Special Weather Statement
National Weather Service Chicago/Romeoville Il
1249 PM CDT TUE JUN 26 2018
Winnebago IL-Ogle IL-La Salle IL-Lee IL-
1249 PM CDT TUE JUN 26 2018
…SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN LA SALLE…OGLE…
LEE AND WINNEBAGO COUNTIES UNTIL 145 PM CDT…
At 1246 PM CDT, Doppler radar was tracking thunderstorms along a
line extending from near Freeport to near Sterling. Movement was
northeast at 35 mph. Another area of thunderstorms was near Sublette
to Princeton, also moving northeast at 35 mph.
Funnel clouds and winds in excess of 40 mph will be possible with
these storms. If rotation strengthens in these storms, a tornado
warning may be needed.
In addition, brief but very heavy rainfall is occurring with these
storms. This could result in localized flooding, especially given
the recent wet conditions.
Locations impacted include…
Rockford, Loves Park, Machesney Park, Dixon, Rochelle, South Beloit,
Rockton, Mendota, Oregon, Mount Morris, Rockford Airport, Walton,
Roscoe, Byron, Cherry Valley, Winnebago, Amboy, Polo, Pecatonica and
Torrential rainfall is also occurring with these storms, and may lead
to localized flooding. Do not drive your vehicle through flooded
1207 PM CDT Tue Jun 26 2018 /107 PM EDT Tue Jun 26 2018/
This Hazardous Weather Outlook is for portions of North Central
Illinois…Northeast Illinois and Northwest Indiana.
.DAY ONE…This Afternoon and Tonight.
Weather hazards expected…
Significant Thunderstorm Risk…with an associated:
Elevated Tornado risk.
Elevated Damaging Wind Risk…up to 60 mph.
Limited Hail Risk…up to quarter size.
Elevated Flooding Risk.
Scattered thunderstorms are expected across north central Illinois
early this afternoon that may pose a brief tornado threat. More
thunderstorms are expected later this afternoon into the evening
across the area. These will have severe weather potential, mainly
across north central Illinois. These will be capable of at least
brief tornadoes and severe winds. The storms will shift eastward
into northeast Illinois late this afternoon into evening, with still
a limited severe weather threat, though it should gradually ease
through the evening.
Brief very heavy rain will also accompany these storms, and this
may result in areas of flash flooding across northern Illinois into
Hazardous swim conditions are expected at the Lake County Illinois
beaches through this afternoon.
Some area rivers will remain in flood.
In the brief torrential downpour that moved through #Rockford around the top of the hour, 0.56″ fell between 5:54-55 am and 6:05 am, which brings June rainfall total to 12.59″. 1.39″ from tying August 2007 for wettest overall month on record. #ilwx -NWS Chicago
Scattered thunderstorms this morning, then mainly cloudy during the afternoon with thunderstorms likely.
A few storms may be severe. High 78F. Winds SE at 10 to 15 mph. Chance of rain 100%.
Thunderstorms this evening, then skies turning partly cloudy after midnight.
Low around 65F. Winds SW at 5 to 10 mph. Chance of rain 80%
…Iowa through northern Illinois and southern Wisconsin…
Modest instability is expected in warm sector. Storms will continue
developing in association with vorticity maxima rotating through
upper low circulation, and 35-40 kt effective bulk shear will
support some supercell structures. If sufficient boundary layer
destabilization occurs, threat will exist for a few tornadoes as
storms move northeast and interact with warm front across eastern IA
into northern IL and southern WI this afternoon into early evening.
Isolated to scattered non-severe storms are expected this morning. More storms are expected this afternoon and evening, and severe storms are possible across all of Northern Illinois.
The main threats will be damaging winds and flash flooding, and tornadoes are possible across North-Central Illinois.
Large hail is possible with supercells. Flash flooding is more likely north of I-80, and a Flash Flood Watch is in effect from 1PM to 1AM CDT.
FLASH FLOOD WATCH IN EFFECT FROM 1 PM CDT THIS AFTERNOON
THROUGH LATE TONIGHT…
The National Weather Service in Chicago has issued a
* Flash Flood Watch for portions of north central Illinois and
northeast Illinois, including the following areas, in north
central Illinois, Boone, DeKalb, La Salle, Lee, Ogle, and
Winnebago. In northeast Illinois, Cook, DuPage, Kane, Kendall,
Lake IL, and McHenry.
* From 1 PM CDT this afternoon through late tonight
* Periods of heavy rain are expected this afternoon through the
evening.Given recent heavy rainfall, any additional heavy rain
may produce localized flash flooding.
* Area rivers and streams are running high and the ground remains
moist, which will cause rainfall to more quickly go into
A Flash Flood Watch means that conditions may develop that lead
to flash flooding. Flash flooding is a very dangerous situation.
You should monitor later forecasts and be prepared to take action
should Flash Flood Warnings be issued.