Scattered strong to severe thunderstorms developed during the afternoon of June 17th and continued into the evening producing wind damage and heavy rain.
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.
Scattered strong to severe thunderstorms developed during the afternoon of June 17th and continued into the evening producing wind damage and heavy rain.
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 Jun 17, 1:24 PM CST, 2 hours 9 minutes earlier.
Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 224 PM CDT Sat Jun 17 2017 .UPDATE... 208 PM CDT Update to indicate the 18z DVN and ILX radiosonde launches are in. Instability on these balloon soundings is lower than the RAP analyzed mixed layer cape and do depict some inhibition. We are still awaiting the approach of better forcing aloft to arrive, so we do expect forcing and steeper lapse rates to eventually advect eastward, thunder coverage may just take a little longer to fill in. Evidence of increased forcing is showing up with some shower activity already beginning this afternoon on KLOT Radar, and generally along a series of convergence boundaries laid out across our area, and expect this to continue for the remainder of the afternoon. Thunder threat initially is low, and cores are not growing super high yet, but 30 dbz echoes are briefly getting above the -20C level such that the thunder threat is not zero. The initial hail threat later today still appears to be focused along these convergence boundaries, which is slightly farther north than the current enhanced risk area. KMD && .SHORT TERM... 105 PM CDT Through tonight... MCV left over from earlier shower and storm activity has shifted offshore this afternoon. Focus turns west to a sharp upper level trough axis across the northern plains. While the clouds and showers have limited instability here initially, there is some pooled moisture along and ahead of the surface trough/cold front, which is maintaining moisture advection into northeast IL and northwest IN. MLCAPE values of 1000-1500 J/KG remain in place area-wide and are forecasted to increase some. While upstream things do not look great on satellite, there is an area of decent clearing across southern IA into the Mississippi. Mid level vort/speed maximum across IA and NE will spread east late this afternoon and early evening interacting with with the east/southeastward shifting trough axis providing additional lower level lift. With the forecasted 1000-1500 J/KG of MLCape, expect at least isolated convection to initiate later this afternoon. As theta-e advection ramps up more so this evening with the lead speed max, expect coverage to significantly expand. Effective shear profiles quickly ramp up to support storm organization. The area most favored appears to be along and ahead of the surface trough axis, with its position crucial in coverage of storms. While some guidance suggests the I-80 corridor southward may be favored for better coverage, as this lead wave comes in the trough will likely bisect the CWA from LaSalle county northeastward to northern Cook County IL, and this really the most favored axis for severe storms. There is still some uncertainty on coverage at this point. The overall risk area is still well outlined in the entire Slight/Enhanced Risk keeping a threat for severe storms really along and ahead of this axis. If the trough axis is farther south areas northwest will have a much lower threat. Mid level lapse rates do increase and the shear in the layer support a hail threat initially for our area with these initial storms. Eventual storm organization will lead to a damaging wind concern. While the tornado threat is not zero, it is appears on the low side given the weak lower level wind field being in the trough axis and veered wind profile. Regarding the wind concern, With time expect a line of storms to form, but it is possible that worst of this developing line may shift south with the surface boundary ahead of the main upper trough. We still await the main upper trough which will come through overnight, there is still convective potential during the post midnight hours, with a cold front eventually helping to scour things out by daybreak. The more organized activity is still favored in the evening for our area. More to come on this convective evolution situation, with mesocale discussions likely to be issued throughout the afternoon/evening as convective trends emerge. KMD && .LONG TERM... 223 PM CDT Sunday through Saturday... A cooler and drier air mass expected to be in place early in the period with Sunday expected to be generally dry, as any lingering precip departs to the east in the morning. However, with the upper level trough still situated just to the northwest, area will remain in cyclonic flow. This could allow isolated showery development Sunday afternoon across the area, which some guidance is hinting at this possibility. Some weak instability not out of the question by the afternoon, with an isolated storm or two also possible. With his cooler air mass, cooler and near normal temps expected. With no real big changes in the overall pattern, Monday and Tuesday are looking to be fairly similar days with continued chances for afternoon showers/thunderstorms and with cooler temps. However, guidance is showing the possibility for slightly stronger wave to move through the region Tuesday afternoon. So, could see slightly more coverage of precip during that time. Upper level trough begins to shift to the east by mid week with more zonal flow returning to the region. In this setup, region would be favored for mid level energy to stream overhead, which guidance is indicating through the end of the work week. Periods of showers and thunderstorms will be once again possible, with some warmth also returning during this time. Rodriguez && .AVIATION... For the 18Z TAFs... Concerns center on thunderstorm coverage and timing, especially this evening. MCV from morning activity has left some MVFR clouds in its wake. Forecast soundings and MOS guidance do depict this lifting in the afternoon. There is a surface trough just to our west, and gusty sw winds continue ahead of it. But as the MCV shifts east, the surface trough is expected to do so also, which should allow winds to become more westerly with time while weakening. There is a leading shortwave ahead of the main upper level trough across the northern plains. This first wave will interact with the surface trough axis aiding in lift and expect that isolated scattered convection is expected as early as late afternoon. Forecast soundings suggest by this time enough recoveries have occurred to support an initial window of thunderstorms, with the 1z-5z time frame appearing to be the most likely period. While the focus of the stronger storms appears to be south of the terminals, the wave is strong enough so support carrying the TS mention in the Chicago TAFs at this time. Note for the Tracon that while the southern gates have a good chance of being impacted, isolated to scattered activity remains possible in most areas. Coverage will likely be lowest near RFD. Southwest winds trend back to south and even southeast or east for both ORD and MDW for a time as the surface trough moves east and even overhead, and this includes during the prime T-storm window. Confidence on winds during this time is not very high and likely to be somewhat chaotic. Behind this after 6z, generally winds shift a west component The upper trough will still shift through overnight which does suggest even some continued showers, or an isolated storm. KMD && .MARINE... 223 PM CDT Surface pattern somewhat organized across the region, however, still supportive of southerly winds across the lake with speeds staying confined to 10 to 20 KT. Expect winds to generally stay southerly for most of tonight, but am monitoring for thunderstorms to impact mainly the southern half of the lake. This could allow for winds to be highly variable this evening, including speeds. Deepening surface low will move across the lake later tonight into early Saturday morning with winds expected to turn more westerly. Some slight increase in speeds on Monday, possibly in the 15 to 25 kt range. At this time, these speeds should be just below hazardous conditions for small craft. Rodriguez && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...None. && VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
420 PM CDT Sat Jun 17 2017
ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
182130-
Winnebago-Boone-McHenry-Lake Illinois-Ogle-Lee-De Kalb-Kane-
DuPage-Cook-La Salle-Kendall-Grundy-Will-Kankakee-Livingston-
Iroquois-Ford-Lake Indiana-Porter-Newton-Jasper-Benton-
420 PM CDT Sat Jun 17 2017 /520 PM EDT Sat Jun 17 2017/
THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL ILLINOIS...
NORTHEAST ILLINOIS AND NORTHWEST INDIANA.
.DAY ONE...Tonight.
WEATHER HAZARDS EXPECTED:
Significant Thunderstorm Risk...with an associated:
Limited Tornado Risk.
Significant Hail Risk...up to half dollar size.
Significant Thunderstorm Wind Damage Risk...up to 70 MPH.
Elevated Flooding Risk.
DISCUSSION:
Scattered thunderstorms are likely late this afternoon into the
early evening across the entire outlook area. Severe threats of
hail, damaging winds, and heavy rainfall will be possible with any
storm. More widespread thunderstorms are expected later this
evening into the overnight hours, once again, across all of
northern Illinois and northwest Indiana. Damaging winds and heavy
rainfall will be the main threats, along with possible flash
flooding.
.DAYS TWO THROUGH SEVEN...Sunday through Friday.
Sunday through Tuesday...
Limited Thunderstorm Risk.
Wednesday through Friday...
Elevated Thunderstorm Risk.
.SPOTTER INFORMATION STATEMENT...
Spotters will likely be needed late this afternoon into this
evening across the entire outlook area.
GENERAL STORM MOTION OF THE DAY:
East northeast at around 30 MPH.
&&
LMZ740>745-182130-
Winthrop Harbor to Wilmette Harbor-
Wilmette Harbor to Northerly Island-
Northerly Island to Calumet Harbor-Calumet Harbor to Gary-
Gary to Burns Harbor-Burns Harbor to Michigan City-
420 PM CDT Sat Jun 17 2017
THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE ILLINOIS NEARSHORE
WATERS OF LAKE MICHIGAN AND THE INDIANA NEARSHORE WATERS OF LAKE
MICHIGAN.
.DAY ONE...Tonight.
Significant Thunderstorm Risk...which includes possible wind
gusts in excess of 33 knots and hail.
.DAYS TWO THROUGH SEVEN...Sunday through Friday.
Monday and Tuesday...
Limited Thunderstorm Risk.
Wednesday...
Elevated Thunderstorm Risk.
Thursday and Friday...
Limited Thunderstorm Risk.
&&
LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-868-
870-872-874-876-878-182130-
Lake Michigan from Michigan City IN to St. Joseph MI 5 NM
offshore to Mid Lake-
Lake Michigan from Seul Choix Point to Rock Island Passage 5 NM
offshore to Mid Lake-
Lake Michigan South of a line from Seul Choix Point to the
Mackinac Bridge and north of a line from Charlevoix MI to South
Fox Island 5 NM offshore-
Lake Michigan from Charlevoix to Point Betsie MI 5 NM offshore to
Mid Lake-
Lake Michigan from Point Betsie to Manistee MI 5 NM offshore to
Mid Lake-
Lake Michigan from Rock Island Passage to Sturgeon Bay WI-
Lake Michigan from Sturgeon Bay to Two Rivers WI 5 NM offshore to
Mid Lake-
Lake Michigan from Two Rivers to Sheboygan WI 5 NM offshore to
Mid Lake-
Lake Michigan from Sheboygan to Port Washington WI 5 NM offshore
to Mid Lake-
Lake Michigan from Port Washington to North Point Light WI 5 NM
offshore to Mid Lake-
Lake Michigan from North Point Light to Wind Point WI 5 NM
offshore to Mid Lake-
Lake Michigan from Wind Point WI to Winthrop Harbor IL 5 NM
offshore to Mid Lake-
Lake Michigan from Winthrop Harbor to Wilmette Harbor IL 5 NM
offshore to Mid Lake-
Lake Michigan from Wilmette Harbor IL to Michigan City IN 5 NM
offshore to Mid Lake-
Lake Michigan from Pentwater to Manistee MI 5 NM offshore to Mid
Lake-
Lake Michigan from Whitehall to Pentwater MI 5 NM offshore to Mid
Lake-
Lake Michigan from Grand Haven to Whitehall MI 5 NM offshore to
Mid Lake-
Lake Michigan from Holland to Grand Haven MI 5 NM offshore to Mid
Lake-
Lake Michigan from South Haven to Holland MI 5 NM offshore to Mid
Lake-
Lake Michigan from St. Joseph to South Haven MI 5 NM offshore to
Mid Lake-
420 PM CDT Sat Jun 17 2017
THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE OPEN WATERS OF LAKE
MICHIGAN.
.DAY ONE...Tonight.
Thunderstorms are likely through this evening. Wind gusts in
excess of 33 knots are possible mainly across the south half.
.DAYS TWO THROUGH SEVEN...Sunday through Friday.
There are chances for thunderstorms through the period.
&&
Rodriguez
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www.youtube.com/nwschicagoSpecial Weather Statement National Weather Service Chicago/Romeoville Il 417 PM CDT SAT JUN 17 2017 ILZ012>014-172145- Kane IL-Cook IL-DuPage IL- 417 PM CDT SAT JUN 17 2017 ...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL KANE...NORTHWESTERN DUPAGE AND NORTHWESTERN COOK COUNTIES UNTIL 445 PM CDT... At 416 PM CDT, Doppler radar was tracking a strong thunderstorm over Wayne, or near Elgin, moving east at 25 mph. Dime size hail and winds in excess of 40 mph will be possible with this storm. Locations impacted include... Elgin, Schaumburg, Palatine, Wheaton, Hoffman Estates, Carol Stream, Addison, St. Charles, Glen Ellyn, West Chicago, Rolling Meadows, Roselle, Dupage Airport, Bartlett, Streamwood, Hanover Park, Elk Grove Village, Winfield, Itasca and Inverness. LAT...LON 4194 8837 4205 8836 4210 8802 4186 8806 TIME...MOT...LOC 2116Z 269DEG 23KT 4199 8827 RATZER
Special Weather Statement National Weather Service Chicago/Romeoville Il 426 PM CDT SAT JUN 17 2017 ILZ003-008-172200- Winnebago IL-Ogle IL- 426 PM CDT SAT JUN 17 2017 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN OGLE AND SOUTHEASTERN WINNEBAGO COUNTIES UNTIL 500 PM CDT... At 426 PM CDT, Doppler radar was tracking a strong thunderstorm near Stillman Valley, or near Oregon, moving northeast at 30 mph. Nickel size hail and winds in excess of 40 mph will be possible with this storm. Locations impacted include... Rockford, Byron, Cherry Valley, Stillman Valley, Davis Junction and New Millford. Including the following interstate... I-39 between mile markers 103 and 121. LAT...LON 4198 8928 4210 8933 4225 8898 4197 8898 TIME...MOT...LOC 2126Z 246DEG 26KT 4206 8923 RATZER
The Chicago radar (KLOT), 107 km away, was scanning. The volume nearest the first event began at 21:32 UTC.
6 thunderstorm wind, 2 heavy rain. Local standard time, as filed.
Tree damage was reported with power lines blown down in two mobile home parks near Stillman Road. A commercial seed building was damaged and a propane tank was moved.
Heavy rainfall of 1.25 inches was measured in 30 minutes near Walkup and Crystal Springs Road.
Trees and power lines were blown down.
Trees and power lines were blown down.
Heavy rainfall of 1.25 inches was measured in 30 minutes.
Trees and power lines were blown down.
Wind gusts were estimated to 60 mph.
Numerous trees and tree limbs were blown down along with some power lines. One tree was blocking the road near Church and 8th Streets. Most of the damage was concentrated between 8th and 14th streets, east of Sangamon Street.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2017Every state in 2017This day in weather historyWarnings in Illinois, June 2017
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: 717069, 717075, 717070, 717072, 717077, 717073, 717074, 717078.