapped at its trunk and crushed a fence along County Line Rd in Barrington Hills.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2024Every state in 2024This day in weather historyWarnings in Illinois, August 2024
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1202949, 1202954, 1202956, 1202965, 1202967, 1202961, 1202970.