2 products issued by NWS for: Ottawa IL
Hazardous Weather Outlook
Hazardous Weather Outlook...UPDATED
National Weather Service Chicago/Romeoville IL
650 AM CDT Sun Aug 16 2026
ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-171200-
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-
650 AM CDT Sun Aug 16 2026 /750 AM EDT Sun Aug 16 2026/
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 Fog Risk early this morning.
Limited Flooding Risk early this morning.
Limited Thunderstorm Risk.
DISCUSSION...
Areas of fog, some locally dense, is expected through mid morning
mainly west and northwest of Chicago.
Localized heavy rainfall may lead to ponding on roadways, mainly
south of a Pontiac to Rensselaer line through mid morning.
Isolated to widely scattered thunderstorms may develop along a
cold front this afternoon and evening. A few storms may be
capable of gusty winds, mainly south of a Pontiac to Valparaiso
line.
.DAYS TWO THROUGH SEVEN...Monday through Saturday.
Tuesday...
Elevated Flooding Risk.
Limited Thunderstorm Risk...with an associated:
Level 1 of 5 Severe Thunderstorm Risk.
Wednesday...
Limited Thunderstorm Risk.
DISCUSSION...
Thunderstorm chances return late Tuesday into Wednesday, some
could be strong to severe and produce torrential rainfall which
may lead to flooding.
.SPOTTER INFORMATION STATEMENT...
Spotter activation will not be necessary through tonight.
GENERAL STORM MOTION OF THE DAY:
Moving toward the southeast around 30 mph.
$$
Flood Warning
Flood Statement
National Weather Service Chicago IL
1002 PM CDT Sat Aug 15 2026
...The Flood Warning continues for the following rivers in
Illinois...
Illinois River at La Salle affecting Bureau, La Salle and Putnam
Counties.
For the Illinois River (Upper)...including Morris, Ottawa, La
Salle...Minor flooding is forecast.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A Flood Warning means water levels above flood stage are imminent or
may already be occurring. Persons along rivers and streams in the
warned area should take immediate precautions to protect life and
property.
These forecasts are based on observed precipitation as well as
forecast precipitation 24 hours into the future. Changes to the
rainfall forecast, or any additional rainfall after 24 hours, may
cause changes to these river forecasts.
Additional information is available at www.weather.gov.
The next statement will be issued by Sunday afternoon.
&&
ILC011-099-155-162115-
/O.EXT.KLOT.FL.W.0071.000000T0000Z-260820T0000Z/
/LSLI2.1.ER.260816T1424Z.260818T0000Z.260819T1800Z.NO/
1002 PM CDT Sat Aug 15 2026
...FLOOD WARNING NOW IN EFFECT UNTIL WEDNESDAY EVENING...
* WHAT...Minor flooding is forecast.
* WHERE...Illinois River from Starved Rock Lock and Dam downstream to
confluence with Big Bureau Creek, including the La Salle gauge.
* WHEN...Until Wednesday evening.
* IMPACTS...At 22.0 feet, Lower parking lot at Starved Rock State
Park is inundated east of La Salle. High water levels begin to
impact shipping interests along the river.
* ADDITIONAL DETAILS...
- At 9:45 PM CDT Saturday the stage was 19.5 feet.
- Forecast...The river is expected to rise above flood stage late
tomorrow morning to a crest of 22.4 feet Monday evening. It will
then fall below flood stage early Wednesday afternoon.
- Flood stage is 20.0 feet.
- http://www.weather.gov/safety/flood
&&
LAT...LON 4131 8940 4135 8933 4137 8898 4128 8899
4128 8929
$$
Yack